Abstracts


High-temperature ceramic composites directionally reinforced with high-entropy borides


Iurii Bogomol, Elmira Ferkhatly, Mantang Duan, Dmytro Rieznik, Serhii Ponomarchuk, Yaroslav Zaulychnyi, Oleh Stepanov, Vasyl Mosiak, Kira Kryvenko, Dmytro Palagecha

ubohomol@iff.kpi.ua


National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


Materials based on boron and silicon carbides are increasingly used in industry due to its unique complex of physical and mechanical properties mostly at high temperatures up to 2000 o C [1]. One of the most effective ways to improve the strength of the ceramics is a fiber reinforcement, which is realized in the directional solidification of eutectic alloys. In recent years, high-entropy borides (HEB) have attracted considerable interest due to their potential applications as high-temperature structural materials [2]. I this work au- thors used high-entropy borides as the reinforced phase during directional solidification of eutectic alloys based on boron and silicon carbides [3]. The directionally solidified com- posites (В 4 С-HEB, SiC-HEB) were prepared by the floating zone method based on the crucible-free zone melting of compacted powders and Spark Plasma Sintering. B 4 C, SiC and powders of transitional metals diborides (TiB 2 , ZrB 2 , HfB 2 , TaB 2 and NbB 2 ) with technical purity were used as the initial materials. The microstructure of all as pre- pared alloys consists of B 4 C or SiC matrix uniformly reinforced by single phase diboride fibers and lamellas. The formation of eutectic structure, phase compositions and some mechanical properties of the directionally reinforced composites were discussed.

References


1. A.K. Suri, C. Subramanian, J.K. Sonber, T.S.R.C. Murthy, Synthesis and consolidation of boron carbide: a review, Int. Mater. Rev., 2010, Volume 55, P. 4-38.
2. Mantang Duan, I. V. Solodkyi, and Y. I. Bogomol Recent Advancements in the Synthesis of High-Entropy Boride Ceramics: A Review, Journal of Superhard Materials, 2023, Vol. 45, No. 6, pp. 434–443. 3. Iurii Bogomol, Elmira Ferkhatly, Serhii Ponomarchuk, Yaroslav Zaulychnyi, Myroslav Karpets, Ievgen Solodkyi Ceramic Eutectic Composites Based on B 4 C Directionally Reinforced by High-entropy (TiZrHfNbTa)B 2 boride, Journal of the European Ceramic Society. 2024, Volume 44, Issue 1, P. 51-57.

IXth International Samsonov Conference “MATERIALS SCIENCE OF REFRACTORY COMPOUNDS”


CERAMICS AND COMPOSITES



High-temperature ceramic composites directionally reinforced with high-entropy borides


Iurii Bogomol, Elmira Ferkhatly, Mantang Duan, Dmytro Rieznik, Serhii Ponomarchuk, Yaroslav Zaulychnyi, Oleh Stepanov, Vasyl Mosiak, Kira Kryvenko, Dmytro Palagecha

ubohomol@iff.kpi.ua


National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


Materials based on boron and silicon carbides are increasingly used in industry due to its unique complex of physical and mechanical properties mostly at high temperatures up to 2000 o C [1]. One of the most effective ways to improve the strength of the ceramics is a fiber reinforcement, which is realized in the directional solidification of eutectic alloys. In recent years, high-entropy borides (HEB) have attracted considerable interest due to their potential applications as high-temperature structural materials [2]. I this work au- thors used high-entropy borides as the reinforced phase during directional solidification of eutectic alloys based on boron and silicon carbides [3]. The directionally solidified com- posites (В 4 С-HEB, SiC-HEB) were prepared by the floating zone method based on the crucible-free zone melting of compacted powders and Spark Plasma Sintering. B 4 C, SiC and powders of transitional metals diborides (TiB 2 , ZrB 2 , HfB 2 , TaB 2 and NbB 2 ) with technical purity were used as the initial materials. The microstructure of all as pre- pared alloys consists of B 4 C or SiC matrix uniformly reinforced by single phase diboride fibers and lamellas. The formation of eutectic structure, phase compositions and some mechanical properties of the directionally reinforced composites were discussed.

References


1. A.K. Suri, C. Subramanian, J.K. Sonber, T.S.R.C. Murthy, Synthesis and consolidation of boron carbide: a review, Int. Mater. Rev., 2010, Volume 55, P. 4-38. 2. Mantang Duan, I. V. Solodkyi, and Y. I. Bogomol Recent Advancements in the Synthesis of High-Entropy Boride Ceramics: A Review, Journal of Superhard Materials, 2023, Vol. 45, No. 6, pp. 434–443. 3. Iurii Bogomol, Elmira Ferkhatly, Serhii Ponomarchuk, Yaroslav Zaulychnyi, Myroslav Karpets, Ievgen Solodkyi Ceramic Eutectic Composites Based on B 4 C Directionally Reinforced by High-entropy (TiZrHfNbTa)B 2 boride, Journal of the European Ceramic Society. 2024, Volume 44, Issue 1, P. 51-57.



Modern technologies of synthesis, 3D printing and consolidation for the manufacture of products from composite materials based on refractory compounds.


Ostap Zgalat-Lozynskyy

zgalatlozynskyy@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The results of the conducted research became the basis for the development of technology for the synthesis and consolidation of composite materials based on refractory compounds for the manufacture of products that are operated in conditions of extreme temperatures, loads and aggressive environments, as well as the latest materials for 3D printing using Robocasting and FDM technologies. Scientific and practical approaches to obtaining wear- resistant composite materials based on refractory compounds are proposed. The novel approaches of consolidation consist in the use of non-linear modes of materials densifica- tion under electrosintering conditions, which made it possible to obtain a number of new composite nanomaterials (grain size ~ 50 nm). The composites based on silicon, titanium, zirconium and niobium nitrides demonstrate a level of wear resistance 2-3 times higher than existing industrial analogues [1] . The technology for the synthesis of composite nan- odisperse powders based on silicon nitride in a single technological cycle and nonlinear modes of their consolidation by the methods of spark-plasma sintering and sintering with controlled compaction speed to obtain wear-resistant ceramic products with the effect of self-healing of defects has been developed. A batch of ceramic balls with a diameter of 12 mm and 14 mm was produced for a hybrid rolling bearing with an extended service life, which is promising for use in aviation technology. For the first time in Ukraine, the tech- nology of 3D printing by the Robocasting method was introduced for the manufacture of products of complex shape from composite materials based on refractory compounds and biocomposites [2,3] . IIt has been proven that the use of spark-plasma and microwave sin- tering is promising for obtaining products of complex shape from polymer-ceramic blanks made by 3D printing by the layer deposition method [4].

References


[1] O. Zgalat-Lozynskyy, I. Kud, L. Ieremenko, L. Krushynska, D. Zyatkevych, K. Grinkevych, O. Mys- lyvchenko, V. Danylenko, S. Sokhan, A. Ragulya, Synthesis and spark plasma sintering of Si3N4–ZrN self-healing composites, Journal of the European Ceramic Society, Volume 42, Issue 7, 2022, Pages 3192-3203, https://doi.org/10.1016/j.jeurceramsoc.2022.02.033. [2] Zgalat-Lozynskyy, O.B. Materials and Techniques for 3D Printing in Ukraine (Overview). Powder Metall Met Ceram 61, 398–413 (2022). https://doi.org/10.1007/s11106- 023-00327-y [3] V. Naumenko, O. Zgalat-Lozynskyy, D. Zyatkevych, 3D printing of the ceramic materials based on Mo₀.₉Cr₀.₁Si₂ by Robocasting technique. Book of Abstracts, 8th International Materials Science Conference HighMatTech-2023, p. 17. October 2-6, 2023 Kyiv, Ukraine [4] Zgalat-Lozynskyy, O.B., Matviichuk, O.O., Litvyn,

R.V. et al. Microwave Sintering of 3D Printed Composites from Polymers Reinforced with Titanium Nitride Particles. Powder Metall Met Ceram 62, 164–173 (2023). https://doi.org/10.1007/s11106-023-00380-7



Superhard Boride Ceramics Produced by Boro-Carbothermal Reduction


William G. Fahrenholtz

-


Missouri University of Science and Technology, United States


Boride ceramics have been proposed for use in extreme environments based on melting temperatures above 3000°C and other attractive properties such as high hardness. In- spired by the research of Professor Samsonov and others, our laboratory has investigated compositionally complex borides containing five different transition metals in an effort to identify new superhard ceramics. The most commonly studied compositionally com- plex boride has been (Hf,Nb,Ta,Ti,Zr)B2 with the metals present in nominally equimo- lar amounts. The initial search for harder materials involved substituting metals such as Cr, Mo, or W in place of Nb, which increased the hardness. Among the materials produced, (Cr,Hf,Ta,Ti,Zr)B2 had the highest hardness, which was about 48 GPa at a load of 0.49 N. Subsequently, new boride compositions were identified using a computa- tional approach called the Disordered Enthalpy-Entropy Descriptor (DEED). Using DEED, (Cr,Mo,Ti,V,W)B2 was identified as a thermodynamically stable compound. The dense ceramic had a hardness of 48 GPa at a load of 0.49 N. Recently, machine learning pre- dicted that (Hf,Mo,Ti,V,W)B2 should be superhard. This composition was synthesized by our group and found to have a hardness of 66 GPa at a load of 0.49 N. This presentation will provide a broad perspective on promising approaches for synthesis and densification of new borides that are identified through computational studies and produced by boro- carbothermal reduction.

References



New composites based on aluminium alloy grinding waste for post-printing machines


Tetiana Roik, Oleg Gavrysh, Iuliia Maistrenko

roik2011@gmail.com


National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


Post-printing equipment contains many antifriction parts made of cast aluminum alloys that work at sliding speeds up to 2.0 m/s and loads up to 3.0 MPa with liquid lubrication. Such parts often have unsatisfactory functional properties due to unstable lubricant supply to the contact area or other emergencies [1]. This leads to damage to the part, the unit, and the post- printing equipment as a whole. The use of grinding waste has become an alternative for creating new effective aluminium antifriction composites. The objective of the study is to determine the structure and properties of new antifriction composites based on grinding waste of aluminium alloy D16+(6.0‒8.0) wt.% MoS2. The initial D16 alloy grinding waste was subjected to regeneration: cleaning from abrasives and drying. D16 alloy powders were mixed with (6.0-8.0)wt.%MoS2, cold-pressed at 550 MPa, and followed by hot pressing at 300 MPa and 400°C to minimise porosity. The structure was studied using metallographic, scanning electron microscopes and X-ray spectroscopy [1]. The tribological tests were carried out on the VMT-1 friction machine at a speed of 1.0-2.0 m/s and friction pair loads of 2.0-3.0 MPa in pair with a 40Kh steel counterface (HRC 47-49). The microstructure is a metal matrix (Al α-solid solution) based on the D16 aluminium alloy regenerated grinding waste and uniformly distributed MoS2 solid lubricant. Antifriction tests showed the advantages of the new composite made from the D16 alloy waste over cast aluminium alloy D16. The friction coefficient of the new composite was 0.16-0.18, and wear intensity was 32-37 µm/km in tribological tests at 3.0 MPa and sliding speed of 2.0 m/s. While the cast alloy D16 at operation without lubrication had a friction coefficient of 0.38-0.39 and wear intensity of 75-80 µm/km. The developed technology provided a high level of functional properties and stable operation of the composite in self-lubrication mode.

References


[1] Roik, T. A., Gavrysh, O. A. Vitsiuk, I .I. Composite Antifriction Material Based on Wastes of Aluminum Alloy for Items of Post-Printing Equipment . Powder Metall. Met. Ceram. 2020. V.59. №5-6. P. 282-289.



The correlation between electric and thermoelectric properties in percolative Co/Al₂O₃, Co/SiO₂ and Co/TiO₂ ferromagnetic nanocomposites


Oleksii Baibara1, Marina Bugaiova1, Yaroslav Stelmakh2, Larisa Krushinskaya2, Arsenii Ievtushenko1

o.baibara@ipms.kyiv.ua

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2E.O. Paton Electric Welding Institute, Ukraine

Ferromagnetic nanocomposites (FMNC), consisting of ferromagnetic nanoparticles dis- tributed in a dielectric matrix, behaves as a disordered system in the strongly localized regime [1,2]. Granular structure determines the specific properties of FMNCs, in partic- ular, the metal–insulator transition induced by a change in metal content x, so below per- colation threshold, the metallic granules in ferromagnetic nanocomposites are separated by dielectric layers, and hopping transport (HT) to be predominant. From a structural point of view, FMNCs are different from doped materials, therefore, debate arises in how to extend the HT model of doped materials to granular composites. One of the primary concerns focuses on the value of characteristic temperature T₀. Ferromagnetic nanocom- posites with Co nanoparticles distributed in various dielectric amorphous matrixes Al₂O₃, SiO₂ and TiO₂ were grown by the EB-PVD method in the form of film with thickness from

0.8 to 10 μm on Al₂O₃ substrates (polycor). The Cо concentration x varied in wide region from 10 to 70 at.% for all matrixes. The temperature dependences of the resistance and thermoelectric properties for FMNCs Co/Al₂O₃, Со/SiO₂ and Co/TiO₂ were investigated in the temperature range of 77 ÷ 290 K. Electric properties of FMNC were fitted by formula ρ =ρ₀exp(T₀/T)n with best fit corresponds to the value of n≈1/2. It has been shown that the value of the characteristic temperature T₀ depends from the concentration of Co and proportional s/d, where s is separations between NPs and d is the diameter of NPs. We have shown, that the temperature dependence of thermoelectric power is well described by an empirical formula α(T)~Tt/T+T where m weakly depends from concentration of Co and the superparamagnetic state of Co nanoparticles, and Tt correlated with characteristic temperature T₀.

References


1. G.V. Lashkarev, M.V. Radchenko, M.E. Bugaiova, O.E. Baibara, V. Knoff, T. Story, Y.A. Stelmakh, L.A. Krushin- skaya, M. Foltyn, A.I. Dmitriev, Giant Thermoelectric Power in Co/Al2O3 Ferromagnetic Nanocomposites Below Percolation Threshold, Phys. Stat. Sol. (b), 2017, V. 254, P.1700153. 2. Lashkarev, M. V. Radchenko, O. E. Baibara, M. E. Bugaiova, L.I. Petrosian, Y. Dumond, T. Story, W. Knoff, N. Nedelko, A. Ślawska-Waniewska, M. Foltyn, Y. A. Stelmakh, L. A. Krushynskaya, Nontrivial phenomena in magnetic nanocomposites Co/Al2O3 and Co/SiO2, Low Temp. Phys., 2019, V. 45, P. 228.



A new approach to the obtaining of Y₂O₃ optical ceramics with submicron grain size


Dariia Chernomorets1,2, Vojtěch Nečina3, Andreana Pinacastelli2, Pietro Galizia2, Jan Hostaša2

dariiachernomorets@gmail.com

1Institute for Single Crystals of NAS of Ukraine, Ukraine

2CNR-ISSMC, 64 Via Granarolo, 48018 Faenza (RA), Italy

3Department of Glass and Ceramics, University of Chemistry and Technology, Czech Republic

Y₂O₃ ceramics can be used as IR-transparent material due to its excellent properties. The transparency of ceramics is ensured by the absence of defects, and the necessary mechan- ical properties can be achieved by limiting the grain size [1]. Traditional approaches to the obtaining of such materials, i.e. hot pressing and vacuum sintering, lead to the grains’ growth up to hundreds of microns [2]. Sintering aids, such as ZrO₂, reduce the grain size by an order of magnitude, which is not enough for some applications [3]. Solving the prob- lem is possible with the simultaneous application of spark plasma sintering, as well as ZrO₂. The conditions for the formation of Y₂O₃ optical ceramics with an average grain size of less than 200 nm have been determined for the first time. Initial Y₂O₃ nanopowders doped with 0-15 mol.% ZrO₂ were obtained by high-energy milling, optical ceramics were synthesized by spark plasma sintering at 1500 °C for 10 min at 80 MPa. It is shown that the addition of ZrO₂ as a sintering aid leads to the formation of a homogeneous, almost non-porous mi- crostructure. A significant decrease in the ceramic grain size is observed from 7.4 μm for pure Y₂O₃ to <200 nm for doped ceramics. According to XRD data, no secondary phases were detected, which is consistent with SEM results and indicates the formation of a solid solution of composition (Y₁₋ₓZrₓ)₂O₃. An increase in the concentration of zirconium oxide leads to a decrease in lattice parameters due to the replacement of Y³⁺ ions by Zr⁴⁺ ions, which have a smaller ionic radius. It was found that the Vickers microhardness increases from 7.1 for undoped yttrium oxide ceramics to 11.2 GPa for Y₂O₃ with 15 mol.% ZrO₂. The conditions for the formation of transparent Y₂O₃ ceramics, characterized by an average grain size of <200 nm and a transmittance of 82% at a wavelength of 5 μm (3 mol.% ZrO₂, T=1500 °С, t=10 min), were determined.

References


1. D. Chernomorets, et al., Effect of Milling Parameters on the Morphology and Sinterability of the Yttrium Oxide Powders for Transparent Ceramics, Open Ceram., 2023. V.15, 100391. 2. L. Wen, et al., Synthesis of Yttria Nanopowders for Transparent Yttria Ceramics, Opt. Mater., 2006. V.29, P.239-245. 3. X. Hou, et al., Study on the Effect and Mechanism of Zirconia on the Sinterability of Yttria Transparent Ceramic, J. Eur. Ceram. Soc., 2010. V.30, P.3125-3129.



Boron carbide based tungsten containing sandwich composites as neutron shield materials


Levan Chkhartishvili1,2, Natia Barbakadze3, Otar Tsagareishvili2, Archil Mikeladze2, Mat- lab Mirzayev4,5, Oliko Lekashvili3, Ketevan Kochiashvili3, Roin Chedia2,3

levanchkhartishvili@gtu.ge

1Georgian Technical University, Georgia

2Ferdinad Tavadze Metallurgy and Materials Science Institute, Georgia

3Ivane Javakhishvili Tbilisi State University, Petre Melikishvili Institute of Physical and Organic Chemistry, Georgia

4Institute of Radiation Problems, Azerbaijan

5Western Caspian University, Innovation and Research Center, Azerbaijan

Nuclear power industry requires structural materials that effectively absorb neutron radi- ation. For this purpose, boron and boron-rich compounds and, in particular, boron carbide B4C and its composites are widely used. Both theoretically (see, e.g., [1, 2]) and experimen- tally (see, e.g., [3, 4]) it has been shown that one such promising class of materials is boron carbide compositions with tungsten B4C–W: tungsten phase inclusions containing heavy W atoms provide effective attenuation of the secondary gamma-radiation that accompany the absorption of primary neutrons by the boron 10B isotope atoms. Composites with sand- wich and poly-sandwich morphologies – W/B4C/W, W/B4C/W2B5, W2B5/B4C/W2B5, etc.

– in which boron carbide layers alternate with metallic tungsten and/or tungsten boride ones, were produced and investigated. Surface metallization of boron carbide crystals or grains with tungsten (a) powder, (b) plate or (c) coating (formed by peroxpolytungstic acid aqueous solution treatment at 600°C in hydrogen flow) was done by SPS (Spark-Plasma Sintering) at temperature of 1300–1700°C and pressure of 20–40 MPa for 6–10 min. Such layered composites were also obtained by standard thermal sintering at temperature of 1300–1500°C in argon atmosphere or vacuum of the components bonded with organic compounds aqueous solutions containing 0.5–1% boric acid. SEM (Scanning Electron Microscopy) structural-morphological, XRD (X-Ray Diffraction) phase- and EDS (Energy Dispersive Spectrometry) chemical-compositions analysis of the obtained samples has es- tablished that transition layers of pentaboride W2B5 are formed on the boron carbide– tungsten interfaces, which ensures component-layers strong bonding.

References


1. L. Chkhartishvili. In: Nanostructured Materials for the Detection of CBRN (Eds. J. Bonca, S. Kruchinin), 2018, Dordrecht, Springer Science, Ch. 11, P. 133-154. 2. B. R. Evans, J. Lian, W. Ji. Ann. Nucl. Energy, 2018, V. 116, P. 1-9. 3. S. C. Ozer, B. Buyuk, A. B. Tugrul, S. Turan, O. Yucel, G. Goller, F. C. Sahin. In: TMS 145th Ann. Meeting Suppl. Proc., 2016, Cham, Springer Int. Publ., P. 449-456. 4. L. Chkhartishvili, R. Chedia, O. Tsagareishvili, M. Mirzayev, Sh. Makatsaria, N. Gogolidze, N. Barbakadze, M. Buzariashvili, O. Lekashvili, I. Jinikashvili. In: Proc. 9th Int. Conf. Exh. Adv. Nano Mater., 2022, Victoria, IAEMM, P. 1-15.



Simulation of densification of ceramic materials based on boron carbide during high-speed sintering under pressure


Anatoliy Maystrenko, Vasyl’ Dutka, Vitaliy Kulich, Oleksandr Borymskyi

vadutka@ukr.net


V. Bakul Institute for Superhard Materials, Ukraine


Material properties and strength characteristics of ceramic materials, obtained in a result of sintering under pressure, significantly depends on their density. The sintering regime parameters as well as grain growth affect the density of the sintered material. In order to achieve high density, it is necessary to minimize grain growth. Therefore, it is important to predict the evolution of the sample material density and grain growth at the final sin- tering stage. At the present, a number of densification models of ceramic powders during sintering under pressure have been developed. For the application of these models, it is important to determine their parameters. One of the densification models is the Skorohod- Olevsky model. Since the densification process of powder samples by high-speed sintering under pressure (HSSP) is very fast, the creep of the crystal lattice and grain boundaries can be considered as the dominant densification mechanism. Hence, the densification model can be limited to only the component that describes the mechanism of generalized creep. Therefore, the number of model parameters that need to be identified for simula- tion of densification is reduced. The purpose of this work is to apply a linear regression approach to determine the parameters of Skorohod-Olevsky densification model of pow- der samples based on boron carbide during HSSP according to experimental data, and to model the powder materials compaction using these parameters. The parameters of mate- rial densification model were determined using the results of HSSP-experiments with two compositions based on boron carbide. A computer model of the densification of viscous porous materials was developed, taking into account grain growth. Modeling of the den- sification of powder materials during HSSP-process was carried out. It is shown that at noticeable grain growth of the sample material during HSSP, in order to obtain a dense composition it is necessary to increase the holding time.

References


1. C. Manière, et al., A predictive model to reflect the final stage of spark plasma sintering of submicronic α-alumina, Ceramics International (2016), http://dx.doi.org/10.1016/j.ceramint.2016.0. 2. Skorohod V.V. Rheo- logical basis of the theory of sintering, Kyiv, Naukova Dumka, 1972. 152 p. 3. Olevsky E. A. Theory of sintering: from discrete to continuum. Materials Science and Engineering, 1998. R23. P. 41–100.



Simulation of densification of ceramic materials based on boron carbide during high-speed sintering under pressure


Anatoliy Maystrenko, Vasyl’ Dutka, Vitaliy Kulich, Oleksandr Borymskyi

vadutka@ukr.net


  1. Bakul Institute for Superhard Materials, Ukraine


    Strength characteristics of ceramic materials, obtained in a result of sintering under pres- sure, significantly depends on their density. The sintering regime parameters as well as grain growth affect the density of the sintered material. In order to achieve high density, it is necessary to minimize grain growth. Therefore, it is important to predict the evolu- tion of the sample material density and grain growth at the final sintering stage. At the present time, a number of densification models of ceramic powders during sintering under pressure have been developed. For the application of these models, it is important to de- termine their parameters. One of the densification models is the Skorohod-Olevsky model. Since the densification process of powder samples by high-speed sintering under pressure (HSSP) is very fast, the creep of the crystal lattice and grain boundaries can be considered as the dominant densification mechanism. Hence, the densification model can be limited to only the component that describes the mechanism of generalized creep. Therefore, the number of model parameters that need to be identified for simulation of densification is re- duced. The purpose of this work is to apply a linear regression approach to determine the parameters of Skorohod-Olevsky densification model of powder samples based on boron carbide during HSSP according to experimental data, and to model the powder materials compaction using these parameters. The parameters of material densification model were determined using the results of HSSP-experiments of powder samples with two composi- tions based on boron carbide. A computer model of the densification of viscous porous materials was developed, taking into account grain growth. Modeling of the densification of powder materials during HSSP-process was carried out. It is shown that at noticeable grain growth of the sample material during HSSP, in order to obtain a dense composition it is necessary to increase the holding time. It is also shown that in this case, one of the alternatives to increasing the exposure time is the increasing of the working pressure.

    References


    1. Manière C., Durand L., Weibel A., Estournès C. Spark-plasma-sintering and finite element method: from the identification of the sintering parameters of a submicronic α-alumina powder to the development of complex shapes. Acta Mater. 2016. 169–175. http://dx.doi.org/10.1016/j.actamat.2015.09.003. 2. Manière C., Durand L., Weibel A., Estournès C., A predictive model to reflect the final stage of spark plasma sintering of submicronic α- alumina. Ceramics International, 2016, P. 1–4. http://dx.doi.org/10.1016/j.ceramint.2016.02.048i. 3. Skorohod

V.V. Rheological basis of the theory of sintering, Kyiv, Naukova Dumka, 1972. 152 p. 4. Olevsky E. A. Theory of sintering: from discrete to continuum. Materials Science and Engineering, 1998. R23. P. 41–100.



Electrical conductivity of nanocomposite FexOy(Fe)/SiO2(Si) films


Olha Pylypova1, Oleh Bratus’2, Anatoliy Kizjak2, Serhii Antonin2, Yaroslav Muryi1, Anatoliy Evtukh2,1

olha.pylypova@knu.ua

1Institute of High Technologies, Taras Shevchenko National University of Kyiv, Ukraine

2V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

Nowadays the synthesis and investigation of the materials, containing metal and semicon- ductor nanoparticles in amorphous matrix are of the great interest for the material engi- neering and also various applications. Particular attention is given to the nanocomposites in which nanosized particles of soft ferromagnetic alloys are randomly distributed in di- electric matrix [1]. The investigation of electrical conductivity and its dependence on the technological processes is еру necessary condition for many applications. The nanocom- posite FexOy(Fe)/SiOx films were deposited by Ion Plasma Sputtering (IPS) technique at sputtering of combined silicon-iron target in O2+Ar ambient at 150 °C on Si substrates. Among the varying parameters of deposition process were ratio of Fe and Si parts of tar- get, content O2 in gas mixture, and film thickness. In the second stage, FexOy(Fe)/SiOx films were annealed in the argon atmosphere at the temperature of 1100 °C during 60 min to form nanocomposites. Current-voltage characteristics of MIS structures contain- ing FexOy(Fe)/SiO2(Si) films were measured in the temperature range of 95–340 K using the Source Meter 2410 Keithley. As a result of the study of the electrical characteristics of nanocomposite films on direct current, it was established main pequliarities of electron thatsport through the nanocomposite FexOy(Fe)/SiO2(Si) films.For all films under investi- gation the current for non-annealed films is smaller than for annealed ones in the region of the applied electric fields E < 2.0×106 V/cm, but the ratio becomes the opposite with the in- crease of the applied fields higher E > 2.0×106 V/cm.Some electron transport mechanisms are realized in dependence on the applied electric field, namely: quadratic current-voltage dependence, the Child-Langmuir law, space charge limited current with shallow traps in bandgap, Poole-Frenkel and Fowler-Nordheim mechanisms.

Acknowledgments


This research was supported by the project “Development of nanocomposite material technology for highly efficient absorption of electromagnetic radiation” of the National Research Foundation of Ukraine (No. 2022.01/0066).

References


1. Kizjak, A. Y., Evtukh, A. A., Bratus, O. L., Antonin, S. V., Ievtukh, V. A., Pylypova, O. V., and Fedotov, A. K. (2022). Electron transport through composite SiO2 (Si) and FexOy (Fe) thin films containing Si and Fe nanoclusters. Journal of Alloys and Compounds, 903, 163892.



3D printing of heaters based on MoSi2 by Robocasting method


Vladyslav Naumenko, Nina Zyatkevich, Dmytro Vedel, Oleksandr Derev’yanko, Roman Lytvyn, Oleksandr Myslyvchenko, Ostap Zgalat-Lozynskyy

v.naumenko@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


One of the main directions of 3D printing is obtaining products of complex shapes to re- place worn or damaged analogues. Modern analytical equipment for heat treatment of materials is produced in small batches and contains heating elements of complex shapes. Replacing these heating elements is an expensive and complicated process. Using modern 3D printing technologies, such as the Robocasting method, it is possible to print products of complex shapes from a material similar to that used in the device, or even better, [1,2]. In our work, we investigated the process of manufacturing heaters of complex shapes based on MoSi2, from the preparation of pastes for 3D printing using the Robocasting method to their consolidation and determination of the characteristics of the obtained heating ele- ments. The shapes of the heating elements were obtained using the Robocasting method. This involved employing layer-by-layer printing on the Ender 5 printer with the Stoneflower 2 ceramic module and using a paste based on MoSi2 powder. A study of the rheological properties of pastes based on molybdenum disilicide and synthetic rubber with gasoline as a binder was conducted. It was established that the print scale (nozzle/filament diameter) depends on the content of the plasticizer. The smaller the nozzle, the greater the content of plasticizer required to obtain a high-quality product shape closest to a digital twin. Several samples of different forms were printed using Robocasting technique. Printed forms were heat-treated in a vacuum drying chamber at a temperature of 400° for 2 hours. Sintering was carried out in the high temperature vacuum furnace at 1900°C, holding time - 1 hour. After sintering, the residual porosity of the samples is 15-17%. The Vickers hardness of the samples was 9.5±1.4 GPa. When determining the current-voltage characteristic, the heater was heated to a temperature of about 90°C at a power of 1 W.

Acknowledgments


The work the was done as part of the joint UKRAINIAN-GERMAN R&D project ”Machine Learning Enhanced Additive Manufacturing”

References


1. Zgalat-Lozynskyy, O.B. Materials and Techniques for 3D Printing in Ukraine (Overview). Powder Metall Met Ceram 61, 2022, p.398–413 2. Vladyslav Naumenko, Ostap Zgalat-Lozynskyy, Dmytro Zyatkevych, 3D printing of the ceramic materials based on Mo₀.₉Cr₀.₁Si₂ by Robocasting technique. Book of Abstracts, 8th International Materials Science Conference HighMatTech-2023, p. 17. October 2-6, 2023 Kyiv, Ukraine



Artificial intelligence optimization method for nuclear fuel triso-elements in high-temperature reactor


Аlexander Kul’ment’ev

kulmentev@ukr.net


Institute of Applied Physics of NAS of Ukraine, Sumy


In the present era nuclear energy, has unique advantages compared to other energy sources. Now significant research and development related to TRISO-coated fuels is underway worldwide as part of the activities of the Generation IV International Forum on Very-High-Temperature Reactors. The focus is largely on extending the capabilities of the TRISO-coated fuel system for higher operating temperatures (1250°C) and higher burnups (10 – 20 %). Of greatest concern is the influence of higher fuel temperatures and burnups on fission product interactions with the SiC layer leading to the release of fission products. One of the possible solution consist in addition additional layers with special properties. For example, to prevent the corrosion of the SiC layer by fission product palladium, several types of new combinations of the coating layers have been proposed and tested. The idea is to add a layer that traps palladium by chemical reaction inside the SiC layer. Earlier several kinds of additional layers have been selected: an SiC + PyC layer and an SiC layer. For optimization of TRISO particle it is necessary to determine the number of additional layers, their thickness and composition. This is combinatorial optimization problem (continuous + discrete). Traditional methods rely on manual adjustment and human experience, which is inefficient and difficult to obtain the optimal solution. Therefore it is necessary to develop an automated design method. In the present report variant of such method is proposed based on artificial intelligence approach. There are several meta-heuristic algorithms such as genetic algorithm, neural network and particle swarm optimization algorithm (PSO) which have the ability to solve continuous, discrete and combinatorial optimization problems. Namely PSO algorithm looks especially attractive. Early this method was proven to be reliable and effective in nuclear power problems by applying it in designing a Savannah marine reactor shielding.

References


1.Wrochna G, Fütterer M, Hittner D., Nuclear cogeneration with high temperature reactors, EPJ Nucl. Sci. Tech- nol., 2020. V.6, N31. P.7. https://doi.org/10.1051/epjn/2019023. 2. R. Eberhart, J. Kennedy, Particle swarm optimization, in: Proceedings of the IEEE International Conference on Neural Networks, 1995. Citeseer. 3.

  1. Wu, et al., Multi-objective optimization method for nuclear reactor radiation shielding design based on PSO algorithm, Ann. Nucl. Energy, 2021. V.160.



    SPS of conductor–insulator system close to percolation threshold based on Si3N4–ZrN


    Bohdan Pokhylko, Valerii Kolesnichenko, Andrey Ragulya

    b.pokhylko@ipms.kyiv.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    There is a difference in how conductive and insulating materials are heated during Spark Plasma Sintering (SPS) [1]. Conductive materials can be additionally heated by Joule heat- ing, which may cause changes in shrinkage behaviour and structure evolution [2]–[3], and even thermal runaway [3]–[4]. It may be especially crucial for the conductor-insulator system which can drastically turn from insulator to conductor during SPS due to poros- ity reduction to a certain level called percolation threshold [5]. SPS of (Si3N4–30vZrN)– 5vY2O3, SEM analysis of powders and sintered samples were carried out. To regulate the current density in the powder, combinations of die and powder were isolated from the current flow by applying an insulating coating (BN). A rapid rise in current indicators was observed when the die was isolated. It is assumed to be caused by the drop in powder resistivity after reaching the percolation threshold. In contrast, other isolation schemes with no applied isolation and isolation of both the powder and the die show nearly linear dependences. SPS with the isolated die appears to be more sensitive to the change in the powder conductivity due to concentrating most of the current in the powder instead of the die. The application of higher current density in the powder caused a lowering of the temperature at which shrinkage began up to 60 °C, and the shrinkage intensification at the final stage up to 2 times. The calculations of the resistance of the electric circuit of die and powder with different combinations of isolation of die and powder proved it. Displacement of punches, changes in height and conductivity of the powder sample were considered. The derived equation allows to evaluate the change in the powder conductivity during sintering. Therefore, SPS with the isolated die is quite a useful technique for the investigation of conductor-insulator systems with the percolation threshold.

    References


    1. V.V. Krizhanovskiy, V.I. Mali, Calculation of the Temperature Distribution in Cylindrical Samples of Alumina and Copper Produced by Spark Plasma Sintering, Ceramics, 2021, V. 4, P. 437–446. 2. Fei Chen, Shuang Yang, Junyan Wu et al., Spark Plasma Sintering and Densification Mechanisms of Conductive Ceramics under Coupled Thermal/Electric Fields, J. Am. Ceram. Soc., 2014, V. 98, P. 732–740. 3. C. Manière, G. Lee, E.A. Olevsky, All-Materials-Inclusive Flash Spark Plasma Sintering, Sci. Rep., 2017, V. 7, № 15071. 4. I. Mazo, B. Palmieri,

      1. Martone et al., Flash sintering in metallic ceramics: finite element analysis of thermal runaway in tungsten carbide green bodies, JMR and T, 2023, V. 23, P. 5993–6004. 5. K. Vanmeensel, A. Laptev, O. Van der Biest, J. Vleugels, The influence of percolation during pulsed electric current sintering of ZrO2–TiN powder compacts with varying TiN content, Acta Mater., 2007. V. 55, P. 1801–1811.



        Determination of the mechanical properties of a composite material based on silicon nitride by the indentation method


        Oleksandr Lukyanov, Svitlana Chugunova, Victor Melnyk, Iryna Goncharova

        oleksandrlukanov8@gmail.com


        Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


        The purpose of the research was to determine the mechanical characteristics of silicon ni- tride ceramics and establishing optimal cutting regime of tool material. The composition (Si3N4+5%Al2O3+30%TiN) used for the manufacture of cutting tools were investigated. This composite was obtained by hot pressing of technical β-modification silicon nitride with an initial grain size of 0.6-1 μ with the addition of Al2O3 oxide to activate sinter- ing and titanium nitride TiN in order to reduce the brittleness of the composite [1]. It was determine the following mechanical properties: Vickers hardness (HV), Knoop hard- ness (HK), fracture toughness K1C and plasticity characteristic δН. For brittle material, the use of the Knoop indenter allows to obtain high-quality indentation without chipping and cracks, which increases the accuracy of hardness measurement. To characterize the material’s resistance to brittle fracture, the K1C value is used, which was determined by the indentation method based on the length of cracks that appear near the corners of the Vickers hardness indenter, and the value of δH was calculated from hardness measure- ments. The researched composite at room temperature has the following characteristics: HV=17,5GPa, НK=16,8GPa, K1С=8,35MN/m3/2, δН=0,52. To relieve internal stresses that are formed in ceramics during sintering due to different values of CTE (coefficient of thermal expansion) for Si3N4 and TiN, the composite was annealed at a temperature of 1050°C. After annealing, the mechanical characteristics remained at a fairly high level: HV=16GPa, НK=14GPa, K1С=7,4MN/m3/2, but δН increased to 0.55. Chipping of the edges of the cutting tool wasn’t observed. The research was carried out on the influence of cutting conditions on the mechanical characteristics of the tool. For hardened steel tools, the optimal regimes of cutting with silicon nitride ceramics were determined: t=0.02 mm, and S=0.5 mm/pass.

        References


        1. Gnesin G., Osipova I., Preparation and properties of tool materials based on silicon nitride, International Conference on Powder Metallurgy, Dresden, 1977, pp. 1-45 .



          Effect of high hydrostatic pressure treatment of cememted carbides WC-3Co, WC-6Co, and WC-15Co on their Vickers hardness


          Gennadiy Akimov1, Vitalii Sheremet2, Ihor Andreev1, Petro Loboda2, Iryna Trosnikova2

          v.sheremet@kpi.ua

          1V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

          2National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

          The experimental study is devoted to the investigation of the influence of high hydrostatic pressure (HHP) compression of tungsten carbide and cobalt carbide-based cemented car- bides on their properties. The samples WC-3 wt.% Co, WC-6 wt.% Co, and WC-15 wt.% Co were investigated. Vickers hardness was measured. The following results were obtained. Compression of HHP at 400MPa leads to a decrease in Vickers hardness of WC-3 wt.% Co by 8%, WC-6 wt.% Co by 5%, and WC-15 wt.% Co by 5%. Using SEM, cracking of large grains of tungsten carbide in Vickers indenter imprints was found in all samples treated with HHP. It is concluded that cracking and hardness decrease are mainly due to the well- known fact that the compressibility of Co is more than twice as high as that of WC [1]. It is suggested that the different compressibility of WC and Co could change the coherence fraction of the two materials at their boundary and cause residual stress along the bound- ary and in the regions of WC and Co adjacent to the boundary after HHP removal. These stresses could cause cracking of WC grains, and cracking of grains entailed a decrease in hardness.

          References


          1. V. A. Mukhanov, O. O. Kurakevych, V. L. Solozhenko, The interrelation between hardness and compressibility of substances and their structure and thermodynamic properties, J. Superhard Mater., 2009, V. 30, No. 6, P. 368–378.



          Deformation-induced polymorphic transformation of β-SiС


          Oleksandr Radchenko, Kazbek Gogaev, Oleg Grigoriev, Mykola Bega, Artur Stepanenko,

          Anatoliy Itsenko

          arradch@gmail.com


          Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


          At different temperatures and pressures, some chemical compounds have different types of crystal structures or modifications, the stability of which is determined by the minimum thermodynamic potential [1]. Deformation of the material puts it in a less stable state and can cause polymorphic transformation [2,3]. Silicon carbide has two main modifica- tions - β-SiC (low-temperature - cubic) and α-SiC (high-temperature - hexagonal) [4]. The transition temperature is 2100°C. Transformation under pressure was not investigated. Tapes were rolled from β-SiC powder to the maximum density (rolls with a diameter of 40 mm from the rolling mill had zero exit gap). The maximum normal contact stress did not exceed 0,7 GPa, the temperature did not exceed 40°С. Presses with a diameter of 15 mm were obtained from the original powder and crushed rolling stock. The density of the pressings was 1.05 and 1.23 g/mm3, respectively. The diffraction curves of the samples were taken in discrete scanning mode on a DRON-ZM diffractometer in monochromatized Cu-Kα radiation. The ratio of the atomic radii of carbon and silicon does not allow obtain- ing simple dense spatial structures [5]. Quantitative analysis of the phase composition of the powders performed using the software package Powdercell 2.4 showed that the phase composition before rolling was ~ 95% β-SiС and ~ 5% α-SiС, while after rolling - ~ 95% α-SiС and ~ 5% β -SiС. The integral width of the α-SiС lines obtained after rolling is signif- icantly greater than the similar characteristic (26 - 46%) in the α-SiС powder supplied by the same company (Qinhuangdao Eno High-Tech Material Development Co. LTD, Китай). Results of X-ray phase analysis of granules from powders | β-SiС and strips rolled at the maximum load showed that polymorphic transformation of β-SiС into α-SiС took place dur- ing rolling.

          References


          1. Materials science: Textbook for universities. B.N. Arzamasov I.Y. Sydoryn, G.F. Kosolapov and others; Under community ed. B.N. Arzamasova. M.: Mashinostroenie, 1986. – 384 с. (In Russia). 2. Sauvage X., Chbihi A., Quelennec X. Severe plastic deformation and phase transformations. Journal of Physics: Conference Series 240 (2010) 012003 doi:10.1088/1742-6596/240/1/012003 3. Kozak L.Yu., Kozak O.L. Polymorphic transformations and plasticity / Solid state physics and chemistry. V. 13, № 3 (2012) С. 759-765. (In Ukraine) 4. L.O. Biryukovich. Crystal chemistry of refractory compounds: academic. manual / L. O. Biryukovich. – К.: НТУУ «КPІ», 2016. – 112 p. (In Ukraine) 5. Samsonov G.V. Properties of elements. Physical properties. T.1. Edited by G.V. Samsonov/ Directory. - 2nd ed. - M.: Metallurgy, 1976. – 600 p. (In Russia)



          Phase Relation of the ZrO2–HfO2–La2O3 System at 1500-1100 DC


          Yuriy Yurchenko1, Oksana Korniienko1, Sergey Korichev1, Anatoliy Sameljuk1, Hanna Barchevska1, Irina Subbota2

          kornienkooksana@ukr.net

          1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

          2National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

          Complex oxides such as the rare-earth zirconate and hafnate ceramic materials in the fluorite-type (space group Fm3m) and/or pyrochlore-type structure (space group Fd-3m) display a variety of interesting and promising physical, chemical, thermal and magnetic properties which render them excellent candidates in applications such as thermal barrier coatings, solid electrolytes, materials for nuclear industry, and are of interest as lumines- cent materials, scintillators for applications in radiation detectors and others. The phase diagrams of multicomponent systems are the theoretical basis for the creation of new func- tional and structural materials. In the presented work, for the first time phase equilibria and physicochemical properties of phases formed in the ZrO2–HfO2–La2O3 ternary system at a temperature of 1500, 1250 and 1100 °C (in the air) in the entire concentration range were researched using powder X-ray diffraction and microstructural analysis. The samples were prepared with a concentration step of 1-5 mol.%. X-ray diffraction analysis (XRD) of the samples was performed by the powder method on the DRON-3 device at room temper- ature. The scanning step was 0.05-0.1 degrees, the exposure was 4 sec. in the 2 angles range from 10 ° to 100°. In the present work, phase equilibria in the ZrO2–HfO2–La2O3 ternary system have been studied, and isothermal sections of this system at temperatures of 1500 1250 and 1100 °С were constructed. It was found that, at these temperatures, the formation of new compounds in the studied system is not observed. The studied isothermal sections are characterized by the formation of a continuous series of solid solutions based on an ordered phase with a pyrochlore-type structure. It was found that the isothermal sections of the state diagram of the ZrO2–HfO2–La2O3 system at 1500 and 1250 °C are characterized by the existence of four two-phase regions (A+Py, Py+T, Py+M, T+M) and one three-phase region (Py+T+M).

          References


          1. Lakiza S. M., Hrechanyuk M. I., Red’ko V. P., Ruban O. K., Tyshchenko J. S., Makudera A. O., Dudnik O. V. The Role of Hafnium in Modern Thermal Barrier Coatings. Powder Metallurgy and Metal Ceramics, 2021; 60:1–2, 78–89. https://doi.org/10.1007/s11106-021-00217-1 2. Borges F. H., Silva da Hora Oliveira D., Hernandes G. P., Ribeiro S. J. L., Gonçalves R. R. Highly red luminescent stabilized tetragonal rare earth-doped HfO2 crystalline ce- ramics prepared by sol-gel. Optical Materials: X, 2022; 16, 100206. https://doi.org/10.1016/j.omx.2022.100206 3. Gupta S. K., Zuniga J. P., M. Abdou, Thomas M. P., M.De A. Goonatilleke, B. S. Guiton, Mao Yu. Lanthanide-doped lanthanum hafnate nanoparticles as multicolor phosphors for warm white lighting and scintillators // Chemical Engineering Journal – 2020– Vol. 379 – P.122314. https://doi.org/10.1016/j.cej.2019.122314



          Ab initio study of the effect of substitutional impurities Mo and C on the physico mechanical characteristics of Zr(1-x)Mo(x)B2(1-y)C(2y) solid solutions


          Nataliia Rozhenko, Liubov Ovsiannikova, Valerii Kartuzov

          rzh.natali@gmail.com


          Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


          Zirconium diboride is a promising material for creating ultra-high temperature ceramics (UHTK), since it is characterized by a high melting point, resistance to oxidation and ther- mal shock, and thermal conductivity. Varying substitutional impurities allows you to con- trol the properties of ZrB2-based UHTK. An approach for calculating the values of the bulk modulus (B) and hardness of single crystals (HV) of solid solutions based on ZrB2 with substitutional impurities of Mo and/or C based on the results of an Ab initio study of iso- lated atomic clusters – fragments of their structure – has been developed and applied. The constructed clusters containing 19, 20, 45 and 87 atoms were studied within the DFT meth- ods using Gaussian or GAMESS complexes. Within the developed approach, the cohesion energy of isolated clusters, obtained from first principles, is of decisive importance. The values of B and HV, calculated from the results of Ab initio studies of fragments of various geometries of the ZrB2 structure without impurities, turned out to be B = 197-219 GPa and HV = 22.3-24.8 GPa. The calculation results are in full agreement with experimental data B=218-250 GPa and HV=21.9-27.1 GPa. According to calculations carried out for the Zr(1-x)Mo(x)B2 at x={1/14, 1/6, 1/3, 4/9}, an increase in the Mo fraction contributes to an increase in the B by 2–13% and HV by 4–20% compared to ZrB2. For ZrB2(1-y)C(2y) at y={1/12, 1/8, 1/6, 1/3, 3/8} it is established that the greatest increase in B and HV achieved at y=1/8 (6% and 10% respectively). For the Zr(1-x)Mo(x)B2(1-y)C(2y) compound with both impurities, the largest increments are achieved at x=y=1/6 and amount to 12 and 20 (%) of the B and HV, respectively. The results obtained are in full agreement with available experimental data [1], [2], which means successful validation of the developed approach and its ability to adequately predict the values of the bulk modulus and hardness of new prognosticated ZrB2-based solid solutions.

          Acknowledgments


          This work is supported by the NATO Science for Peace and Security Programme, Project G5773.


          References


          [1] O. N. Grigoriev, B. A. Galanov, A. V. Koroteev, L. M. Melach, T. V. Mosina, N. D. Bega, V. A. Kotenko, V.

      2. Vinokurov, L. I. Klimenko, A.V. Stepnenko, Zirconium diboride with sintering additives structure formation and mechanical properties, Electron Microscopy and Strength of Materials - Kiev: Frantsevich Institute for Prob- lems of Materials Science NASU, 2015, No.21, P. 110-127. [2] D. Vedel,A. Osipov,L. Melakh,M. Brodnikovskyi,O. Grigoriev, Contact interaction and hot pressing of ZrB2-MoSi2 in CO/CO2 atmosphere, Journal of the European Ceramic Society, , 2023, V. 43, No. 8, P. 3025-3033. https://doi.org/10.1016/j.jeurceramsoc.2023.02.006.



Electrical Resistivity of AlN-hBN-TiB2 Ceramic Composite


Vadym Omelianenko, Igor Fesenko, Oksana Kaidash, Nina Sergienko

igorfesenko@ukr.net fesenko.ihor.p@gmail.com


  1. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


    Dielectric matrix ceramic composites based on high thermal conductivity AlN are impor- tant for engineering of new electronic devices with lower operation temperature. Com- posites of AlN dielectric matrix with electroconductive inclusions of TiB2 have been pre- pared and investigated with the aim to establish their electrical resistivity for possible applications. The ceramic composites AlN–hBN–TiB2 have been prepared by hot pressing (T=1950 °С, P=30 MPa) with TiB2 content from 45 to 66 wt.%. The four-probe electri- cal resistivity measurements of as-obtained specimen at room temperature showed corre- spondingly values between 1.0•10–5 and 0.2•10–5 Ohm•m. The observed relatively small decrease of electrical resistivity of the hot-pressed AlN–hBN–TiB2 system composite for increasing conductive phase content by 21 wt.%, and when conductive phase content is higher than a percolation threshold may testify in favor of a tunnel character of charge transfer, discussed in [1]. Addition of hBN under mixing of the starting powder system may form an additional dielectric layer at the surface of the conductive particles (TiB2). Thus a tunnel mechanism of charge transfer in the hot-pressedAlN–hBN–TiB2 ceramic composites may dominate in a wide region of concentrations including the percolation threshold.

    References


    1. Baibara O., Radchenko M., Ievtushenko A. et al. Features and theoretical analysis of electric and thermoelec- tric properties of Co/Al2O3, Co/SiO2 and Co/TiO2 ferromagnetic nanocomposites in the low-temperature region. HighMatTech–2023, October 2-6, 2023, Kyiv, Ukraine, Book of Abstracts, P. 34.



Mechanical behavior of SOFC electrolytes based on zirconium dioxide


Mykola Brychevskyi

m.brychevskyi@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The materials based on zirconium dioxide are popular to using for high-temperature SOFCs[1]. In particular, there are occurs due to flexibility of phase and structural changes and opportunity of symmetry raising by replacing the four-valent zirconium ion with a three- or five-valent ion. This leads to the formation of an additional sublattice of oxygen vacancies [2]. But mechanical behavior is of critical importance too for a carrier-electrolyte technological scheme. Since increased mechanical properties allow to manufacturing of thinner electrolyte, which will proportionally reduce the total resistance as of the component and the device as a whole [3]. Three different starting powders of zirconium dioxide stabilized with 10 mol. % scandium oxide and 1 mol. % cerium oxide were used. One-sided pressing with follow by isothermal sintering in air in the tempera- ture range of 1200-1550 ℃ during 1,5 hours was used to produce of ceramic specimens. The base research methods were biaxial strength studying and SEM of fracture surface. It was shown that using of initial powders to allow producing the various type ceramics with significant structure changes: porosity and sizes of effective structure components, and implement all possible fracture micromechanisms: interparticle, intergrain and cleavage fracture. The produced materials can be classified by changes of structural features with increasing of thermal influence, which are manifested with fracture surface studying. Type I material is porous, has a low recrystallization rate and was fractured exclusively by cleavage. Type II is a dense material, with has a high rerycstallization rate and has fractured by cleavage. Type III material has a high rapid recrystallization rate and intergranular fracture. It was found that the shift of activation energy of densification and grain size grow was taking place in the temperature range of 1300-1400 ℃ and was coincided with the dominant fracture micromechanism changes.

References


1. K. C. Wincewicz, J. S. Cooper, Taxonomies of SOFC material and manufacturing alternatives, J. Power Sources, (2005). 140, pp. 280–296. 2. S. Fabris, A.T. Paxton, M.W. Finnis, A Stabilization Mechanism of Zirconia Based on Oxygen Vacancies Only, Acta Materialia, (2002), 50(20), pp. 5171-5178. 3. O Vasylyev, M Brychevskyi, Y Brodnikovskyi, The structural optimization of ceramic fuel cells, Universal J. of Chem, (2016),4 (2), pp. 31-54.



Effect of chromium carbide on the elastic modulus of modified reaction- bonded silicon carbide


Mykyta Pinchuk1, Mykola Gadzyra1, Ihor Gnylytsia2

pinchukipm14@gmail.com

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2Ivano-Frankivsk National Technical University of Oil and Gas, Ukraine

The study used industrial silicon carbide powders (3, 28, 80, 100) U+03BCm and syn- thesized nano-sized silicon carbide (0.07 U+03BCm) in the form of its solid solution of carbon and chromium carbide with an average particle size of 0.2 U+03BCm. Chromium carbide was synthesized in an induction furnace at 1550 U+00B0 C in an argon atmo- sphere[1]. Chromium oxide and thermo-expanded graphite (TEG) powders were used as synthesis components. X-ray diffraction was performed on an Ultima IV diffractometer in the Bragg-Brentano focusing geometry (CuKU+03B1 - monochromatic radiation, graphite bent monochromator on the diffracted beam). The values of the first-order stresses were determined by the sin2(U+03D5) method for cubic SiC. The measurements at ψ angles of 10, 20, 25 and 30 degrees were performed by the isoinclination method. Thus, the value of the first-order stresses perpendicular to the sample plane along the [311] crys- tallographic direction in cubic β-SiC was obtained. When 3 to 10% of highly dispersed Cr U+2083CU+2082 is introduced into the composition of the initial batch and infiltrated with liquid silicon in an argon atmosphere, a decrease in the modulus of elasticity is observed, followed by its increase in reaction-bonded silicon carbide (RBSC). The minimum on the curve corresponds to a modifier content of 5U+0025, which corresponds to a modulus of elasticity of 260-280 GPa. This dependence was established on RBSC of different ini- tial fractions of industrial silicon carbide, including synthesized nano-sized silicon carbide. X-ray structural studies have established that the modification process with chromium car- bide leads to the occurrence of internal compressive stresses in contrast to the tensile stresses for unmodified RBSC. It is shown that the dependence of internal stresses on the modifier content correlates with the modulus of elasticity. The minimum value of the modulus corresponds to the maximum value of the internal compressive stresses.

Acknowledgments


SiC-based ceramics are mainly produced by free sintering or infiltration of porous silicon preforms with silicon. Hot pressing is not widely used because it is expensive and cannot be used to produce complex shapes.

References


1. Features of the synthesis of chromium carbide using different forms of carbon //Powder Metallurgy.– 2017.–

№9,10.– P. 34-39



Peculiarities of SPS nanostructured ceramics based on Si3N4 in the presence of varying liquid phase amounts


Maryna Zamula, Valerii Kolesnichenko, Nadiya Tyschenko, Oleksandr Shyrokov, Artur Stepanenko, Hanna Borodianska, Andriy Ragulya

m.zamula@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Si3N4 displays excellent tribological and mechanical properties, making it promising for high-temperature applications [1]. To achieve high strength and fracture toughness, the formation of anisometric grains of β-Si3N4 due to polymorphic α→β-phase transformation during sintering of Si3N4 is crucial. This study aims to investigate the phase transfor- mation in Si3N4 and the consolidation of materials using the spark plasma sintering (SPS) method in the presence of varying amounts of liquid phase. The starting mixtures of Si3N4 with varying ratios of oxide additives (1-7wt.% Y2O3 and ~10wt.% SiO2) were prepared by ball milling for 4 hours at 100 rpm [2]. At a SPS temperature of 1800°C, the addition of 1.5wt.%Y2O3 to Si3N4 requires more than 30 min for complete shrinkage. The sample has a remaining open porosity of 6.4%, meaning there is not enough liquid phase for complete densification. Adding 3wt.%Y2O3 allows for consolidation in about 20 min, resulting in almost pore-free ceramics. Adding 7wt.% of Y2O3 reduces the holding time to reach 0% open porosity to 15 min. The analysis of the ceramic microstructure indicates that the av- erage grain size in sintered Si3N4 ceramics increases from 300 to about 500 nm when the quantity of Y2O3 is raised from 1.5 to 7wt.%. This increase in grain size is likely due to a longer exposure time at consolidation temperature. All ceramics have anisometric grains with a length of 1–2μm, corresponding to β-Si3N4 phase. According to the XRD results, no α-Si3N4 phase was detected in any of the sintered samples. However, a significant con- tent (~50vol.%) of the Si2N2O phase was observed. Thus, there is a correlation between the exposure time and the amount of liquid phase formed during sintering, which changes with the amount of Y2O3 additive at a fixed amount of SiO2. Therefore, the significant volume of the liquid phase promotes densification under pressure via the mechanism of rearrangement of Si3N4 nanoparticles to obtain a dense ceramic.

References


1. A.H. Kouchaki Foroshani, A. Faeghinia, S. Seyed Afghahi, S.A. Tayebifard, A. Sedaghat Ahangri Hossein Zadeh, Ceramics International, 2022. 48. P.29782–29789. 2. M.V. Zamula, V.G. Kolesnichenko, A.V. Stepanenko, N.I. Tyschenko, O.V. Shyrokov, H.Yu. Borodianska, A.V. Ragulya, Powder Metallurgy and Metal Ceramics, 2022. 60, No. 11-12. P. 672-684.



On the crack resistance of ceramic composites based on silicon nitride


Vicktor Goncharuk, Boris Galanov, Mykola Iefimov, Irina Goncharova, Vadim Tsivilitsin

i.goncharova@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The work carried out a study of the crack resistance K₁c, calculated theoretically and ex- perimentally determined during mechanical tests, for two systems of ceramic composite materials based on silicon nitride. 1. Electrical materials of the Si₃N₄–SiC system were ob- tained by reaction sintering. The grain size of the base (Si₃N₄) was 1-2 μm, the SiC additive varied in size from 1-5-120 μm and content of 0, 10, 20, 30%. 2. Structural materials of the Si₃N₄–TiN system were obtained by hot pressing. The grain size of the base (Si₃N₄) was 1-2 μm, TiN additive varied in size 1-5-30 microns and content 0, 10, 20, 30, 40, 50%. Based on theoretical concepts [1] the values of crack resistance K₁c of composites with known K₁c values for pure components were determined by calculation. Theoretical concentra- tion dependences of crack resistance were obtained, which are curves with a maximum in the range of additive concentrations of 20-30%. By testing the bending of notched beams for all materials of the Si₃N₄–SiC and Si₃N₄–TiN system (both for pure components and for composites for all concentrations and grain sizes of the additive), the K₁c values were experimentally determined. A fairly good agreement between the experimental and cal- culated values of K₁c was obtained for all materials studied, with the discrepancy being less 5 %. In the case of a coarse-grained additive, the discrepancy between theory and experiment was large. This is explained by the high stress concentration in large grains and, therefore, even a small number of large grains lead to a sharp decrease in K₁c. As a result of the research it was found that physical patterns of changes in the crack resis- tance of composite materials depending on the concentration of components. A fairly good agreement between theory and experiment was obtained using the example of binary sys- tems Si₃N₄–SiC and Si₃N₄–TiN (the discrepancy between the theoretical and experimental values of crack resistance does not exceed 5%).

References


1. B.A. Galanov et al. Theoretical Fundamentals of Ceramic-Matrix Composites. In: Ceramic and Carbon-Matrix Composites. Chapman and Hall, N.Y., London, 1994, p.1-28.



The effect of chromium and molybdenum carbides alloing on corrosion resistance of mesostructure WC-Nі composites in chloride environment


Oleksandr Matviichuk1, Vasyl Vynar2, Vasyl Ivashkiv2, Nadiia Ratska2, Сhrystyna Vasyliv2

o.o.matviichuk@gmail.com

1V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

2Karpenko Physico-Mechanical Institute of NAS of Ukraine, Lviv

Composites of the WC-Ni system are characterized by high wear resistance and crack re- sistance and are used in the sliding friction pairs [1]. Friction pairs based on WC-Ni alloys work well in such not electrically conductive environments as petroleum products and am- monia, but are not corrosion resistant in electrolytes such as chloride-containing solutions. One solution of the problem is to increase the corrosion resistance of the Ni binder. The aim of the work was to study the electrochemical characteristics of the WC-20 wt% Ni mesostructural alloy with the addition of 1%Cr3C2 and 0.5%Mo2C in chloride-containing solutions. The characteristics of corrosion processes were studied in the potentiodynamic mode in solutions: 3% NaCl+0.5% CH3COOH (pH 3), 3%NaCl (pH 7) and 3% NaCl + 0.0004% NaOH (pH 10). It is shown that the modification of the mesostructural alloy WC- 20% wt. Ni by Cr3C2 and Mo2C contributes to shifting the electrode potential to more positive values. Taking into account the pH of the environment, there is an improvement in the potential values for both materials with a shift in the environment pH from 3 to

10. It was established that the corrosion current density of the WC- Ni alloy in a neutral 3% NaCl solution is 1∙10-3 mA/cm2. In alloy with 1%Cr3C2 and 0.5%Mo2C, the current density decreases by almost an order of magnitude and is 5∙10-4 mA/cm2. A similar trend is observed in acidic and alkaline environments. In an acidic environment, the corrosion current density of basic alloy and modified by carbides is 5∙10-3 and 1∙10-3 mA/cm2, in an alkaline environment – 6∙10-4 and 2∙10-4 mA/cm2, respectively. In an environment with a pH3, nickel is oxidized and goes into solution, while in an environment with a pH10, its partial passivation occurs. Therefore, alloying WC-Ni mesocomposition with 1%Cr3C2 and 0.5%Mo2C increases its corrosion resistance in environments with different acidity. The maximum corrosion resistance is observed in an alkaline environment.

References


1.Baranovskii A. M. and Bezruchko A. G., Antifriction materials based on hard alloys of the WСNi type and the experience of their application in heavily loaded sliding friction couples, Instrum. Svit, 2013, No.1(57). P.12– 15.



Ceramic material based on TiB2-FeSi using the reaction sintering method under SPS conditions


Oleksandr Derev’yanko, Tetyana Istomina, Roman Lytvyn, Oleksandr Myslyvchenko,

Dmytro Verbylo, Ostap Zgalat-Lozynskyy

alederevyanko@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


When creating new heterogeneous structural materials based on TiB2, the addition of bind- ing components [1]. This has a positive effect on wear resistance, strength, and crack re- sistance. One of the promising directions for the consolidation of ceramics based on TiB2 is the use of spark plasma sintering (SPS) technology. In order to obtain a ceramic compos- ite material based on the TiB2-FeSi composition, a mixture of powders with a composition (vol. fr.) of 27%TiH1.5-62%TiB2-9%TiSi2-2%Fe was used [2]. The SPS process was per- formed without the use of a protective chamber with a vacuum/gas environment [3]. The total duration of electromechanical processing was 210 s. The required temperature level of 970 С was reached in the first 60 s. The last 150 s was spent isothermally holding at the specified temperature. The total electric current through the mold was constant after 60 s, and was kept at 2.0 kA, as was the temperature. The mechanical load during SPS was at the level of 35-40 MPa. X-ray structural analysis showed a difference in the com- position from the initial one, which was obtained after mixing the components. Vickers HV microhardness measurement at a load of 100g showed an average value at the level of 19.7-22.39 GPa. Rockwell hardness was 75-77 HRC units. Ceramic fracture occurs at

112.2 MPa per bend without, in fact, deformation of the tested material. Research has shown that it is quite possible to obtain ceramics based on TiB2-FeSi by the SPS method without the use of a vacuum, gas, etc. environment and in a fairly short period of time in comparison with the known methods of obtaining ceramics based on TiB2. Also, in contrast to hot pressing in a vacuum, a rather small mechanical load is used for pressing. Under such insignificant conditions of electro-mechanical load and a short SPS time, sufficient mechanical characteristics of ceramics were obtained, which allow its use as a cutting tool or a sliding body in friction pairs.

References


1. A. I. Kharlamov, M. E. Bondarenko, A. N. Rafal. Kinetics of interaction of transition metals with silicon nitride.

// Silicides and their use in technology: collection of articles. scientific works – K.: IPM AN Ukrainian SSR, 1990.

– P. 35-40. 2. Makarenko G.N., Timofeeva І.І., KrushinskayaL.А., MatseraV.E., ZyatkevichD.P. ”Preparation of composite powders based on titanium Boride and silicides of transition metals” Abstracts of 6-th International Samsonov conference “Materials science of refractory compounds”. Kyiv, Ukraine. May 22-24, 2018. p. 63. Access mode: ”http://www.materials.kiev.ua/conferences/MTC2018/Eng_Samson.pdf”


3. A. S. Petukhov; I. V. Khobta; A. V. Ragulya; A. V. Derevyanko; A. I. Raichenko; L. P. Isaeva; A. M. Koval’chenko. Reactive electric-discharge sintering of TiN-TiB2. - Powder Metallurgy and Metal Ceramics. – 2007, v.46, №11-12; P.525-532. https://doi.org/10.1007/s11106-007-0081-x



Thermodynamic approach to studying of processes of contact interaction between W – C filler and iron-based binder of composite materials during infiltration


Yuliya Syrovatko1,2, Eduard Shtapenko1

yu.syrovatko@gmail.com

1Ukrainian State University of Science and Technologies, Ukraine

2Dnipropetrovsk Branch of the State Institution “Soil Protection Institute of Ukraine”

Higher performance characteristics of the composite materials with iron-based binders can be achieved by reducing the fragility of contact interaction zones through changing of the structure of granules of the W – C filler alloy. Previous experimental work showed the lower rate of dissolution of phases of the microcrystalline W – C filler alloy in the binder, compared to the crystalline W – C filler alloy [1]. The entropy of microcrystalline and crys- talline structures of W – C alloys was determined by scanning of their digital photo-images with the use of TLC_Manager software. Further, statistical distribution of the probability density for the optical absorption coefficients was formed. Based on the fact, that log- arithmic representation of the normal distribution functions is of the form of quadratic functions, we calculated the statistical distribution parameters [2]. It allowed calculating the entropy of structures at 300 K. Obtained values were 82 and 76 J/(mol∙К) for the crys- talline and microcrystalline structures, accordingly. On the other hand, using the Debye model representations, we expressed the Helmholtz free energy and entropy as the func- tions of temperature and Debye temperature. From these expressions, knowing the values of entropy of the structures at 300 K, we found the Debye temperatures of structures, as well as the values of entropy, free energy and Gibbs energy of these W – C alloys at the temperature of infiltration of composite materials (1523 К). W – C filler and iron binder of the composite materials during infiltration were considered as two systems being in dif- fusion and thermal contact. The larger the difference in the chemical potentials of these systems, the more intense are the processes of diffusion and dissolution occurring at the interface of the systems [3]. It is found that the difference in chemical potentials of the microcrystalline filler alloy and the binder is less than that of the crystalline filler alloy.

Acknowledgments


This work was performed within the research “Development of plasma technologies for strengthening coatings used in extreme conditions”, No. of the State registration 0123U104531

References


1. O. V. Sukhova, Yu. V. Syrovatko, Adhesion of Melts and Brazing of Materials, 2012. V.45. P. 86 - 93. 2. E. V. Sukhovaya, Yu. V. Syrovatko, Metallofiz. Noveishie Tekhnol., 2019. V. 41, No. 9. P. 1171 - 1185. 3. Ch. Kittel, Thermal Physics (New York: John Wiley and Sons Inc., 1969).



Effect of TiC additive on elasticity and electrical resistivity of reaction sintered nanosized SiC matrix composites


Oleksandr Vdovychenko1, Mykola Gadzyra1, Anatoliy Kolesnykov1, Neonila Tkachuk1, Ihor Hnylytsia2

vdovyche@gmail.com

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2Ivano-Frankivsk National Technical University of Oil and Gas, Ukraine

Silicon carbide (SiC) is one of the most important engineering ceramic because of its good thermal conductivity, oxidation and corrosion resistance, and mechanical properties. The need in reliable electronic devices for operation under shock cyclic loads and shear stresses requires the study of a combination of electrical and mechanical properties of SiC-based ceramics. In contrast to high-cost hot sintering, pressureless sintering and liquid-state sin- tering are used to obtain relatively low cost SiC-based products of complicated shape with excellent mechanical properties. [1] SiC-matrix composite obtained by reaction sintering of nanosized silicon carbide powders with various amounts of nanosized titanium carbide (from 1 to 8 wt% in increments of 1%) introduced into the composition of the initial charge were studied. The process of infiltration of porous blanks was also carried out in an in- duction furnace at a temperature of 2273K. Elastic characteristics were calculated based on the results of determining the density of samples using Archimedes method and the velocities of longitudinal and transverse acoustic waves using the pulse-echo and resonant techniques. It was established that with an increase in the content of titanium carbide, the specific electrical resistivity of the composites SiC-TiC decreases from 49.4x10-5 Ohmm to 5.8x10-5 Ohmm, instead, the elastic characteristics change non-monotonically. Young modulus E and shear modulus G tend to increase in the range of 1 to 4% TiC, followed by a decrease. The values of the Young modulus E vary in the range of 256 to 348 GPa, and the shear modulus G - in the range of 104 GPa to 151 GPa. Instead, the values of Poisson ratio change with the opposite trend in the range from 0.15 to 0.28 and have a minimum for the material SiC-5% TiC. Possible reasons for the specified changes in electrical resistivity and elastic characteristics are discussed.

References


[1] Y.-W. Kim, Y.-H. Kim and K. J. Kim, Electrical properties of liquid-phase sintered silicon carbide ceramics: a review, Crit. Rev. Solid States Mater. Sci., 2020, V.45, P.66-84.



3D printing of auxetic structures by the FDM method


Vladislav Moroz, Vladislav Naumenko, Ostap Zgalat-Lozynskyy

moroz.vladislav@lll.kpi.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


With the development of 3D printing techniques, metamaterials, such as auxetic structures, became a new area of research. 3D printing of auxetic structures from various materials has attracted considerable interest in the scientific community due to their unique proper- ties, such as negative Poisson’s ratio. Using various composite materials, it is possible to achieve high strength, lumpiness, biocompatibility and other properties that make them attractive for various technological and engineering applications. In many studies, em- phasis is placed on the development of new methods of manufacturing auxetic materials, as well as on understanding their microstructure and deformation mechanisms. For ex- ample, the possibility of using various manufacturing techniques, including 3D printing, to create materials with desired auxetic properties is being explored. Some research is aimed at developing materials with unique combinations of properties, such as combined auxetic and piezoelectric behavior, which may have applications in sensor and actuator systems, as well as in aerospace and biomedical and medical fields. At current investiga- tion the auxetics were printed on a Creality Ender-5 printer using 1.75 mm diameter PLA filaments reinforced with ceramic particles and fibers. 3D models are designed and edited in Blender, Autodesk Netfabb programs, prepared for printing in Simplify3D. The use of different materials and their combinations in 3D printing allows you to create materials with different properties in one part. This opens up new possibilities for creating auxetic materials with unique mechanical and physical characteristics.

Acknowledgments


The work the was done as part of the joint UKRAINIAN-GERMAN R&D project ”Machine Learning Enhanced Additive Manufacturing”

References


1. Zgalat-Lozynskyy, O.B. Materials and Techniques for 3D Printing in Ukraine (Overview). Powder Metall Met Ceram 61, 398–413 (2022). https://doi.org/10.1007/s11106-023-00327-y 2. Oleksandra Tolochyna, Nataliya Zgalat-Lozynska, Yury Podrezov, Dmytro Verbylo, Oleksandr Tolochyn, Ostap Zgalat-Lozynskyy, The role of flexi- ble polymer composite materials properties in energy absorption of three-dimensional auxetic lattice structures, Materials Today Communications, Volume 37, 2023, 107370, https://doi.org/10.1016/j.mtcomm.2023.107370



Phase diagram of the Tb3Sc2Al3O12–TbScO3 system


Serhii Lakyza, Monica Tomchzyk, Jaroslaw Korol, Dorota-Anna Pawlak

sergij_lakiza@ukr.net


ENSEMBLE3, Centre of Excellence, Poland


Eutectics present the unusual characteristic of being at the same time a monolith and a multiphase material. They have the potential for optical, electronic and magnetic applica- tions. Their properties can be divided into two categories: additive properties and product properties. The additive properties depend on volume fraction and spatial distribution of the phases, while the product properties depend on interaction between the phases and depend on periodicity and the size of the phases. The Tb3Sc2Al3O12–TbScO3 (TSAG-TSP) eutectic is interesting optically active material in which both radiative and measured life- times of 5D4 manifold of Tb3+ ions are longer than in bulk TSAG and TSP crystals. These eutectic materials have a high potential for photonic applications. The authors [1] grew TSAG single crystals by micro-pulling down method and found the formation of areas of binary eutectic TSAG-TSP at the edge of TSAG single crystal. The reason was the com- position deviation during the growing process. So the quasibinary section TSAG-TSP was stablished in the system Tb2O3–Sc2O3–Al2O3. Then the directional solidification of TSAG- TSP eutectic was performed [2], but the coordinates of this eutectic was not established and bulk material with primary TbScO3 crystals was obtained. At the present time we have no information about phase diagram of this system, so the construction of it is the purpose of given investigation. The bulk directionally solidified µPD crystal was analyzed by DTA, SEM+EDS methods and coordinates of TSAG-TSP eutectic was established (1805

°C, 25 mol.% TbScO3). TbScO3-based solubility area does not exceed ~1 mol.%. TSAG- based solubility was not determined. Phase diagram of this system is shown in Fig. 1, microstructures – in Fig. 2.

References


1. D. A. Pawlak, G. Lerondel, I. Dmytruk, Y. Kagamitani, S. Durbin, P. Royer, T. Fukuda, Second order self-organized pattern of terbium–scandium–aluminum garnet and terbium–scandium perovskite eutectic,

J. Appl. Phys., 91 [12] 9731-9736 (2002). 2. K. Kolodziejak, S. Turchinski, R. Diduszko, L. Klimek, D. A. Pawlak, Tb3Sc2Al3O12-TbScO3 eutectic self-organized microstructure for metamaterials and photonic crystals application, Opto-Electronics Review, 4 [3] 205-211 (2006).



EPR study of spectral characteristics of REE oxides.


Mykola Bataiev, Natalia Barchevska, Olena Lavrynenko, Yurii Bataiev

bataiev.2@gmail.com


IPMS of I.M. Frantsevich of NASU, Ukraine


The intensities of the EPR line for Er2O3 REE samples correspond to the Lorentz line theoretical model [1]. The dependence of the intensity of the lines on the corresponding the gain value has a linear model of the parameters. Dependence plane of the EPR line corresponding to the number of spin domains of the sample, as well shows a linear model of the coefficient value. EPR spectral lines located at 3560G, 1665G, and also at 3050G on the scale of the electromagnetic resonance field refer to the main ion Er3+ rare earth oxide (REE) oxide Er2O3 [2] EPR lines indicate the presence of ions in the corresponding electronic form and refer to the spin of ions and REE oxides. The value of the factors is 1.7554 for the oxide system of Er2O3-CeO2 oxide [1, 2] testifies to the presence of Er3+ ion in the system of the cubic form of Er2O3 oxide and corresponding phase formation of rhombic Er2O3 oxide after heat treatment 1100ºС-1500ºС. The g-factor value of 1.7554 in the EPR spectrum implies the presence of the main one Er3+ ion with an additional shift, which corresponds to the appearance and new formation of an additional one of the phase part of the Er2O3 oxide after high-temperature treatment of the material oxide 1100ºС- 1500ºС. The g-factor value of 2.049 is responsible for the proper transition of the main Er 3+ ion with the electronic structure 4f 11 5s 2 5p 6 of the oxide Er2O3 . Spin configuration state for Er3+ oxide Er2O3 is defined in the format 4 I 15/2 . The g-factor value is 0.958 is responsible for the Er2+ -based ion transition with an additional shift that implies the presence of Er ions in different formats in different concentrations in oxides systems based on Er2O3 . The configuration of the ion Er2+ electronic state is determined 4f 12 5s 2 5p 6 and the configuration of the spin state for the Er2+ ion is defined by 3H6 .

Acknowledgments


The authors are grateful to O. A. Kornienko and Frantsevich Institute for Problems of Material Science NASU.


References


[1] Bataiev М.М., Bataiev Yu.M., Lavrynenko O.M., Kornienko O.A., Nanotechnologii, 18 (2), 311-320, (2020). [2]

O.M. Lavrynenko, O.I Bykov, Yu.M. Bataiev, M.M. Bataiev, O.A. Kornienko, Bulletin of ONU, Chemistry, 25, 3 (75) 2020.



Residual thermal stresses in cemented carbide with mesostructure


Nataliya Litoshenko

lytnat@ukr.net


V.M. Bakul Institute for Superhard Materials, Ukraine


The development of composite materials with mesostructures is a relevant task today [1, 2]. One of the effective methods to increase the workability of products made of WC–Co, WC–Ni, TiC–WC–Co hard alloys is to form a mesostructure in them, which will make it possible to improve physical and mechanical properties and simultaneously achieve high wear resistance and fracture toughness [3], as well as double the value of the strength limit and four times the fracture deformation during compression tests. In hard alloys, the meso-structure consists of mesoelements - an ensemble of carbide particles cemented by a binding metal and a metal phase. The properties of such compositions depend on the composition, structure and state of the mesoelements and the matrix. Carbide products with a mesostructure are promising in the mining industry and mechanical engineering. In particular, using them in hard alloy elements of friction pairs and sealing units, it is possible to achieve the most optimal ratio of wear resistance and fracture toughness. The level of residual thermal stresses in granules and interlayers of mesostructural hard alloys (WC–Со)gran–Со, (WC–Ni)gran–Ni, (TiC–Со)gran–Со, (TiC–Ni)gran– Ni , arising during its cooling from the sintering temperature to room temperature was established by analytical methods. The dependence of local stresses on the content of the binder phase in the granule and hard alloy was studied for a layer thickness equal to 10% of the radius of the granule. With an increase in its content from 15 to 30 wt%, compressive stresses in a WC carbide with a binder content of 3…25 vol% increase from –25 to –366 MPa, and the tensile stresses in the Co layer change from 1134 to 687 MPa. The tensile stress values in the matrix layers are lower than in standard hard alloys of similar brands, in particular for (WC–Ni)gran–Ni – by 69%, and for (WC–Со)gran–Со – by 30%.

References


1. Lisovsky A. F. Theory and Practice of Mesostructure Formation in Composite Materials. A Review // Journal of Superhard Materials. – 2020. – Vol. 42, № 3. – P. 129–144. 2. Technology of formation of mesostructures in sintered WC–Co and WC–Ni solid alloys / O. O. Matviichuk, I. V. Andreiev, I. O. Hnatenko, O. V. Ievdokymova, S. А. Davydenko, and M. О. Tsysar // Materials Science. – 2022. – 58, № 29. – P. 175–179. 3. Mechanical properties of a hybrid cemented carbide composite / X. Deng, D. R. Patter-son, K. K. Chavla, M. C. Koopman, Z. Fong, G. Lockwood, and A. Griffo // Int J. Refr. Met. Hard. Mater. – 2001. – 19. – P. 547–552.



Preparation of composite powders based on titanium-chromium diboride by the method of plasma spheroidization for gas-thermal spraying and surfacing of protective coatings.


Volodymyr Konoval1, Mykola Skulskyi2, Mykola Liutik2, Oleksiy Bondarenko1, Konstyantyn Gal’tsov1, Arutiun Avetisian2, Olena Poliarus1, Oleksandr Umanskyi1

v.konoval@ipms.kyiv.ua

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2Klakona Systems, Ukraine

To obtain the coatings with various special properties, such as heat- and wear resistance under friction conditions at high speeds, loads and the absence of lubrication, refractory compounds and composite materials based on them in the form of powders are used. The properties of composite powders, as well as coatings obtained from them, depend on the method of their production [1]. The goal of the work is to obtain composite metal-ceramic powders with good technological and mechanical properties for gas-thermal spraying and surfacing of coatings. Powder mixtures (Ti,Cr)B2 –NiAlCr, (Ti,Cr)B2 –AlN(SiC)–NiAlCr were obtained by mixing in a planetary mill. The particle size was ~3÷12 µm. Subse- quently, the powder mixtures were conglomerated using organic binding materials, after which the particle size was ~40÷90 µm. These powders were passed through a plasma jet, causing them to sinter and become spherical. For powders, fluidity, bulk density, mi- crohardness, microstructure, phase and chemical composition were studied. Detonation method coatings were sprayed from the powders. Spheroidized powders have good tech- nological properties: fluidity τ=33÷74 sec., bulk density ɣ=1,76÷3,05 g/cm 3 . A sin- gle particle of powder has a spherical shape with high strength and microhardness Н µ

=870÷3300 MPa which are comparable to the values of sintered compact materials. Pow- der particles have a heterophase microstructure with a uniform distribution of metallic and refractory components. (Ti,Cr)B2 –NiAlCr powders have the best technological and mechanical properties. Powders with AlN and SiC additives have a more branched particle surface. With increasing AlN and SiC content the surface of the particles becomes rougher and the fluidity of the powders worsens. Detonation coatings from the resulting powders have a heterophase microstructure with a uniform distribution of structural components. The adhesion strength of the coatings to the base is σ=91÷115 MPa and the density is 98÷99%.

References


1. Mitin B.S. Poroshkova metalurgiya i napylenie pokrytiya. M.: Metalurgiya, 1987. 791 s.



Theoretical evaluation of mechanical properties of inverse opal structure


Pavlo Korobko1, Andrii Kuzmov1,2

pavlokorobko@gmail.com

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

The study focuses on the theoretical evaluation of the mechanical properties of porous materials with an inverse opal structure which serves as the object of the study. The sub- ject of the study is the process of transition from elastic to irreversible deformation. The purpose of this study is to apply the finite element method to model this process to reveal the relationship between the structural characteristics of materials, such as porosity and coating thickness, and their mechanical properties [1]. The yield surface was constructed by computational modelling on a representative cell with a number of points in the (p,τ) plane for several cases of inverse opal structure - for a highly porous uncoated structure and structures with an additional layer [2]. As a result of the study, yield surfaces of the structure under investigation were constructed for several porosity values, from 0.56 to

0.9. In the result of the work, the approximation of the numerical appearance of the yield surface by a Deshpande-Fleck crushable foam model available in finite element modelling packages was made [3]. The conclusions of the study show that the effective plastic proper- ties of materials with an inverse opal structure significantly depend on their porosity level and the presence of additional coatings. The obtained yield curve for a porosity of 0.9 is close to the associated plastic flow law, which allows us to assess the material’s behaviour under loading based on the results of the uniaxial stress state. However, for a structure with medium porosity and an additional coating layer, the surface becomes significantly unassociated, with a discrepancy of almost 30%. The application of the Deshpande-Fleck model for crushable foam in the approximation of the obtained numerical data from the study demonstrated the relevance of the model in describing the plastic behaviour of this structure only at high porosity values.

Acknowledgments


This research was part of P. Korobko’s PhD study which is carried out under the state order.


References


1. Bakhvalov N.S., Panassenko G.P. Upscaling: Averaging Processes in Periodic Media. Kluwer Academic Pub- lishers, 1989 2. Christensen R.M. Mechanics of Composite Materials. Wiley-Interscience, New York, 1979. 348

  1. 3. Pikul J.H., Özerinç S., Liu B., Zhang R., Braun P.V., Deshpande V.S., King W. P. High strength metallic wood from nanostructured nickel inverse opal materials. Scientific Reports. 2019. No. 719



    Method for modifying cast iron with briquetted powder modifiers during casting by gasification models


    Gennadii Bagliuk, Natalia Uskova, Anatolii Trotsan, Aleftina Mamonova, Galina Molchanovska

    don1945@ukr.net


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    At present, the most promising direction in the development of technology for the pro- duction of low-strength cast iron with spheroidal graphite is inoculation in a casting mold [1]. In this work, the parameters for obtaining castings from ductile iron during their processing with briquetted powder modifiers were developed. The structural and phase mechanism of the interaction of alloying elements (magnesium, silicon, manganese, rare earth metals, TiN2-TiC) on the structure and properties of cast iron intended for the man- ufacture of parts by casting on gasified models. Modifying briquettes containing 10%Mg, 50% ferrosilicon niobium, 2%CaF, 38%Fe with the addition of FS30REM 10% in one com- position from the addition of 1% TiN2-TiC in the other were placed in a casting molds in an amount of 2% by weight of the metal being processed. Microstructural and X-ray phase studies of the alloy indicate their multiphase composition. The X-ray spectrum of unmod- ified cast iron is represented by the hardening carbide phases SiC, Fe3C, C and the α-Fe phase. The microstructure of original cast iron is pearlite and lamellar graphite. The phase composition of cast iron of modified composition of rare-earth metals is represented by the main phase α-Fe, carbides Fe3C, SiC. A characteristic feature of the alloy is the formation of the FeSiC phase. When 1% TiN2 –TiC is added to briquettes, along with the phases C, SiC, Fe3C, α-Fe, complex titanium carbides based on TiC are formed - C0.7N0.3Ti and C0.3N0.7Ti. The parameters of the fine structure of cast iron with a modified composition of REM and TiN2 –TiC testify to the high dispersion of the coherent scattering region equal to 26.7 nm. When studying the features of the morphology of the structure of alloys on a microanalyzer of modified cast iron of all compositions in thin-lamellar pearlite, partial spheroidization of the carbide phase occurs. Processing cast iron using this technology ensures good strength properties of castings.

    References


    1. G. Baglyuk, V.Kurovskiy. The features of structure and properties of high-strength cast irons, treated with bri- queted powder modifiers 9th international congress ”Machines, technolоgies, materials‘2012” 19 – 21.09.2012, Varna, Bulgaria, P.86-89.



Structural design of superhard PCBN composites of BL group


Mykola Bezhenar, Yaroslav Romanenko, Andriy Patsyk

bezhenar@ukr.net


  1. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


    Superhard PCBN composites of the BL group are tool materials with 45-75% cBN content and cBN grain sizes up to 3 microns. Typically, the bond consists of refractory titanium compounds like TiN, TiC, or TiCN. These composites are primarily for high-speed finishing and semi-finishing blade processing of heat-resistant chromium-nickel alloys and steels. The cutting tool experiences low loads with predominant tribochemical wear [1]. PCBN composites of the BL group are produced by sintering at high pressures (3-8 GPa) and tem- peratures (1600-2300 K) in various types of high-pressure devices (HPD). The structure’s requirements stem from the need to protect cBN grains and ensure effective cutting. Two possible structures include individual cBN grains surrounded by a bond or a double frame structure. Effective cBN grain performance relies on firm bonding aided by surface de- velopment and coherence within the composite. For finishing cutting operations, surface cleanliness depends on cBN grain size, often requiring sizes under 3 μm. Key requirements for cBN powders and refractory components include: a) cBN grain size not exceeding 3 μm, occasionally up to 7 μm for semi-finishing turning; b) refractory component grain sizes two to three times smaller; c) absence of oxygen in refractory powders to prevent phase conversion and weakening of the composite; d) preferably developed surface of starting powders; e) desirable non-stoichiometry of refractory components to increase reactivity during sintering and enhance interfacial coupling. The obtained polycrystals in the sys- tems (cBN – a refractory compound from the TiC, TiN, TiCN, TiB2, ZrN – aluminum series) had a homogeneous structure at the level of cBN grain size with acceptable hardness (25- 28 GPa), crack resistance (7-9 MPa·m1/ 2) and thermal conductivity (50-80 W/(m·K)).

    References


    1. Bezhenar, M.P.; Bozhko, S.A.; Garbuz, T.O.; Krishtova, E.V.; Belyavina, N.N. Sintering at high pressures of cBN powders with additives of refractory compounds (in Russian), High Pressure Physics and Technique, 2007, Vol. 17, No. 2, P.86-95.



Cobalt migration into the working layer of PCBN composite during sintering of cBN powders on a carbide substrate


Mykola Bezhenar, Yaroslav Romanenko, Andriy Patsyk, Oleksandr Sokolov

bezhenar@ukr.net


  1. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


    Superhard PCBN composites are typically produced by sintering cubic boron nitride (cBN) powders onto a substrate of WC-Co carbide under high pressure (3-8 GPa) and tempera- ture (1600-2300 K) conditions. A crucial aspect of these bilayer composites is the strong bonding at the carbide-cBN interface [1]. The initial materials were hard alloy VK15 and cBN powder (5-7 microns), sintering occurred in a cubic high-pressure apparatus at 1600 K and 4.5 GPa for 20 minutes. The resulting two-layer wafers had a carbide substrate thickness of 2.2 μm and a cBN working layer of 1 μm. Four distinct regions were observed near the carbide-cBN contact zone: Region 1: Carbide region over 20 μm from the contact boundary, with WC grains (2-3 μm) and cobalt veins. Region 2: A light near-contact zone, roughly 20 μm wide, with minimal cobalt. Region 3: A 30 μm wide zone with black cBN grains (5-7 μm) and decreasing cobalt content away from the interface. Region 4: Poly- crystal cBN with minimal cobalt, over 50 microns from the interface. Micro-X-ray spectral analysis corroborated: In region 1 the amount of cobalt at the level of 10 - 12 %, boron and nitrogen are absent. In region 2 the amount of cobalt decreases sharply, almost to zero at distances from 10 μm and up to the interface, boron and nitrogen appear at distances up to 5 μm from the interface, the maximum amount is 12 % wt. at a distance of 1 μm from the interface. In region 3 10 % Co at the interface, 5 % at 10 µm distance, 3 % at 30 µm distance from the interface. Tungsten was also detected (3 % at the interface, 2 % at 10 µm distance and 0.5 % at 50 µm distance). Region 4 - at a distance of 500 µm from the interface, mainly boron and nitrogen (cBN), traces of Co and W (up to 0.3 %, possibly deposited on the surface during preparation of the slurry. Conclusions: Cobalt seeps into the cBN layer up to 50 μm. Cobalt depletion can lead to embrittlement of the material near the interface. Tungsten also penetrates the cBN layer.

    References


    1. Shulzhenko A.A., Bezhenar M.P., Tkach S.V., Tkach, V. N., and Bozhko, S. A. Structure formation and hardness of cubic boron nitride composites during reaction sintering on carbide substrate. Supertv.materials. 2005. №3. P. 3-13.



Phase composition and properties of cubic boron nitride polycrystals cBN – Al systems depending on the conditions of obtaining.


Mykola Bezhenar, Yaroslav Romanenko, Andriy Patsyk

bezhenar@ukr.net


  1. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


    Polycrystalline superhard materials (PCBN) based on cubic boron nitride (cBN) find appli- cation in roughing, semi-finishing, and finishing grinding of iron-carbon alloys up to 63 HRC, in-cluding those alloyed with chromium, manganese, and nickel. These materials are produced by sintering cBN powders with various additives, commonly aluminum [1, 2]. Let us consider three variants of this interaction, which are realised in the production of BN-class PCBN composites known by the trademark “kiborite” at the V. Bakul Institute for Su-perhard Materials of the National Academy of Sciences of Ukraine: Option 1: Using a high-pressure steel anvil with a recess at 4-4.5 GPa and 1400-1500 °C, chemical interaction between Al and BN results in AlN and AlB2 formation. This scheme yields composites with cBN, AlN, and AlB2, offering high hardness (27-29 GPa) and crack resistance (10- 13 MPa·m1/2). However, low heat resistance due to AlB2 decomposition above 1000 °C is a drawback. Option 2: Employing toroidal high-pressure carbide devices at 6-8 GPa and 1700-2000 oC, Al and BN interact to form AlN and AlB12. The resulting composites feature very high hardness (34-40 GPa), heat resistance (1200 oC), and acceptable crack resistance (8-10 MPa·m1/2). Yet, high pressure and temperature requirements and the use of scarce hard alloys are drawbacks. Option 3: Utilizing a high-pressure steel anvil with a recess at 3-4.2 GPa and 1400-1500 oC, Al and BN react to form AlN(B). These composites consist of cBN and a solid solution of boron in aluminum nitride’s lattice. Offering high heat resistance (1200 oC), crack resistance (11-13.5 MPa·m1/2), and acceptable hardness (25-28 GPa), they also exhibit high damping characteristics. However, the drawback lies in the formation of hexagonal boron nitride when sintering cBN pow-ders with grain sizes less than 3 µm due to decreased pressure and impurities.

    References


    1. Novikov N.V., Shulzhenko A.A., Bezhenar N.P., Bozhko S.A., Borimsky A.I., Nagorny P.A. Kiborite: preparation, structure, properties, application // Superhard Materials.- 2001. №2.- С. 40 - 51. 2. Bezhenar, N.P.; Bozhko, S.A.; Belyavina, N.N.; Markiv, V.Ya.; Nagorny, P.A. Phase composition of polycrystals obtained by reaction sintering of cubic boron nitride with aluminium // Superhard Materials. - 2002. - №1. - С.37-48.



Electromagnetic properties of AlN-based composite materials with C and Mo additives


Tetiana Serbeniuk1, Tetiana Prikhna1, Oleksii Kalenyuk2,3, Sergii Futimsky2,3, Volodymyr Sverdun1, Andrii Shapovalov2,3, Miroslav Karpets1,4,5

serbenuk@ukr.net

1Bakul Institute for Superhard Materials, NASU, Ukraine

2G. V. Kurdyumov Institute for Metal Physics, NASU, Ukraine

3Kyiv Academic University, Ukraine

4National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

5Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

The new composite materials with a high level of dielectric constant were created on the AlN-based. These materials were obtained by the hot pressing method at temperatures of 1800-1820 °C and a pressure of 15 MPa from powders mixtures AlN-Y₂O₃-5%C(soot), AlN-Y₂O₃-3%C(diamond powder - DP), AlN-Y₂O₃-5%C(DP)-5%Mo. The structural and phase composition of the composites was investigated by X-ray phase analysis using the Rietveld method and using a Zeiss Evoma15 SEM. The measurements of the complex dielectric con- stant in the frequency range of 12.4-18 GHz were carried out by the waveguide method using the Keysight P9375A vector microwave circuit analyzer. The main AlN phase and the presence of new phases: С(graphite), Al₃(O,N)₄, and Al in the materials structures were revealed by the X-ray phase method. The graphitization process of DP is characteristic for these compositions and at free sintering [1]. In addition, the formation of Mo₂C is observed in the system AlN-Y₂O₃-C(DP)-Mo. Also, thanks to X-ray studies and SEM with analysis of the quantitative elemental composition in the main phases by the EDS method, was estab- lished the presence of a low concentration of O in the AlN lattice and was revealed the location of conductive phases (C, Mo₂C) in the structure of materials. The results of mea- surements of electrodynamic characteristics showed that the developed new composite ma- terials with graphite phase inclusions have constant dielectric characteristics in the entire frequency range and are at the level of ɛr = 12.38-33.03 and tgδ=0.06-0.51. Composites with soot had the highest values of dielectric constant (33) and losses (0.51). Preservation of high dielectric characteristics of composites, and at the same time increasing the level of dielectric permeability, is achieved due to the features of structure formation, in partic- ular, arrangement of conductive phases grains (C, Mo₂C) in the structure of composites and minimization of contacts between them.

References


1. Serbeniuk T.B., Prikhna T. O., Sverdun V. B., Oliynyk V. V., Grygoruk V.I., Zagorodnii V. V., Karpets M. V., Ponomaryov S. S., Marchenko A. A., Polikarpova L. O. Effect of varying graphite concentration on electrodynamic properties of AlN-based composite materials. Journal of Superhard Materials. 2023. Vol. 45, No. 6. P. 424- 433.



Modeling of the impact process of the bullet core made of hard alloy with a high entropy FeNiCrMoW binder into an obstacle


Vitalii Mykhailichenko, Anatolii Minitskyi, Oleh Stepanov, Olexandra Yurkova, Serhii Nakonechnyi

wertyxa2002@ukr.net


National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


In modern conditions, increasing the armor-piercing characteristics of small arms ammu- nition is an important task. One of the promising ways to solve this problem is to improve the composition of the composite materials from which bullets cores are made [1]. In order to reduce research costs and optimize the design of new products, simulation of product behavior in real conditions is widely used. During the study, a composite powder material of the tungsten carbide and high-entropy equimolar NiFeCrWMo alloy was obtained using the methods of mechanical alloying and vacuum sintering in the ratio of 90 wt. % and 10 wt. % respectively. To obtain a model of the behavior of the material under conditions of intense dynamic loads, a combination of the Johnson-Cook model, which describes the pro- cesses of deformation and destruction of the material, the equation of state of stress waves, which characterizes the speed of particles and the speed of stress waves during high-speed deformation, the shear modulus and Poisson’s ratio was used. A material model was cre- ated using experimentally determined data, which can be used in other similar calculation works for modeling processes of various nature. The process of hitting an armor-piercing bullet into an armor plate was simulated using the Ansys 2020 R2 student edition software using the finite element method. For this purpose, models of the armor-piercing bullet and plates of the required thickness were created and the values of the material parameters were assigned to them. As a result of modeling, it was established that the core of the bullet made of tungsten carbide and high-entropy binder is almost not inferior in terms of strength characteristics to the core of the bullet made of tungsten carbide and cobalt and has similar parameters of penetration ability.

References


1. Yurkova, O.A., Minitskyi, A.V., Nakonechnyi, S.O. et al. Investigation of the Influence of High Speed Sintering Regimes on the Structure and Properties of WC Based Carbide Composites with High Entropy Bonding, Journal of Superhard Materials, 2024, V. 46, P. 32–39.



In-situ formation of borides and their effect on structure and mechanical properties of AlNiCrTiB high-entropy alloy prepared by electron-beam sintering


Serhii Nakonechnyi, Alexandra Yurkova, Petro Loboda

s.nakonechniy@kpi.ua


National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


Metal-ceramic composites based on high-entropy alloys have an excellent combination of various properties of metal and ceramic materials [1]. At the same time, one of the most promising ways to obtain such composites is the introduction of non-metallic elements, such as boron [2, 3]. The in-situ formation of ceramic particles/fibers can significantly im- prove different characteristics of the resulting composite. In this study, a mechanically alloyed, for 10 h in petrol environment, equiatomic powder mixture of the Al-Ni-Cr-Ti-B system was sintered by electron beam method using different currents (4, 6 and 8 mA) applied to the cathode of electron beam gun. At the current strength of 4 mA, an alloy ex- hibits the transformation of the BCC phase resulted from MA into the FCC phase, as well as the formation of small inclusions of boride phases based on Cr and Ti. An increased average microhardness of 7.5 GPa is achieved due to interstitial strengthening by dissolu- tion of boron element in the voids of solid-solution lattice and alloy quenching. Increasing the current strength to 6 mA leads to the formation of a significant amount of titanium diboride inclusions. However, a higher content of the BCC phase is transformed into a soft FCC phase, reducing the average microhardness to 3.0 GPa. At a current of 8 mA, the phase composition of the alloy does not change, but three heating zones are formed in the microstructure. In the zone of electron beam contact, a FCC matrix with inclusions of chromium monoboride fibers is formed, and the average microhardness here is 7.4 GPa. In- side the sample, at a distance of 2-3 mm, the microstructure consists of a same FCC matrix and titanium diboride inclusions, and the average microhardness reaches 11.8 GPa. After that, the microstructure and microhardness of the alloy are like those obtained at 6 mA. The results reflect the prospects and the necessity of further research on the formation of the structure and properties of such materials.

Acknowledgments


This study was funded under the project of the Ministry of Education and Science of Ukraine, state registration number 0124U000913.

References


[1] M.A. Mehmood, K. Shehzad, M. Mujahid, T.B. Yaqub, A. Godfrey, F. Fernandes, F.Z. Muhammad, K. Yaqoob, Ceramic-reinforced HEA matrix composites exhibiting an excellent combination of mechanical properties, Sci. Rep., 2022. V. 12. Article Number 21486. [2] B. Xin, A. Zhang, J. Han, J. Zhang, J. Meng, Enhancing me- chanical properties of the boron doped Al0.2Co1.5CrFeNi1.5Ti0.5 high entropy alloy via tuning composition and microstructure, J. Alloys Compd., 2022. V. 896. Article Number 162852. [3] J. Chen, Y. Long, H.-T. Lin, F. Zhang, Friction and wear behaviors of boron-containing high entropy alloy/diamond composites, Diam. Relat. Mater., 2024. V. 144. Article Number 110998.



Structure and properties of the Fe3Al-TiC composites obtained by hot forging


Oleksandr Tolochyn, Stepan Kyryliuk, Gennadii Bagliuk, Oleksandra Tolochyna

o.tolochyn@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Modern developments of more productive power systems are based on the principles of energy and resource saving and are associated with increasing their efficiency and in- creasing temperature and force loads. For such operating conditions, intermetallic matrix composites strengthened with carbides, borides or oxides are being considered, which will combine the heat- and wear-resistance of ceramics with the engineering properties of in- termetallic compounds. Iron aluminides is a good matrix material in such composites due to their excellent resistance to oxidation and sulfidation at elevated temperature, as well as good fatigue and creep strength [1]. The intermetallic composites reinforced with car- bide particles were produced by powder metallurgy. The mixtures obtained by planetary grinding of powders were formed into samples and heated and compacted by hot forging at 1220°C. The consolidated samples were tested for physical and mechanical properties. Compression tests were carried out at temperatures of 20 and 700°C. The formation of the phase composition and structure of the composite occurs at each technological stage of the material production. While the carbide phase TiC (10-30 vol.%) is introduced as a whole compound and as a result of intensive milling it can be ground to a particle size of 0.7-2 µm, the oxide hardening phase FexAlyOz with a particle size of 0.08-0.2 µm is formed during the milling of powders. The formation of the matrix phase, occurs as a result of re- action synthesis during heating. A feature of the deformation structure is the formation of lamellar particles of iron aluminide 5 μm. Fine particles of the strengthening phase are located inside and mainly at the grain boundaries. With an increase in the amount of carbide phase, a decrease in the bending strength is observed from 1700/1560/1330 MPa for composition 10/20/30 vol.% TiC. Compression tests showed high yield strength — 800-1100 MPa at room temperature and 400-440 MPa at 700°C.

Acknowledgments


The work was supported by the National Research Foundation of Ukraine (project no. 2021.01/0278)


References


1. Mitra, R. Intermetallic matrix composites: Properties and Applications. Woodhead Publishing Series in Com- posites Science and Engineering. 2017. 486 p.



Thermal stability of composite materials based on boron oxide modified basalt fibers


Stanislav Ivanitskii, Yurii Chuvashov

svan7775@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Composite materials (CM) based on fibers containing B2O3 are used for neutron radiation shielding in nuclear reactors. Thermal stability of CM is related to the ability to maintain high strength of reinforcing fibers under thermal loads. The main reason for the decrease in strength is crystallization. This is due to the development of microcrystalline nuclei that formed in the fibers at the stage of drawing in the crystallization zone. The aim of this work is to analyze the influence of the rheological properties of the melt containing B2O3 on the conditions of fiber drawing, which affect the appearance of the microcrystalline phase in them. Modified glass was obtained by adding B2O3 to andesite basalt. The viscosity of the glass melt was determined on a rotary viscometer. The study of the conditions for the drawing of modified fibers was carried out on a laboratory bench and through theoretical analysis. The temperature of the upper limit of crystallization of the melt Tulc was determined by the quenching method. A mathematical model of the continuous fiber drawing process was used to estimate the crystallization zone. The viscosity of the glass melt with a content of 6 wt.% B2O3 is lower than viscosity of the andesite-basalt melt. The temperature Tulc of modified glass and andesite basalt is the same. Calculations of the speed of movement and the cooling rate of the melt jet during fiber drawing were carried out, which made it possible to determine the glass transition temperature Tgl, the temperature zone of crystallization from Tulc to Tgl and the residence time of the melt in this zone (the time of crystallization). The research results showed that the addition of B2O3 to the composition of glass changed the rheological properties of the glass melt and the conditions for drawing fibers from it. This led to a change in the fibers production interval and the concentration of microcrystalline nuclei in them and affected the thermal stability of fibers.

References


1. Ivanitskii S.G., Chuvashov Y.M., Materials Science Forum, 2024. V. 1113, P. 95-100



Design of grain composition of conductive cluster of multicomponent composite and mechanism for monitoring morphology of its microstructure


Vitaly Petrovsky, Semenyuk Natalia

V.petrovsky@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The electric field strength, and the current density which that promotes the heating of the material, both are also a nonlinear function of the grain composition of the conduc- tive cluster. If the square of current density through the sample is a structure-sensitive parameter for a fine-grained structure, the square of electric field strength shows greater sensitivity in the case of predominance of the coarse microstructure. An empirical for- mula is proposed that relates the concentration of the coarse fraction in percent with the electric current density (in A/mm2), or the electric field strength (in V/cm), at which the surface temperature of 800K is reached (the beginning of the visible dark red glow of in- candescent bodies). It was established that the critical change in the concentration of the coarse fraction, at which the specified color temperature is observed, is 30% Thus, the empirical relations can be applied to calculate the content of the coarse fraction in the microstructure morphology of the conducting cluster on the basis of direct measurements of the electric current density through the resistive material or resistive region.

References


1.Powder metallurgy, 2012, No 5-6, s.73-83 2. Powder metallurgy, 2010, No 5-6, s.67-81



Application of clad powders for the creation of high-density tungsten heavy alloys.


Kyrylo Polishchuk, Anatoly Minitsky

kirillpolishchuk25@gmail.com


National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


Heavy tungsten alloys are used in many industries due to their high specific gravity and are essential in the production of flywheels, counterweights, gyroscope rotors, gyrocompasses, ammunition, X-ray and radiation screens, etc.) However, when manufacturing parts from heavy alloys using powder metallurgy, difficulties arise due to the uneven density distri- bution over the volume of lightweight metals, which negatively affects the performance of the products. Therefore, the aim of this work is to study the effect of the chemical deposi- tion of nickel on tungsten particles to ensure uniform distribution of the low-melting metal when creating high-density heavy tungsten alloys. A composite powder based on tungsten with a nickel layer of 2-3 microns thick was obtained. The study of the particle size distri- bution of the clad powder showed a bimodal particle size distribution, which indicates that not all tungsten powder particles have the same coating thickness. This is due to the fact that the uniformity of the coating deposition depends on the shape and morphology of the initial tungsten particles. The influence of tungsten powder cladding modes on the physi- cal (shape, size, surface morphology, coating thickness), chemical (chemical composition, amount of nickel), and physical and technological properties of clad powders (fluidity, bulk density, density), depending on the concentration of the solution relative to the tungsten powder and on the average size of the tungsten powder, was investigated. The possibil- ity of creating heavy alloys with a uniform distribution of nickel in the material structure, which provides high density and high physical and mechanical properties, is shown. The presented research can be useful in the development of heavy alloys for the military and machine-building industries.

References


1. R.M. German, Tungsten Heavy Alloy Handbook, Metal Powder Industries Federation, Princeton, NJ, 2021. 2.

C. Sauer, A. Heine, K.E. Weber, W. Riedel Stability of tungsten projectiles penetrating adobe masonry – Combined experimental and numerical analysis // International Journal of Impact Engineering, Volume 109, November 2017, Pages 67-77 https://doi.org/10.1016/j.ijimpeng.2017.06.001.



New directions for producing high-strength boron carbide based ceramics for armor protection


Volodymyr Volkogon

VolkogonIPMS@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


To obtain high-strength ceramics based on boron carbide, powders of high dispersion are required since, according to research data, they do not sinter with a particle size of more than 8 microns. Therefore, the search for ways to obtain ultrafine powders is relevant. To propose a method for producing highly dispersed powders by resonance-vortex grinding. An equipment has been developed for implementing the process of producing powders of high-hard materials by grinding using the resonance-vortex method. It is important that there are no rotating or rubbing mechanical parts in the equipment and the working cham- ber, therefore, when grinding materials, there is practically no wear of the chamber mate- rial and “grinding” of foreign additives. The use of the equipment ensures the production of pure crushed powders of the nanodisperse range to obtain hot-pressed ceramics with a fine-crystalline grain structure and improved physical and mechanical characteristics.

References


1. Вишняков Л.Р., Мазна О.В., Нешпор В.О., Коханий В.О., Олексюк О.М. Вплив конструктивно- технологічних факторів на ефективність бронеелементів на основі кераміки, Проблемы прочности, 2004,

№5-6, С.128-135. 2. Скороход В.В., Гнесин Г.Г., Неорганическое материаловедение: Энциклопед.изд. в 2т., 2008, т1., 1152с.



Hot-pressed ceramics for multifunctional purposes based on carbides of refractory compounds


Volodymyr Volkogon

VolkogonIPMS@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Among modern materials, the important role of ceramics is due to the wide range of its physical and chemical properties. The multifunctionality of ceramics makes it possible to use it in various fields of activity – from technology to medicine. Determination of the ba- sic physical and mechanical properties of ceramic composite materials based on carbides of refractory compounds (boron and silicon) depending on their composition and techno- logical features of production. Study of the various additives influence for activating the process of ceramic material formation. The composition and technological conditions for producing multifunctional ceramics based on refractory carbides will be optimized. The optimal choice of additives that activate the process of forming a ceramic material with a homogeneous fine-grained structure and uniform phase distribution will ensure obtain- ing the necessary physical, mechanical and operational characteristics of the composite material, depending on its purpose.

References


1. Srivatsan TS, Guruprasad G., Black D., et. al. Influence of TiB2 content on mocrostructure and hardness of TiB2-B4C composite, Powder Technology, 2005, 159(3), P.161-167



The process of degradation of ceramic balls made of Si3N4-based materials in hybrid bearings


Dmytro Kustovskyi, Oleksand Vasylchuk, Viktor Bilorusets

dskust@gmail.com


V. Bakul Institute for Superhard Materials, Ukraine


The characteristic operating parameters for such equipment, like aviation GTEs, primarily include high speeds of the power shaft rotation and, consequently, high mechanical and thermal loads on the bearings. Ceramic materials, i.e., hybrid bearings, are proposed for the rolling elements in these bearing units. Ensuring the operational safety of bearings of this class, the problem of predicting wear of their components, is extremely relevant. In our work, we investigate the patterns of the degradation process and determine the optimal composition and structure of sintered ceramics for bearing rolling elements. Search for optimal sintering parameters for materials that provide corresponding physico-mechanical properties[1]. Methods for assessing the degradation of investigated materials after oper- ation under specific conditions: Morphometric analysis of wear products. Various types of microscopy and profilometry of damaged surfaces of ceramic balls. Methods for analyzing the operational characteristics of the “in situ” unit[3][4]: Changes in the unit’s vibration spectrum[2]. Changes in the spectrum of acoustic emission. Changes in temperature[2]. Resource prediction based on the analysis of obtained data. Various types of ceramics were considered for the study, among which Si3N4-based material proved to be the best. Microscopy and profilometry revealed changes in surface roughness and the formation of characteristic “material tears” and “pits”, known as pitting corrosion. This is a specific case of fretting corrosion, which occurs during the cyclic movement of two contacting sur- faces. The images show that the pits have a layered shape, torn due to the formation of subsurface cracks. The structure of the materials of worn balls, the surfaces of which are covered with “pits”, has a fragmented structure consisting of particles smaller in size than the original powder used for sintering. The research suggests dividing the operational process into stages: I - cyclic loading of ceramic balls of the hybrid friction pair rolling at high temperatures until the initial damage is detected; II - accumulation of damage in the surface layer due to contact fatigue and initiation of subsurface cracks in ceramic balls; III

  • formation of surface pitting.

    References


    1. International standard ISO 3290-2 . Second edition 2014-09-01 2. Tedric A. Harris, Michael N. Kotza- las. Advanced Concepts of Bearing Technology (Rolling Bearing Analysis, FIFTH EDITION). -CRC Press.- 2006. 3.Tedric A. Harris, Michael N. Kotzalas. Essential Concepts of Bearing Technology(Rolling Bearing Analysis, FIFTH EDITION).- CRC Press.- 2006. 4. Ilaria Ghezzia, Eymard W. Houara Kombaa , Davide Tonazzib , Nathalie Bouscharaina , Gwenole Le Jeunec , Jean-Baptiste Coudertc , Francesco Massia/ Damage evolution and contact surfaces analysis of high-loaded oscillating hybrid bearings / Wear 406–407 (2018) 1–1



    The influence of morphology of starting Al2O3 nanopowders on the microstructure and optical properties of YAG:Sm3+ ceramics


    Arsenii Tymoshenko, Oxana Matvienko, Sergey Parkhomenko, Ihor Vorona, Alexander Tol- machev, Roman Yavetskiy

    arsenii.tymoshenko@gmail.com


    V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


    YAG:Sm3+ transparent ceramics is considered as a promising material for suppressors of amplified emission of powerful YAG:Nd3+ lasers. One of the main tasks during production of optical ceramics is to control the sintering trajectory towards high-density final state,

    i.e. to ensure that densification mechanisms prevail over recrystallization. To obtain a poly- crystalline material with specified properties, it is necessary to control the morphology of the starting powders, the impurity composition of ceramics, and consolidation conditions during sintering. The structural and morphological properties of the powders used as starting materials determine the mesostructure of compacts, i.e. the starting point of the sintering trajectory, and are the first critical parameter that needs to be optimized during synthesis of optical ceramics. The purpose of this work was to study the influence of the morphology of the initial Al2O3 nanopowders on the microstructure and optical proper- ties of YAG:Sm3+ ceramics obtained by reactive sintering. YAG:Sm3+ ceramics were syn- thesized from high-purity commercial α-Al2O3 powders (>99.99%, d=0.15-0.4 μm); Y2O3 (99.999%, d≈5 μm) and Sm2O3 (>99.99%, d=5 μm) by vacuum sintering at 1725°C. To remove residual stresses and restore oxygen vacancies, the ceramics were annealed in air at 1400°C within 15 hours. The effect of particle size composition and morphology of Al2O3 nanopowders on densification efficiency, microstructure and optical properties of YAG:Sm3+ ceramics was studied. It is shown that powder mixtures with uniform parti- cle size distribution provide an optimal sintering trajectory and more effective removal of residual pores compared to powder mixtures with bimodal particle distribution. YAG:Sm3+ ceramics with an average grain size of 25 μm and an in-line optical transmittance as high as 83% at a wavelength of 1064 nm were obtained by the reactive sintering method.

    References


    1. E. R. Kupp, S. Kochawattana, S.-H. Lee, Particle size effects on yttrium aluminum garnet (YAG) phase for- mation by solid-state reaction, J. Mater. Res., 2014, V. 29, No. 19, P. 2303-2311. 2. V. Biasini, J. Hostaša, A. Piancastelli, L. Esposito, A useful approach to understand the origin of defects in transparent YAG ceramics, MRS Communications, 2022, V 12, P. 807–812. 3. A. Krell, H.-W. Ma, Sintering transparent and other sub-μm alumina: The right powder, CFI-Ceramsc Forum International, 2003, V 80, P. 41-45. 4. A. S. Gandhi, C. G. Levi, Phase selection in precursor-derived yttrium aluminum garnet and related Al2O3–Y2O3 compositions, J. Mater. Res., 2005, V. 20, No. 4, P. 1017-1025.



    Effect of Zr4++La3+ sintering aid on the microstructure and optical properties of transparent Y2O3 ceramics


    Anton Balabanov, Ihor Vorona, Oksana Matvienko, Arsenii Tymoshenko, Olexander Tol- machev, Roman Yavetskiy

    balabanovanton964207@gmail.com


    V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


    The synthesis of Y2O3 ceramics using a complex admixture of La2O3+ZrO2 has been de- scribed [1-3]. However, most authors use high concentrations of additives, which promote sintering (6–13 at.%). Such high concentrations of additives can lead to the formation of color centers, disruption of stoichiometry, formation of secondary phases, segregation of additives along grain boundaries, thereby limiting the optical quality and functional char- acteristics of the ceramics. Therefore, recently, the main trend of consolidating optical ceramics is towards reducing the concentration of additives used. Ceramics were synthe- sized with Zr4+ ion concentrations of 0, 1, 1.5, and 2.5 at.%, while the La3+ ion concentra- tion was constant at 0.5 at.%. The average grain size of the unalloyed ceramics is greater than 100 µm and significantly decreases with the introduction of zirconium ions to 5-10 µm. Thus, Zr4+ ions effectively inhibit recrystallization processes during the sintering of Y2O3 ceramics. Ceramics containing Zr4+ ions demonstrate high optical transmittance overall (approximately 78% at a wavelength of 1.1 µm). The introduction of zirconium ions Zr4+ requires compensation of excess charge, which occurs according to the following mecha-

    nisms 1, 2 [4]. 2𝑍𝑟𝑂2+2𝑌 𝑋 ⇔ 2𝑍𝑟 ̇ +𝑂+𝑌 𝑂

    (1) 3𝑍𝑟𝑂

    +4𝑌 𝑋 ⇔ 3𝑍𝑟 ̇ +𝑉 +2𝑌 𝑂

    𝑌 𝑌

    𝑖 2 3

    2 𝑌

    𝑌 𝑌 2 3

    (2) The most energetically favorable is the incorporation of Zr4+ ions into the 24d non- centrosymmetric position of yttrium Y3+ according to equation (1) [4]. Such a defect has a larger specific volume compared to the regular position of the yttrium ion. Another charge compensation mechanism involves the formation of yttrium vacancies (2). Considering the X-ray diffraction data on the reduction of the lattice parameter of yttrium oxide ceramics upon the introduction of tetravalent zirconium ions, it can be concluded that the formation of substitution solid solutions occurs according to mechanism 2. The study shows that the complex addition La3++Zr4+ effectively suppresses the mobility of grain boundaries in Y2O3 ceramics while simultaneously activating diffusion transport along the branched system of grain boundaries.

    Acknowledgments


    Тhe work was carried out during the NFSU project, competition ”Supporting research of leading and young scientists” (2020-2023, state registration number 0123U102633)

    References


    1. L.L. Zhu, Y.J. Park, L. Gan et al. , Ceram. Int. 43 (2017) 13127–13132. 2. P. Deshmukh, S. Satapathy, A. Ahlawat, et al. , J. Mater. Sci.: Mater. Electron. 28 (2017) 11020–11028. 3. L.L. Zhu, Y.J. Park, L. Gan et al. , Ceram. Int. 43 (2017) 8525–8530. 4. Snetkov IL, Balashov VV. , Opt. Mater. 100 (2020) 109617. 5. A.P. Patel,

    C.R. Stanek, M.R. Levy, A. Chroneos, R.W. Grimes, Nuclear Instruments and Methods in Physics Research B 268 (2010) 3111–3113.



    Light dense materials of the AlB12-SiC system


    Pavlo Barvitskyi1, Tetiana Prikhna1, Anastasiia Lokatkina1, Valeriy Muratov2, Victor Moshchil1, Myroslav Karpets3

    barvitskp@gmail.com

    1V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

    2Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    3E.O. Paton Institute of Materials’ Science and Welding, Ukraine

    The work describes the creation hard AlB12C2-based ceramic materials under by hot press- ing and by high pressure-high temperature conditions. The high mechanical performance of the materials we obtained are similar to those of boron carbide, which can be explained by the structural features of B4C and AlB12/ AlB12C2 [1], namely the presence of almost identical structural elements - regular icosahedrons of boron atoms. The possibility of modifying the structure and properties by introducing additives became the reason for conducting research. To obtain the material, sintering of a powder mixture of of αAlB12 and SiC was used. Relatively cheap nanopowders (50-150 nm, with a specific surface area of 21-15 m2/g) α-AlB12 synthesized by PhD. V.B. Muratov (IPM NASU) were used in work [2]. The hot pressing at 30 MPa 1800-1970 оC of two compounds from α-AlB12 nanopow- der with 15 (I) and 20 (II) wt.% SiC addition can result in formation of ceramic elements having according x-ray an-is 88 wt.% AlB12C2-12 wt.% Al2O3-SiC(additives) and 85.5 wt.% AlB12C2-14.5 wt.% Al2O3-SiC(additives) phases compositions respectively. Both materi- als turned out to be light (density rI=2.6 and rII=2.36 g/cm3) and quite dense (porosity PI=5 %; PII=8 %). Samples of the first (I) material were demonstrated HV - 23.3 GPa hardness, fracture toughness K1c - 5.0 MPa•m0.5 and samples of the second (II) material showed HV - 25.6 GPa, K1c - 5.7 MPa•m0.5 accordingly. The sintering under high-pressure apparatus at 4,1 GPa generally allows to reduce sintering temperatures. At a reduced tem- perature to 1700 oC at 4.1 GPa and holding for 8 min, the samples were perfect on the outside, but with a large amount of internal stress. This material had hardness HV - 25.2 GPa and fracture toughness K1c - 4.2 MPa•m0.5 at density rIIІ=2.75 g/cm3 and porosity PIII=5 %. High performance characteristics of the obtained composites can be explained by the formation of solid solutions in the structure.

    References


    1. A. Koroglu, D. P. Thompson, In vacuo production of α-AlB12, C4AlB24, AlB12C2 and Al3B48C2 powders, J. Eur. Ceram. Soc., 2012. P. 3505. 2. P.V. Mazur, O.O. Vasiliev, V.B. Muratov, T.O. Prikhna, P.P. Barvitskyi, V.V. Garbuz,

    V.V. Kartuzov, Composite ceramics based on dodecaboride and aluminum nitride (in Ukrainian), Interuniversity collection «SCIENTIFIC NOTES», 2017. № 58. P. 235.



    Heat-resistant non-combustible material for covering surfaces of special configurations


    Iryna Diduk1,2, Yurii Chuvasov1,2, Tamara Trofimova3

    ididuk2@gmail.com

    1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    2, Ukraine

    3SE STC “Basalt-fibre materials” IPM NAS of Ukraine

    Thermal insulation products are available in a wide range. To produce thermal insulation coatings, both organic and inorganic binders are used to ensure the adhesion of the latter to the coating surface. Basalt Super Thin Fibres (BSTF) with an average diameter of 2 µm; fabric density of 20 kg/m3; thermal conductivity of no more than 0.038 W/m K at a tempera- ture of 25 °C were used for the study. Both inorganic binders (gypsum, cement, bentonite clay) and organic binders (resin FRV 1-A and hardener VAG-3, hydrolysed ethyl silicate, bakelite varnish) were used as binders. The criterion for selecting the composition of the sprayed coating was the need to obtain a fibrous composition with the highest possible thermal insulation properties. Therefore, the research was focused on the development of a binder with high frost and moisture resistance and insignificant changes in physical characteristics over a wide temperature range. The introduction of BSTV into the binder was carried out by mixing it with hydromass. As a result, samples were obtained dispersed reinforced with basalt fibres. The selection of the composition of the thermal insulation samples was evaluated by the coefficient of thermal conductivity, water absorption, and density. Experiments with bentonite clay showed the best results, as the resulting mate- rial has a lower bulk density, is chemically inert, and is environmentally friendly to use. According to the conducted researches it is established that the content of clay binder in clay-fibre compositions should be within the limits from 5 to 30 %, depending on the required density and strength of thermal insulation. Other conditions being equal, with increasing density the thermal insulation properties of fibre insulation at ordinary tempera- ture deteriorate, while at increasing temperature from 300 to 500 C the thermal insulation properties improve with increasing density. It was found that the optimum density is 220 to 250 kg/m3 for the above conditions.

    References


    1. Chuvashov Y.N., Yashchenko O.M., Diduk I.I., Tymchyshyn S.V., Medvedev T.O., Fibrous insulation from rocks of basalt-like composition as an effective means of energy saving [in Ukrainian], Magazine Building materials and produckts. 2018, № 3-4, С.58-61



    Microstructure of heat-resistant nikel alloy after high-temperature heat treatment


    Galina Maksimova, Oksana Vlasova, Mary Golovkova

    oksanavlasova@ukr.net


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    The aim of this work is to study the microstructure of heat-intensive aviation alloy Ni-Co-Al- Cr (GTE) before and after high temperature heat treatment (HTHT) in vacuum at tempera- ture 1280 оС. The alloy GTE is a three-phase system consisting of a γ-solid solution based on nickel with an FCC crystal lattice, dispersion precipitates of the strengthening γ’-phase based on the intermetallic compound Ni3Al (not less than 60-62 vol.%) and monocarbides type MC based on alloying elements (Ta, Nb, W)C. During operation, the structure of the alloy is degraded with the formation of pores, cracks, a change in the crystallographic features of the gratings of the γ- and γ’- phases and their dimensional mismatch with the initial parameters. It was found that the alloy GTE has a dendritic-cellular microstructure with axes of dendrites of the first and second order between which there is an eutectic with precipitates of carbides of the composition (Ta, Nb, W)C, round and significantly elon- gated, and in the form of individual particles ranging in size from 1 to 25 μm and multiple pores 1-10 μm in size. After the HTHT, the γ’-phase cuboids typical of heat-resistant al- loys GTE are formed, the ideality of the shape of which depends on the temperature and exposure at a given temperature. The hardening γ’-phase in the alloy after the HTHT has a different size and shape in the axes of the dendrite and in the interdendritic space. In the interdendritic space the particle size of the γ′-phase is approximately 1.5 to 2 times larger than the size of the γ′-phase in the dendrite body and is 0.2 - 0.8 μm. The thickness of the layer of γ-solid solution is 0.1-0.2 microns. Carbide precipitates of 1 μm and 5 μm in size are observed. In the area of carbide precipitates, the degeneracy of the structure and coagulation of particles of the γ′- phase are fixed. Thus, it was shown in the work that only by high-temperature heat treatment it is impossible to restore the microstructure of the heat-resistant nickel alloy GTE after operation.

    References


    1. G.A. Bagliuk, G.A. Maksimova, A.A. Mamonova, D.A. Goncharuk The Structure and Phase Composition Ac- quired by Fe–Ti–Ni–C Alloys in Thermal Synthesis // Powder Metallurgy and Metal Ceramics. – 2020. – Vol.59. – P. 171-178.



    Sintering and properties of ultrahigh-temperature composites with silicon-containing additives


    Anastasiia Lokatkina1, Tetiana Prikhna1, Pavlo Barvitskyi1, Viktor Moschil‘1, Olexander Borimskyi1, Serhiy Rychev1, Myroslav Karpets2, Semyon Ponomarev3, Anatoliy Bondar2,

    Leonid Devin1

    aslokatkina@gmail.com

    1V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

    2Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    3V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    Materials containing transition metals such as Zr, Hf, Ta, Mo, W, or Nb in conjunction with B, C or N are deemed ultrahigh temperature materials. Our research UHTCs cen- ters on composites founded on ZrB2, ZrC, HfB2, HfC and their solid solutions, with an expanded array of properties compared to existing materials. An elevated level of mechan- ical and damping characteristics is achieved through strong interconnectivity between grain phases due to use starting nanopowders and high and moderate pressures. These ceramic composites show promise for use as construction and wear-resistant materials in high-temperature environments. In order to reduce cracking and fragility of the obtained composites, our work also considered the use carbon- and silicon-containing additives that initiate the formation of laminar structures in the materials. It is known that the interfaces between the layers and the different nature of the 1st and subsequent layers give the struc- ture of the material the ability to quench cracks [1]. Since it is known that the addition of silicon can be used to reduce the consolidation temperature of UHTM, as well as to increase the mechanical stability [2] of such materials by dissolving silicon in the matrix structure [3], we employed silicon-containing additives (MoSi2, Si3N4, ZrSi2 and SiC) in study. We used hot pressing (30 MPa) and high pressure/temperature techniques – recessed-anvil HPA (4.1 GPa, due 1800 oC) when compacting samples. For example, HP samples HfC – 10, 20 and 30 wt.% MoSi2 were characterized by microhardness (HV49) up to 18.7, 19.5

    and 22.1 GPa respectively, and density 10.82, 11.03 and 11.46 g/cm3 respectively. Thus, when we used 20 wt.% MoSi2 to ZrB2, it was possible to reduse the sintering temperature at HP to 1700 oC (more than 200 degrees), and the material showed a microhardness of about 23.7 GPa at density 5.86 g/cm3. At both, composites significantly exceeded pure materials results, at the same conditions synthesizing.

    References


    1. N. Orlovskaya, M. Lugovy, Boron rich solids: Sensors, ultra high temperature ceramics, thermoelectrics, armor. Springer. 2010. P. 1-11. 2. Monteverde F. Ultra-high temperature HfB2–SiC ceramics consolidated by hot-pressing and spark plasma sintering, Journal of alloys and compounds, 2007. V. 428 (1-2). P. 197-205. 3. T.A. Prikhna, P.P. Barvitskyi, A.V. Maznaya, Lightweight ceramics based on aluminum dodecaboride, boron carbide and self-bonded silicon carbide, Ceramics International, 2019. V. 45 (7). P. 9580-9588.



    Effect of chromium carbide on the elastic modulus of modified reaction-bonded silicon carbide


    Mykyta Pinchuk1, Mykola Gadzyra1, Ihor Hnylytsia2

    pinchukipm14@gmail.com

    1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    2Ivano-Frankivsk National Technical University of Oil and Gas, Ukraine

    The study used industrial silicon carbide powders (3, 28, 80, 100)μm and synthesized nano- sized silicon carbide (0.07μm) in the form of its solid solution of carbon and chromium carbide with an average particle size of 0.2μm. Chromium carbide was synthesized in an induction furnace at 1550°C in an argon atmosphere[1]. Chromium oxide and thermo- expanded graphite (TEG) powders were used as synthesis components. X-ray diffraction was performed on an Ultima IV diffractometer in the Bragg-Brentano focusing geometry (CuKα - monochromatic radiation, graphite bent monochromator on the diffracted beam). The values of the first-order stresses were determined by the sin2(ϕ) method for cubic SiC. The measurements at ψ angles of 10, 20, 25 and 30 degrees were performed by the isoin- clination method. Thus, the value of the first-order stresses perpendicular to the sample plane along the [311] crystallographic direction in cubic β-SiC was obtained. When 3 to 10% of highly dispersed Cr₃C₂ is introduced into the composition of the initial batch and in- filtrated with liquid silicon in an argon atmosphere, a decrease in the modulus of elasticity is observed, followed by its increase in reaction-bonded silicon carbide (RBSC). The mini- mum on the curve corresponds to a modifier content of 5%, which corresponds to a modulus of elasticity of 260-280 GPa. This dependence was established on RBSC of different initial fractions of industrial silicon carbide, including synthesized nano-sized silicon carbide. X- ray structural studies have established that the modification process with chromium car- bide leads to the occurrence of internal compressive stresses in contrast to the tensile stresses for unmodified RBSC. It is shown that the dependence of internal stresses on the modifier content correlates with the modulus of elasticity. The minimum value of the modulus corresponds to the maximum value of the internal compressive stresses.

    References


    1. Features of the synthesis of chromium carbide using different forms of carbon //Powder Metallurgy.– 2017.–

    №9,10.– P. 34-39



    Interaction Energy in the Melts of the Fe-Mn-Si-C-Ti System


    Oksana Baranovska, Larysa Romanova, Valentina Sudavtsova, Gennadii Bagliuk

    o.baranovska@ipms.kyiv.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Ferrosilicomanganese (Fe0.21Mn0.62Si0.14C0.07) and silicomanganese are widely used in metallurgical and materials science industries due to their ability to melt at low temper- atures. The addition of reactive titanium leads to the formation of various phases, each possessing unique properties. Thorough study of their thermodynamic properties, particu- larly the melts, is essential for optimizing technological processes. However, determining these properties is complex and time-consuming. Preliminary evaluation using geomet- ric and Redlich-Kister-Muggianu models across concentration ranges is advisable, based on data from limiting binary systems. In the work [1], the thermochemical properties of melts of the Fe-Mn-Si system were determined by calorimetry at 1873 K. Comparison of experimental and predicted thermochemical properties of melts of the Fe-Mn-Si system showed that the best agreement is characteristic for the Redlich-Kister-Muggianu model with a ternary contribution of 300 kJ/mol. Applying the same model, thermochemical char- acteristics of melts of ternary systems Fe(Mn)-Si-Ti, Fe-Mn-Ti, and Si-Ti-C were calculated across the entire concentration range. It was found that the minimum enthalpy of mixing corresponds to the melts of Si-Ti is -70 kJ/mol, Fe-Ti is -20 kJ/mol, and Ti-C is -115 kJ/mol, indicating predominance of pairwise interactions. This is supported by the results of X-ray diffraction analysis (XRD) and electron microscopy studies. However, according to XRD, the synthesis of the mentioned metal-matrix composites (MMCs) results in the formation of the ternary compound Ti3SiС2. According to our modeling, melts of such composition ex- hibit a significant heat release (-110 kJ/mol), suggesting the formation of such a compound is expected. The formation of various binary and ternary phases enhances the strength, hardness, and other properties of the metal-matrix composites.

    References


    1. Bondarenko, T. P., Sudavtsova, V. S., Batalin, G. I., Ulyanov, V. I. Enthalpies of mixing of liquid Fe-Si-Mn alloys

    // Proceedings of the USSR Academy of Sciences. Metals. – 1984. – No. 3. – pp. 81-82.



    Effect of thermo-destructive hardening in epoxy-cement compositions


    Dmitro Starokadomsky1,2, Maria Reshetnyk3,2

    epoxidian@gmail.com

    1V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

    2M.P. Semenenko Institute of Geochemistry Mineralogy and Ore Formation NAS, Ukraine

    3National Museum of Natural History, NAS, Ukraine

    Microscopy shows that morphologically (that is, at the level of microstructures), epoxy- cement represents an aggregative mixture with its own filler structures (in particular, crystal-like formations similar to concrete) and rare air inclusions. It can also be seen that cement is able to form agglomerates in the composition, clusters around air bubbles and certain structures similar to ordered (crystallized) structures. In all cases of filling, we see a noticeable (by 2-3 times), and sometimes a record (for 65% - by 5 times) increase in tearing adhesion. There is also an increase in microhardness and modulus of elasticity under compression (by 1.2-2 times). A high filling of 65 wt% deprives the composite of plas- ticity, turning it into an elastic-brittle state and the modulus of elasticity. The introduction of cement gives an increase in resistance to abrasion, and for 65% it greatly increases the compressive strength (from 700 to 900 kgf/cm2, i.e. from 70 to 90 MPa). The reinforcing effect of cement (the stronger the higher the filling) on the stability of strength in the case of severe heating has been established. After 270 oC processing, the unfilled sample sig- nificantly reduces the strength index, while compositions with gypsum increase them. A particularly high index is given by the maximally filled composite (65%), when the com- pressive strength becomes 2-3 times higher (than for unfilled) and exceeds 100 MPa (1000 kgf/cm2). The plasticizing effect of cement for composites with hard heat treatment (270 oC) was noticed, which is indicated by the microhardness data. The work shows the high prospects of filling epoxies with water-hardening viscosities to strengthen and provide new properties. The revealed effects of thermosetting and thermoplasticization show that such filling gives epoxy previously uncharacteristic properties, which are very important in a number of important applied tasks for industry, repair and creation of new materials.

    References


    1. Starokadomsky D. On Strengthening of Epoxy-Composites by Filling with Microdispersions of SiC, TiN, and Cement // “Composite Materials Engineering Modeling and Technology” Editors: A.V.Vakhrushev, A.K.Haghi. - 2019. – Apple Academic Press, NewYork, - Chapter 4. - P. 49-60. 2. Starokadomsky D., Reshetnyk M. Study of restoration epoxy composites with initial and water-cured cement and gypsum fillers

    Industrial laboratory Diagnostics of materials. - 2021. - 87(8). - 34-41 - DOI: 10.26896/1028-6861-2021-87- 8-34-41. 3. Starokadomsky D, Reshetnyk M. Microfilled Epoxy-composites, capable of thermo-hardening and thermo-plasticization after hard heating (200-300 оС) - for “in-field/offroad” use in bio-,agro-, med- service.// Biomedical J.of Scientific and Technical Research – 2019. - V.19, N 1 - P.14118-14123 - DOI: 10.26717/BJSTR.2019.19.003257



    TO THE DESIGN OF GRAIN STRUCTURE IN CERAMICS


    Galina Oleynik, Andrii Kotko

    oleynik@ipms.kiev.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Design of ceramics with predetermined microstructure is based on the arrangement of con- cordant structure transformations under sintering of selected phase components, whose evolution determines the formation of required microstructure elements, their crystal mor- phology, scale, content, and distribution throughout the volume. Such elements may in- clude grains, intergrain and interphase boundaries, elements of substructure responsible for the appearance of intragrain boundaries,such as dislocation, twinning, domain, and interphase ones, and pores of different types. Knowledge of these mechanisms is the base for design of novel materials an dimprovement of the currentones. The grain structure is a basic material structure component. Based on our research (using TEM with microd- iffraction and SEM with microanalysis) and literature data, general regularities of grain structure formation in ceramics are considered in the course of primary (PR) and collec- tive (CR) recrystallization and during formation of composites under sintering. It’s worth noting that recrystallization in ceramics was first studied by G.V. Samsonov at our Insti- tute. PR in ceramics can occur under different conditions of loading such as free sintering, hot pressing including that under highpressure, uniaxial compression, rolling, friction, etc. The structural mechanisms of the PR evolution in ceramics are similartometals. The for- mation of grain structure in composites is determined by structure transformations due to the contact interaction of phase components; transformations in the grain volume of initial phases (plastic fragmentation, polymorphic transformations, decomposition of solid solutions, twinning, domainization, etc.); transformations in grain boundaries (phase tran- sitions, boundary faceting, etc.). All of them lead to refining grain structure due to the formation of new grains and saturation of the initial ones with internal boundaries result- ing from substructure formation [1].

    References


    [1] Oleynik G.S. Structure formation of ceramic materials. Kyiv: Naukova dumka, 2018, 352 p.



    Consolidation features of ZTA-composite with eutectic composition


    Olena Dudnik1, Iryna Marek1, Maria Smirnova-Zamkova1, Victor Red’ko1, Iryna Martsenyuk1, Viktor Gerashchenko2,3, Tetyana Mosina1, Olexiy Ruban1

    Mega_marekirina@ukr.net

    1Institute of Problems of Materials Science NAS of Ukraine, Ukraine, 03142, Kyiv, str. Omelyan Pritsak (Krzhizhanovsky) 3

    2Institute of Superhard Materials named after V.M. Bakulya of the National Academy of Sciences of Ukraine, Ukraine, 04074, Kyiv, Avtozavodska Street, 2

    3, Ukraine

    ZTA are ceramics in the Al2O3–ZrO2–Y2O3–CeO2 system, which are characterized by high- temperature mechanical strength, heat resistance, wear resistance, oxidation resistance, low thermal conductivity, as well as a small ratio between the coefficients of thermal ex- pansion of ZTA and metals [1]. The mechanical properties of ceramics depend mainly on the amount of ZrO2, its grain size, as well as the ratio of T-ZrO2 and M-ZrO2 and their location in the Al2O3 matrix. ZTA with a composition close to the Al2O3–ZrO2 eutectic are considered as a promising ceramics. The purpose of the research is to determine the con- solidation features of the ZTA composite containing 58.5% (wt.) ZrO2 (Y2O3, CeO2). The composition of a solid solution based on ZrO2 (ZrO2 (Y2O3, CeO2)) (mol.%) is 90 ZrO2– 2Y2O3–8 CeO2. Cold uniaxial pressing were used for the green bodies formation. Sin- tering was carried out in the Nabertherm LTH08/17 laboratory electric furnace at 1500

    °С, 2 hours. Grinds of sintered samples longitudinal sections were made to determine of Vickers hardness. Sintered materials were investigated by X-ray phase analysis (XRF) and scanning electron microscopy. The Vickers hardness was measured using a “Falkon 509” hardness tester (manufactured in the Netherlands) with an indenter load of 300 N (30 kg). The relative density of green bodies 0.46. The relative density of sintered sam- ples was up to 0.97. Phase composition – T-ZrO2, α-Al2O3. A certain orientation of Al2O3 grains was found observed in homogeneous areas, which is a manifestation of the ceram- ics “topochemical memory”, since the composition of the composites corresponds to the eutectic of the binary system Al2O3–ZrO2. Microhardness was 190 MPa, Vickers hardness reached 3.7 GPa, K1c = 7 MPa m 0.5. Using of improved approaches under consolidation of the ZTA eutectic composition will help improve their mechanical characteristics under the microstructural design of high-tech instrumental, structural and functional ceramics.

    References


    1. Otitoju T. A., Okoye P. U., Chen G., Li Y., Okoye M. O., Li S., Advanced ceramic components: Materi- als, fabrication, and applications. Journal of Industrial and Engineering Chemistry.2020.Vol. 85. P.34–65 https://doi.org/10.1016/j.jiec.2020.02.002



    Activation of the ceramic surface to improve its wetting and brazing


    Vladislav Zhuravlyov, Vitalyi Krasovskyy

    vitalkras1955@gmail.com


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Brazing is a physicochemical process that combines adsorption, diffusion, dissolution, wet- ting, capillary flow, adhesion, melting and crystallization. The joining of materials of dif- ferent nature, despite significant progress in this direction, still requires detailed funda- mental research - physical, chemical, technological and improvement of already existing technological processes and solders, development of new multi-component solders, metal- lization coatings and methods of their application D1–4D . The purpose of this work is to find means of reducing the destruction of the surface of a ceramics during its metallization by rubbing with new designs of tools for rubbing, to determine their effect on wetting and brazing modes of oxide ceramics with metal solders. Three new types of Ti tools for grind- ing non-metals using a spongy porous structure and a foil with a thickness of 0.07-0.10 mm have been produced. Samples of A995 and VK94-1 high-alumina ceramics metallized by the proposed method were obtained. It was established that the surface roughness of non-metals affects the composition and microstructure of the applied coating in air. As the roughness decreases, both the density and oxidation of the coating increase. Wetting of ceramics with this coating with PSr72 solder (copper-silver eutectic) was studied, soldered joints were obtained, and the microstructure of the metal-oxide contact zone was studied. Studies of the microstructure of the soldered joint showed that the PSr72 melt permeates the titanium coating, saturates with Ti and wets the ceramics. That is, such metallization does not require coating density and accelerates the saturation of the melt with Ti. The main role of metallization by rubbing is to supply Ti to the base of the solder melt. The advantages of rubbing ceramics with titanium in the form of a porous spongy structure and foil in comparison with a compact metal tool are given. The best results are obtained using a tool made of porous Ti.

    References


    1. Naidich Y. Joining (brazing) of ceramic materials // Ceramic and carbon matrix composites. – London–Glasgow– N.Y.–Tokyo: Chapman and Hall, 1995. – P. 73–95. 2. Naidich Yu.V., Zhuravlev V.S., Chuprina V.G., Strashinskaya

    L.V. Adhesion wetting and formation of intermediate phases in systems composed of a titanium-containing melt and oxide. Powder Metallurgy and Metal Ceramics. 1973. Vol. 12. P. 895–899. 3 Naidich Yu.V., Zhuravlev V.S., Chuprina V.G. Adhesion wetting and formation of intermediate phases in systems composed of a titanium- containing melt and an oxide. Powder Metallurgy and Metal Ceramics. 1974. Vol. 13. P. 236–238. 4. Zhuravlev V.S., Turchanin M.A. Reasons for the formation of various titanium oxide phases upon wetting aluminum oxide with titanium-containing metallic solutions. Powder Metallurgy and Metal Ceramics. 1997. Vol. 36. P. 141–146. Doi: 10.1007/BF02676078



    The influence of the ZrO2 powder dispersion on the solid solutions formation during complex stabilization


    Alina Makudera1, Sergej Lakiza2, Olena Dudnik1, Viktor Red’ko1

    alina.makudera@gmail.com

    1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    2Center of Excellence in Nanophotonics, Advanced Materials and New Technologies Based on Crys- tal, Growth, Poland

    Thermal barrier coatings (TBC) are widely used in modern gas turbine engines to reduce the temperature of metal surfaces in turbine sections and combustion chambers, which can increase their service life and prevent the base material degradation. The coated product must withstand very high temperature, its cyclic change and stresses caused by temperature changes and operating conditions. The standard material of the thermal bar- rier coating (TBC) ceramic layer, ZrO2-based solid solution, stabilized (6−8% (wt.)) Y2O3 (YSZ), has approached the temperature limit of its application (<1200 °C) due to sintering and phase transformation of t’-phase ZrO2 → T-ZrO2 + F-ZrO2 with subsequent formation of M-ZrO2. The creation of a new generation of TBC based on a ZrO2 solid solution com- prehensively doped with REE oxides of the yttrium subgroup (heavy concentrate, HC) is relevant. The goal of the investigation is to determine the influence of the initial ZrO2 powder dispersion on the phase transformations of a ZrO2-based solid solution, compre- hensively doped with a rare earth elements oxides mixture after heat treatment at 1400

    °С. The composition for the investigation was chosen (wt.%): 70 M-ZrO2 + 30 HC. Two M-ZrO2 powders were used: nanocrystalline, obtained by the hydrothermal method, and fine-grained, industry produced. The mixtures were prepared by the ceramic method and fired at 1400 °C for 4-10 hours. Sampling was carried out after 2 hours. According to X-ray phase analysis, it was determined that the formation of T-ZrO2 in a mixture with hydrother- mal M-ZrO2 begins after 4 hours of exposure, and in a mixture with fine-grained M-ZrO2

    – after 8 hours. The final phase transformation M-ZrO2 → T-ZrO2 in both cases was com- pleted after exposure for 10 hours. The first traces of T-ZrO2 were detected in a mixture with hydrothermal M-ZrO2 after 4 hours of exposure, and in a mixture with fine-grained ZrO2 – after 8 hours. Finally, M-ZrO2 disappears after an exposure for 10 hours.

    References


    O.V. Dudnik, S.M. Lakiza, I.M. Grechanyuk, V.P. Red’ko, A.A. Makudera, M.S. Glabay, I.O. Marek, A.K. Ruban, and M.I. Grechanyuk. COMPOSITE CERAMICS FOR THERMAL BARRIER COATINGS PRODUCED FROM ZrO2 DOPED WITH YTTRIUM-SUBGROUP RARE-EARTH METAL OXIDES. Powder Metallurgy and Metal Ceramics. 2021. Vol. 59, Nos. 11-12. Р. 672-680



    A first-principles study of uniaxial compression of boron carbide doped by aluminum in intercosahedral chain


    Vladyslav Bilyi, Oleksandr Vasiliev

    biliy.vl204@gmail.com


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    Boron carbide is a widely used impact-resistant ceramic due to its hardness, low density, and high Hugonio elastic limit, but it is prone to amorphization under high non-hydrostatic loads. Fanchini [1] suggested that the cause of amorphization lies in the (B₁₂)C-C-C boron carbide polytype, namely in the intercosahedral C-C-C chain. Previously, we determined [2] that the substitution of aluminum in the center of the chain is possible, and the most likely configuration is (B₁₂)CAlC. In this work, we consider the simulation of uniaxial com- pression along the intercosahedral chain of (B₁₂)CAlC and (B₁₂)C-C-C. For both configura- tions, we calculate the dependence of uniaxial stress on uniaxial strain and determine the maximum uniaxial stress and elastic strain values. We used a slightly modified method of uniaxial compressing that was described in [3]. The simulation was performed using the Quantum Espresso software package. A 2x2x1 unit cells of (B₁₂)C-C-C hexagonal supercell was constructed along the intercosahedral chain. All central carbon atoms were changed to aluminum and shifted in the same direction. Compression simulations were performed with a step size of 0.01 of the uniaxial elastic strain. Parameters used in the calculation include: kinetic energy cutoff for wavefunctions of 100 Ry, convergence criteria of 10−6 Ry for the self-consistent field and 10−3 Ry/Bohr for forces on the atoms, gamma point only for Brillouin zone, and gaussian spreading of 10−4 Ry. Our results show that the introduction of aluminum into the chain of (B₁₂)C-C-C polytype leads to a decrease in the maximum elas- tic strain (from 0.24 to 0.17) and the maximum uniaxial stress (from 161 GPa to 94 GPa) that the system can withstand. Consequently, the (B₁₂)CAlC configuration has lower me- chanical properties compared to the (B₁₂)C-C-C polytype of boron carbide. No mechanism for improving the characteristics of boron carbide was identified.

    References


    1. G. Fanchini, J. W. McCauley, and M. Chhowalla, ‘Behavior of Disordered Boron Carbide under Stress’, Phys. Rev. Lett., 2006. V. 97, No. 3, P. 035502. 2. O. Vasiliev, V. Bilyi, Y. Zaulychnyy, and V. Kartuzov, ‘Ground states in B4C-Al system’, presented at the HighMatTech-2023, Kyiv, Ukraine, Oct. 2023. 3. S. Aryal, P. Rulis, and W. Y. Ching, ‘Mechanism for amorphization of boron carbide B₄C under uniaxial compression’, Phys. Rev. B 2011. V. 84, No. 18, P. 184112.


    FILMS AND COATINGS



    Model features of films of iron nanoislands that determine electron tunneling


    Kostyantyn Korotkov, Alexander Dmitriev, Anatoliy Kasumov, Arsenii Ievtushenko

    k.korotkov@ipms.kyiv.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Iron island films with a thickness of less than 30 nm undergo rapid surface oxidation in air, which significantly changes their conductivity-related properties, such as the inter-island electron tunneling[1]. The purpose of this work is to study this process. The study of the temperature dependence of the resistivity of oxidized iron films has shown that when the film thickness decreases below 35 nm, a transition from a metallic conduction mech- anism with a characteristic linear shape to an activation (exponential) shape occurs. The activation process in this case may consist of electron tunneling between Fe islands. This means that a film thickness of 35 nm is critical [2] for initiating the process of percolation of the islands. The activation energy of oxidized Fe films is 0.018 eV, which is close to the value of 0.01 - 0.001 eV obtained for unoxidized films. In other words, the activation energy depends mainly on the size of the islands and the distance between them, rather than on their chemical composition. The arrangement of oxidized iron island films on rare earth metal (RΕΜ) oxide leads to a d-f exchange interaction between d-atoms of iron and f-atoms of REΜ. This interaction organizes the magnetic structure of Fe and magnetite, i.e., increases the orientation of electron spins in them [3]. The study showed that the resistivity of oxidized Fe films on REM oxide is lower than on glass due to the higher order of spins in the islands and the absence of energy consumption for spin transfer during electron tunneling between them. In this regard, the tunneling magnetoresistance (TMR) in oxidized Fe films has a negative sign, and when the film is on REM oxide, the TMR value is higher than when it is on substrates made of other materials. Thus, the model of island films allows us to understand the peculiarities of their conductivity under different experimental conditions.

    References


    [1] Moodera, J.S.; Mathon, G., Spin polarized tunneling in ferromagnetic junctions J. Magn. Magn. Mater., 200(1- 3), 248. (1999) https://doi.org/10.1016/S0304-8853(99)00515-6

    [2] Κ.Α. Korotkov, A.M. Kasumov, A.I. Dmiriev MSSE2023, Lviv, 27 – 29 september 2023, p. 17-18


    [3] Yelon A. Interaction in multilayer structures / A. Yelon, Physics of Thin Films, ed. by M.H. Frankomb and R.W. Gorfman, pers. comm. from Engl, M., Mir., 1973, vol. VI, P. 228-333.



    The features and prospects of Mg, Co, Cd and Nd, La, Y doping for ZnO nanostructured films


    Arsenii Ievtushenko1, Vitalii Karpyna1, Denys Myroniuk1, Liliia Myroniuk1, Olena Olifan1, Oleksandr Kolomys2, Ihor Danylenko2, Viktor Strelchuk2, Ivan Koziarskyi3, Eduard Maistruk3

    a.ievtushenko@ipms.kyiv.ua

    1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    2V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    3Y. Fedkovych Chernivtsi National University, Ukraine

    ZnO is a wide band gap semiconductor with a band gap of about 3.37 eV at room tem- perature having a large exciton binding energy of 60 meV that can effectively generate electron-hole pairs by ultraviolet irradiation. It has been taking the focus of researchers as perspective optoelectronic, photovoltaics and photocatalyst [1] nanostructured film mate- rial due to its enormous advantages such as high photosensitivity, high quantum efficiency, low cost, and non-toxicity. It is important that the effects of conditions of deposition, im- purities and native defects on the structure, optical and electrical properties of doped ZnO-based materials is still poorly known [2]. In general, the contribution of various impu- rities and defects in ZnO, which generally control such properties, should be determined. ZnO-doped films with various concentrations of Mg, Co, Cd and Nd, La, Y were grown on Si and glass substrates by atmospheric pressure MOCVD as well as by radio frequency magnetron sputtering, respectively. In this work, we present the results of complex inves- tigations for the influence of different type of impurities on the microstructure by XRD, transmittance, Raman scattering and photoluminescence. The results of photocatalysis activity of nanostructures ZnO films with various doping elements will be also presented and discussed.

    Acknowledgments


    The authors are sincerely grateful to all defenders of Ukraine and emergency workers who made possible publi- cation of the research results.

    References


    1. Karpyna, V., Myroniuk, L., Myroniuk, D. et al., Effect of Cobalt Doping on Structural, Optical, and Photocatalytic Properties of ZnO Nanostructures, 2023, Catal Lett. 2. Korbutyak, D.V., Lytvyn, O.S., Fedorenko, L.L. et al., Photoluminescence spectra of nanocrystalline ZnO films obtained by magnetron deposition technique, J Mater Sci: Mater Electron, 2024. V. 35, P. 583.



    Properties of Multilayer Nitride Coatings Based on Chromium and Niobium


    Iryna Serdiuk1, Viacheslav Stolbovyi1,2, Ruslan Kryvoshapka1, Anatoliy Andreev1, Sergiy Petrushenko3,4, Mateusz Fijalkowski4

    serdukirina05@gmail.com

    1National Science Center “Kharkiv Institute of Physics and Technology”, Ukraine

    2Kharkiv National Automobile and Highway University, Ukraine

    3V. N. Karazin Kharkiv National University, Ukraine

    4Technical University of Liberec, Czech Republic

    In recent years, the development of coatings for different applications is based on the combination of coating components with different physical, mechanical, electrical, optical properties and the complication of the coating structure (1-3). One of important factors affecting the functional properties of multilayer coatings is the state of the interphase boundary between layers with the different phase composition and structural state. This becomes especially significant when the thickness of layers is reduced to tens of nm. Ni- tride multilayer coatings based on chromium and niobium were deposited in a modified installation “BULAT-6” (4). AISI 430 stainless steel samples were used as substrates for deposition of coatings. Three series of coatings were obtained. Planar raster electron microscopic images were obtained using a Tescan Vega 3 SBU. Cross sections were exam- ined in a field emission scanning electron microscope (Zeiss ULTRA Plus). Investigation of multilayer nitride СrN/NbN coatings, which were obtained under different technological parameters of deposition (constant negative voltage on the substrate is from −70 to −200 V, nitrogen pressure in the vacuum chamber is from 0.08 to 0.27 Pa, the total number of layers N (68, 270, 1080), the bilayer period is from 6.7 to 230 nm) made it possible to expand the understanding of the technological parameters’ influence on properties of ob- tained coatings. Cross-sections analysis of multilayer nitride CrN/NbN coatings of three series with different number of layers and bilayer period showed that the total thickness of coatings was 3.6 µm for coatings of the first series, which were obtained by continuous rotation of the substrate holder, and about 8 and 9 µm for coatings of the second and third series, respectively. Elemental analysis showed that obtained coatings of series II and III have high planarity of layers and practically no droplet phase in the volume of multilayer nitride CrN/NbN coatings.

    References


    1. R. A. Koshy, M. E. Graham, and L. D. Marks, Surf. Coat. Technol., 202: 1123 (2007). 2. O. V. Sobol’, A. A. Andreev, V. F. Gorban’, N. A. Krapivka, V. A. Stolbovoi, I. V. Serdyuk, and V. E. Fil’chikov, Tech. Phys. Lett., 38, No. 7: 616 (2012). 3. V. F. Gorban’, R. A. Shaginyan, N. A. Krapivka, S. A. Firstov, N. I. Danilenko, and I. V. Serdyuk, Powder Metall. Met. Ceram., 54, Nos. 11–12: 725 (2016). 4. V. P. Rudenko, V. O. Stolbovoy, I. V. Serdiuk, and K.

    G. Kartmazov, East.-Eur. J. Enterp. Tech., 48, No. 6/1: 66 (2010).



    Structure of nanocomposite FexOy(Fe)SiOx films


    Anatoliy Evtukh1,2, Maria Voitovych1, Olha Pylypova2, Oleh Bratus1

    anatoliy.evtukh@gmail.com

    1V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    2Institute of High Technologies, Taras Shevchenko National University of Kyiv, Ukraine

    Nowadays composite films containing semiconductor or metal nanoparticles embedded into dielectric matrix are of a great interest for the material engineering and variety ap- plications. The composite films with iron nanoinclusions have the special attention due to the advantages of iron and iron oxides such as their availability, non-toxicity, and bio- compatibility. The composite films containing metal nanocrystals in oxide matrix demon- strate the possibility to be used as protective screens from electromagnetic radiation. The nanocomposite FexOy(Fe)/SiOx films were deposited by Ion Plasma Sputtering technique at sputtering of combined silicon-iron target in O2+Ar ambient on Si substrates. In the second stage, FexOy(Fe)/SiOx films were annealed in the argon atmosphere at the temper- ature of range of 300 - 1100 °C during 60 min. To determine the structure and morphology of the films before and after thermal annealing the variety techniques were used. It was established that the structural and phase transformations of FexOy(Fe)SiOx nanocompos- ite films already begin at the annealing temperature T = 300 C in Ar medium. A further increase in the annealing temperature leads to the more intensive process of phase sep- aration. Thermal annealing of FexOy(Fe)SiOx nanocomposite films in the O2 leads to the increase in the intensity of phase separation of the films. During ion-plasma sputtering of the iron target (without Si), the nanocomposite film contains unoxidized iron in the iron oxide matrix FexOy(Fe). As a result of studies of the composition of nanocomposite films by IR spectroscopy, it was established that the largest absorption band is observed in the region of 900-1300 cm-1, which is characteristic of SiOx films. IR bands of metal oxide bonds in the wide range of 400 - 800 cm-1 is practically not registered on freshly sput- tered FexOy(Fe)SiOx samples. This indicates that the iron oxide shell around Fe is quite thin.

    Acknowledgments


    This research was supported by the project “Development of nanocomposite material technology for highly efficient absorption of electromagnetic radiation” of the National Research Foundation of Ukraine (No. 2022.01/0066).

    References


    1. A.Yu. Kizjak, A.A. Evtukh, O.L. Bratus, S.V. Antonin, V.A. Ievtukh, O.V. Pylypova, A.K. Fedotov. Electron transport through composite SiO2(Si) and FexOy(Fe) thin films containing Si and Fe nanoclusters. J.Alloys and Compounds. 2022, 903, P.163892. 2. J.A. Fedotova, A.V. Pashkevich, Ali Arash Ronassi, T.N. Kołtunowicz, A.K. Fedotov, P. Zukowski, A.S. Fedotov, J.V. Kasiuk, Yu.E. Kalinin, A.V. Sitnikov, V.V. Fedotova, A. Evtukh. Negative capacitance of nanocomposites with CoFeZr nanoparticles embedded into silica matrix. J.Mag. Mag. Mat. 2020, 511, P. 166963



    Micro-photoluminescence analysis of the redistribution of NV and SV defects in individual CVD diamond microcrystal with the distance from Si substrate


    Iurii Nasieka1,2, Volodymyr Strel’nitskij3, Oksana Horobei1, Volodymyr Lozinskii1,

    Volodymyr Temchenko1

    yunaseka@gmail.com

    1V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    2National University of Life and Environmental Sciences of Ukraine

    3National Science Center “Kharkov Institute of Physics and Technology”, Ukraine

    The vertical distribution of NV-, NV0 and SiV defects in the individual 60 µm height dia- mond microcrystal of PECVD film grown on Si single crystalline substrate was studied us- ing the micro-photoluminescence method. The presence of N-related defects in the studied crystal is caused by the imperfection of the PECVD vacuum system [1]. The excitation of micro-photoluminescence signals was carried out using the 2.54 eV (488 nm) Ar-Kr laser line focused by the microscope 100x objective in the spot with the diameter equal to 2

    µm. The changes in the shape of room-temperature micro-photoluminescence spectra of diamond micro-crystal measured, depending on the position of focused laser excitation spot along the crystallite height, were analyzed. All spectra were deconvoluted on the ele- mentary Lorentzians including zero-phonon luminescence bands related to each NV-, NV0 and SiV defects and their phonon replicas. Comparing the emission bands intensity the area under the corresponding elementary contours was calculated. It was obtained that the processes of SiV defects formation non-monotonically depends on the distance from Si substrate. At the distances of 2 – 20 µm the concentration of SiV defects increases sharply, then at the distances larger than 20 µm the number of SiV defects decreases. The concen- tration of NV- and NV0 defects monotonically increase with increase in the distance from the Si substrate. The predomination of SiV defects formation at the beginning stages of the crystal growth is explained by the substantial density of carbon divacancies required their formation. With increase in the distance from the substrate the crystalline perfec- tion increases, the number of carbon divacancies decrease and the processes of NV- and NV0 defects formation dominates. The obtained results are important for the developers of CVD diamond film based sensors, which performance is defined by the concentration and distribution of NV-, NV0 and SiV optical centers.

    References


    [1] Iu. Nasieka, E. Strelnitskij, O. Opalev, V. Gritsina, K. Koshevyi, O. Horobei, V. Lementaryov, V. Trokhaniak,

    M. Boyko, Difference in the structure and morphology of CVD diamond films grown on negatively charged and grounded substrate holders: Optical study, SPQEO, 2024. V. 27, No 1. P. 079-089.



    Prediction of nanopowder based tape surface roughness and density from a suspension rheological data


    Serhii Ivanchenko

    s.ivanchenko@ipms.kyiv.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    To create a model for predicting the hydrocluster size in polymer-powder (PVB-BaTiO3) tape casting suspensions, a relation between the Peclet number and viscosity was studied. We used two suspensions with identical composition but different powder size (24 nm and 500 nm). Rheological studies of the dispersion with known-size particles make it possible to calculate the Peclet Number for this dispersion using equations [1], [2]: Pa=(6πr^3 γη)/kT Where r – hydrocluster radius, γ – shear rate, η – viscosity, k – Boltzmann constant, T – temperature The relation between the Peclet number and viscosity fits a power low model Pe=497,66·x^1,744 (nanopowder) and Pe= 1040557,93·x^1,425 (submicron pow- der) By applying this model to a flow curve of the tape casting suspension, where viscosity is known for each shear rate value, it is possible to calculate a hydrocluster diameter

    (d) using the equation: d=2∛(PekT/6πγη). Applying this model to rheological data of the nanopowder suspension showed a change in hydrocluster size from 208 to 60 nm, and for the submicron powder suspension, from 3520 to 924 nm. For a surface with the smallest possible roughness, assuming that the powder particles are spherical and tightly packed, the packing factor (φ) is 0,74. In this scenario Ra = d·(1/8), Rz = d·(1/2). In the case of non-dense packing of spheres (φ=0,68) Ra = d·(3/16), Rz = d·(3/4) [3]. The developed method was applied to compare roughness predictions based on calculated hydrocluster size with experimental data obtained from optical profilometry of the tape’s surface. Pre- dicted roughness for non-dense packing (φ=0,68) of the nanopowder tape is Ra=39 nm and Rz=156 nm. For the dense packing (φ=0,74) Ra=26 nm and Rz=104 nm. Experimen- tal data: Ra=26 nm and Rz=100 nm. For the submicron powder tape Ra=265 nm and Rz=1062 nm (non-dense packing, φ=0,68) and Ra=177 nm, Rz=707 nm (dense packing, φ=0,74). Experimental data: Ra=261 nm and Rz=1076 nm. The error of predicted data is ranging from 1 to 4 %.

    References


    1. T. Iwashita and R. Yamamoto, Direct numerical simulations for non-Newtonian rheology of concentrated par- ticle dispersions, Phys. Rev. E - Stat. Nonlinear, Soft Matter Phys., vol. 80, No. 6, P. 061402, Dec. 2009, doi: 10.1103/PHYSREVE.80.061402/FIGURES/5/MEDIUM. 2. S. Jamali, M. Yamanoi, and J. Maia, Bridging the gap between microstructure and macroscopic behavior of monodisperse and bimodal colloidal suspensions, Soft Matter, vol. 9, No. 5, P. 1506–1515, Jan. 2013, doi: 10.1039/C2SM27104D. 3. S. E. Ivanchenko, Rheological properties and structuring of BaTiO₃ nanopowder-based suspensions during the formation of dielectric layers by tape casting method, IPMS NAS of Ukraine, 257 P., 2023. (In ukrainian)



    Study of the tribological properties of MoN cathodic arc coatings applied to steel


    Viktoriya Podhurska1, Illya Klimenko2, Vitaliy Belous2, Orest Ostash1, Valeriy Ovcharenko2, Galyna Tolmachova2, Igor Kolodiy2, Mykhailo Ishchenko3, Ivan Babayev3, Oleksandr Kuprin2

    podhurskavika@gmail.com

    1Karpenko Physico-Mechanical Institute of the NAS of Ukraine

    2National Science Center Kharkiv Institute of Physics and Technology, Ukraine

    3JSC “Ukrainian Energy Machines”, Ukraine

    The molybdenum nitride coating deposited by the vacuum arc method was one of the first coatings to be used for the protection of machine tools and machine parts. The vacuum arc method allows the deposition of molybdenum nitride with different stoichiometry and crystalline phases of cubic γ-Mo₂N and hexagonal δ-MoN. The binary system of Mo–N offer a high potential to enhance the tribological properties of common hard coatings, owing to their ability to form lubricious oxides (Magnéli phases) at elevated temperatures. However, the application of Mo-N coatings at high temperatures is limited to 500°C [1]. The work aim is to investigate the effect of deposition process parameters (bias voltage), tribopair Al₂O₃, ShKh15 steel, ShKh15 steel with CrN, TiN and MoN coatings and test temperature on the tribological properties of MoN coatings deposited by cathodic arc evaporation method on 15Х12ВНМФ steel. In all coatings deposited on steel at a nitrogen pressure of 0.3 Pa and bias potentials (-30, -50 and -70 V), hexagonal molybdenum nitride δ-MoN was found. The nanohardness of the deposited coatings is at the level of 34.1…34.7 GPa, and the Young’s modulus is 437…471 GPa. The MoN coating on the steel substrate is characterized by low wear at the level of 1.57-2.43·10⁻⁵ mm³/Nm at room temperature tests. An increase in the test temperature to 500 °С leads to a significant (by an order of magnitude) increase in the wear coefficient of 1.83-2.17·10⁻⁴ mm³/Nm. This is due to the low resistance of molybde- num nitride to oxidation at this temperature. Molybdenum nitride oxidizes to molybdenum oxide, which can lead to rapid degradation of the coating under load. The lowest coeffi- cient of friction for the MoN coating was recorded in a pair with a TiN-coated steel ball (0.37), and the lowest wear (10⁻⁷ mm³/N·m) for the MoN – steel and MoN – TiN pairs.

    Acknowledgments


    The work was financially supported by the National Academy of Science of Ukraine (program “Support of the development of main lines of scientific investigations” (KPKVK 6541230))

    References


    1. H. Hazar, Characterization of MoN coatings for pistons in a diesel engine, Materials and Design, 2010. V.31, No.1. P. 624–627.



    Research of corrosion durability of porous materials with protective coatings


    Oleksandr Povstianoi, Nataliia Imbirovych

    povstjanoj@ukr.net


    Bogomolets National Medical University, Ukraine


    The modern stage of the development of materials science is accompanied by the emer- gence of new ideas for the creation and improvement of the technology of obtaining porous materials, which, above all, are aimed at achieving high operational characteristics and re- ducing their cost. To apply a corrosion-resistant protective coating on porous materials, you can use the method of plasma-electrolytic oxidation (PEO), which is one of the ost modern and promising methods of obtaining protective layers on the surface of metals and alloys. The properties of the obtained coatings are determined by the composition of the electrolyte and the modes of the PEO process [1]. To oxidize porous materials, salt solutions (NaCl, NaClO3, NaI, NaNO3 ), acid solutions (HCl, phosphoric, citric, tartaric, and adipic) are used. The most common and simple electrolytes based on KOH solution. Electrolytes based on KOH solution and liquid glass were chosen for research. The synthe- sis of OKP on a zirconium alloy in an electrolyte of 10 g/l of KOH and 15 g/l of liquid glass and a ratio of Ia/Ic = 20/20 ensured the formation of an already pink coating with a fairly high microhardness (16 GPa). Coatings synthesized by the method of plasma-electrolytic oxidation have low porosity. This is explained by the fact that the coating is synthesized at high temperatures, as a result of which the pores melt. Therefore, to increase the porosity, we performed the synthesis at lower temperatures [2]. Comparative data on wear resis- tance showed that the use of porous materials for cleaning low-aggressive environments made it possible due to their improved properties (high chemical resistance, required me- chanical strength, uniform distribution of pores over the entire filtration surface, increased permeability and dirt capacity, due to the provision of volumetric filtration, the possibility of regeneration) to increase the service life of the porous material by 1.5-2.0 times.

    References


    1. Nataliia Imbirovych, Krzystof Jan Kurdzydlowski, Oleksandr Povstyanoy, Valentyna Tkachuk. Features of the formation of ceramic coatings on titanium alloys by plasma-electrolytic treatment with the addition of hydroxya- patite and diatomite. HighMatTech-2023, 2-6 October 2023, Kyiv, Ukraine


    2. Nataliia Imbirovych, Inna Boyarska, Oleksandr Povstyanoy, Krzysztof Kurdzydlowski, Sviatoslav Homon, Leonid Kulakovskyi Modification of oxide coatings synthesized on zirconium alloy by the method of plasma electrolytic oxidation / International scientific session on Аpplied Мechanics XI (17 Аugust 2023). V.2949 (1). P.https://doi.org/10.1063/5.0165655



    Modification of dislocation concentration in GaN:Si films by non-thermal microwave radiation treatment


    Roman Redko1,2, Grigorii Milenin1, Nadiia Safriuk-Romanenko1, Svitlana Redko1

    redko.rom@gmail.com

    1V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    2State University of Telecommunications, Ukraine

    Both photoluminescence spectra and X-ray diffraction of GaN:Si were measured during long term (one month) after processing in microwave field (2.45 GHz, 10 s, p=7.5W/cm2). It was obtained non-monotonous changes of detected characteristics of studied samples. Due to small energy obtained in chosen field alternative resonant mechanism was pro- posed to explain observed features. Transformation of the defect subsystem (impurity- defect complexes destruction and/or detachment and displacement of dislocations) could be realized due to resonant phenomena related with coincidence between the electromag- netic wave frequency and proper frequencies of dislocation oscillations [1] and ion-plasma oscillations of impurity ions [2]. At the resonant frequency with small attenuation, the amplitude and, therefore, the oscillation energy increase sharply. As soon as the oscilla- tion energy becomes higher than the binding energy of defects, the noted changes occur in the state of the latter. The observed features of long-term changes in the PL band in- tensities and dislocations concentration for the semiconductors under investigation after treatments in microwave field has been well described by the offered physical-statistical model of the behavior of defects, which is based on the idea that the corresponding physical processes can be described as random events. This physical-statistical approach allowed us to estimate the diffusion coefficients of defects in epitaxial films of semiconductor com- pounds. Obtained information will be value for understanding sensor system natural aging due to presence external microwave fields

    Acknowledgments


    This work was supported by the National research foundation of Ukraine (Project 2022.01/0126)


    References


    1. G.V. Milenin, R.A. Redko, Physical mechanisms and models of the long-term transformations in radiative recombination observed in n-GaAs under microwave irradiation, SPQEO, 2016. V.19, No. 1. P.14-22. 2. G.V. Milenin, R.A. Redko, Transformation of structural defects in semiconductors under action of electromagnetic and magnetic fields causing resonant phenomena, SPQEO, 2019. V.22, No1. P.39-46.



    Substrate bias influence on the properties of ZnO:Al and ZnO:Al,N films deposited by magnetron sputtering


    Vitalii Karpyna1, Arsenii Ievtushenko1, Olena Olifan1, Sergey Mamykin2, Oleksandr Kolomys2, Viktor Strelchuk2, Peter Lytvyn2, Sergii Starik3, Volodymyr Baturin4, Oleksandr Karpenko4

    v.karpyna@ipms.kyiv.ua

    1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    2V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    3V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

    4Institute of Applied Physics, NAS of Ukraine

    ZnO-based wide bandgap semiconductor oxides with a bandgap 3.3 eV have unique optical and electrical properties that make it promising for transparent electronics, optoelectron- ics and solar cells [1]. Magnetron sputtering (MS) attracts our attention due to the great possibilities for the deposition oxide films with good film adhesion, high deposition rates, film uniformity and stable composition of the deposited films. Traditionally the substrate potential at MS is grounded. The negative or positive potential applied to substrate (sub- strate bias) can influence the film growth as well. As to single-doped ZnO:Al and codoped ZnO:Al,N films the influence of substrate bias on their structure, and optical and electrical properties has not been studied yet in detail. In this work, we focus on the investigation of indicated properties of thin films deposited on Si and glass substrates by radio frequency magnetron sputtering in a layer-by-layer regime. Sample characterization was carried out by traditional instruments: X-ray diffraction, EDX spectroscopy, Raman scattering, pho- toluminescence, IR Fourier transform spectrometry, optical and electrical measurements. The experimental results will be presented and discussed. Shortly, the best crystalline quality demonstrates ZnO:Al films grown with the highest negative voltage bias of -30V. We have found that applying a negative bias voltage to the substrate during film growth allows us to increase the conductivity of ZnO:Al films three times compared to zero-biased ZnO:Al films deposited at the same conditions. ZnO:Al,N films show very high specific re- sistivity due to acceptor complex formation. It must be noted that all deposited ZnO:Al and ZnO:Al,N films demonstrate a high transparency of over 80 % with an optical band gap in the range 3.34-3.42 eV for ZnO:Al films while ZnO:Al,N films demonstrate band gap near

    3.15 eV.

    References


    1. A. Ievtushenko, O. Baibara, M. Dranchuk, O. Khyzhun, V. Karpyna, O. Bykov, O. Lytvyn, V. Tkach, V. Baturin, O. Karpenko, Phys. Status Solidi A, 2023. V.220, No. 2. P. 2200523



    (TiZrNbHfTa)B2 films deposited by DC magnetron sputtering


    Volodymyr Ivashchenko, Alexei Onoprienko, Olena Olifan, Alexei Sinelnichenko, Alexander Marchuk, Andrii Kovalchenko, Dmytro Vedel, Petro Mazur

    onopr@ipms.kiev.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Recently, a new approach was proposed for alloy design which involves the mixing of sev- eral transition metal elements. These alloys were termed as “high-entropy alloys” (HEAs) [1]. Along with bulk materials the researches are carried out with HEA films or coatings doped with non-metal elements. In the present work we investigated the effect of nega- tive substrate bias on the structure and mechanical properties of HEA- boride films. The films were characterized in terms of their microstructure, chemical bonds status, hardness and tribological properties. The (TiZrNbHfTa)B films were prepared by magnetron sput- tering of the Ti-Zr-Nb-Hf-Ta-B target manufactured by hot pressing method of TiB2, ZrB2, HfB2, NbB2, and TaB2 powders. The films were deposited with negative bias voltage in the range of 0÷200 V applied to the substrates. The XRD analysis showed that the peaks in XRD patterns of as-deposited films cannot be recognized as the either diboride constituent of sputtered target. This allows suggestion on the formation of single-phase solid solutions of transition metal diborides used. The films are nanocrystalline with grain size calculated by Sherrer formula increased from 9.5 nm to 40 nm when increasing bias voltage from 0 to ‒200 V. The XPS results indicated formation of the following bonds in films: Ti-B, Ti- B-O, Zr-B, Nb-B, Hf-B, Hf-O, Ta-B. The Knoop hardness increased with bias voltage in the range of 0÷ -150 V, and then decreased with further increase of bias voltage. The results obtained clearly show that multi-element films exhibit an essentially higher hardness as compared to the most of bulk binary diborides used for deposition of (TiZrNbHfTa)B films presently studied. The tribological tests showed that the film deposited with Ubias= -200 V exhibited the least value of friction coefficient. This fact agrees with radical decrease in films hardness deposited under this condition.

    References


    1. J.-W. Yeh, S.-K. Chen, S.-J. Lin, J.-Y. Gan, T.-S. Chin, T.-T. Shun, C.-H. Tsau, S.-Y. Chang, Nanostructured high- entropy alloys with multiple principal elements: novel alloy design concepts and outcomes, Adv. Eng. Mater., 2004, V. 6, №5, P. 299-303.



    Laser-enhanced electrodeposition of composite nickel coatings


    Valentyna Tytarenko

    tytarenko.valentina@gmail.com


    National Technical University Dnipro Polytechnic, Ukraine


    The solution to the surface hardening problem is the modification of the metal matrix with particles of the dispersed phase to obtain composite electrolytic coatings [1, 2]. The pur- pose of this work is to study the effect of laser radiation on the process of co-deposition of metal ions and ultradispersed diamond particles, structure, mechanical and protective properties of electrodeposited composite nickel coatings. Electrodeposition of compos- ite coatings was carried out from sulphate nickel-plating electrolyte out under external exposure to radiation from a CO2 gas-discharge laser generating in a continuous mode at a wavelength of 10,6 μm at a laser radiation power of 25 W. X-ray microanalysis was performed using a JSM-64901LV scanning electron microscope (Japan). The increase in the concentration of smaller ultradispersed diamonds (UDD) particles (~0,25–1 μm) in the coating formed under laser-assisted deposition is due to the potential gradient and rise in the diffusion coefficient. The increase in the flux density of complexes formed as a re- sult of the adsorption of metal ions on the surfaces of UDD particles leads to an increase in oversaturation at the crystallization front. The formed coating is reached by smaller size UDD particles that block the growth of nuclei of the crystalline phase, which leads to the formation of a more densely packed coating and changes the cross-sectional growth structure from columnar to microlayer. The formation of finer crystalline coatings and change of cross-sectional growth structure from columnar to microlayer at laser-assisted deposition process resulted in improvement of mechanical and protective properties of carbon-containing nickel coatings (coating microhardness increased from 1800-1950 MPa to 2500-3700 MPa, corrosion resistance increased 2 times, and the wear of coatings de- creased 3 times).

    References


    1. Meihua L., Hongnan L., Dongai W., Bing L., Yan S., Feihui L., Yunlan G., Linan L., Lianjin L., Wengang Z. Effect of Nanodiamond Concentration and the Current Density of the Electrolyte on the Texture and Mechanical Properties of Ni/Nanodiamond Composite Coatings Produced by Electrodeposition. Materials, 2019. V. 12, No.

    7. P. 1-19. 2. Tytarenko V.V., Zabludovsky V.A., Shtapenko E.Ph., Tytarenko I.V. Application of pulse current for producing a strengthening composite nickel coating. Galvanotechnik, 2019. V. 4. P. 648–651.



    Magnetic properties of electrolytic alloys of refractory metals at cryogenic and near-Curie temperatures


    Yuliya Yapontseva1, Oksana Gorobets2, Tetyana Maltseva1, Valeriy Kublanovsky1

    juliya_yap@ukr.net

    1V. I. Vernadsky Institute of General and Inorganic Chemistry of the NAS of Ukraine

    2National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

    Alloys of refractory metals (W, Mo and Re) with iron group metals have valuable prop- erties, such as heat and corrosion resistance, hardness and magnetic properties, which ensures their use in the aerospace, nuclear and electrical industries. Only by electrodepo- sition from aqueous solutions is it possible to obtain thin alloys coatings with the ability to accurately control the chemical composition, structure and thickness of the resulting deposits [1]. This paper presents a study of the influence of the nature of the refractory metal (W, Mo, Re) on the magnetic properties of electrolytic alloys with cobalt at cryogenic temperatures and temperatures close to the Curie point. The CoW, CoMo and CoRe alloys were deposited from citrate-pyrophosphate electrolytes and contained 80 at.% cobalt. The magnetic characteristics of the alloys were studied using a “Vibrating Magnetometer 7404 VSM” Lake Shore Cryotronics Inc., USA in magnetic fields of up to 5 kOe. At room tem- perature, saturation magnetization differs significantly for alloys of different refractory metals [2]. Ms for the CoW alloy increases more than threefold upon cooling, and for the CoMo and CoRe alloys the increase is less than 20%. With increasing temperature, the sat- uration magnetization should constantly and monotonically decrease, which is what take place with the CoRe alloy, for which Ms decreases to almost zero. For CoMo and CoW al- loys, magnetization does not reach zero and begins to increase at a temperature of ~600K. It is known that cobalt exists in two allotropic modifications with transition temperature is 700K. Both cobalt modifications have different magnetic properties and can be present simultaneously in electrochemical coatings. Possible reasons for changes in the magnetic properties of alloys are: phase transition; enlargement of crystallites when heated; for- mation of an electrolytic alloy, including the formation of phases of solid solutions and intermetallic compounds.

    References


    1. N. Eliaz, E. Gileadi, Induced Codeposition of Alloys of Tungsten, Molybdenum and Rhenium with Transition Metals in Modern Aspects of Electrochemistry, edited by C. Vayenas et al., Springer, 2008. V.42, P.191 2. Y. Yapontseva, V. Kublanovsky, T. Maltseva, O. Gorobets, R. Gerasimenko, Y. Troshchenkov, and O. Vyshnevskyi, Effect of Magnetic Field on Electrodeposition and Properties of Cobalt Superalloys, J. Electrochem. Soc., 2022. 169, 062507



    Application of Samsonov’s configuration model in establishing the influence of the electronic structure of d-metals on thermal electron emission of WBa cathodes


    Olena Makarenko, Iryna Podchernyaeva, Olha Hetman

    olena.maluhina@gmail.com


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Electron emission from WBa-cathodes is carried out from an adsorbed layer of barium and oxygen atoms on W or other d-metal adsorbents. When films of the d-metals Re, Os, Ir and Ru are deposited on the emitting surface, the work function φ decreases by 0.2 eV; and in the case of Pt, Pd and Au, it increases by 0.2 eV. The aim of the work is determine the effect of the electronic structure of d-metals on the work function of the WBa cathode using the Samsonov configuration model. According to Samsonov’s configuration model, the formation of a condensed state is accompanied by the division of valence electrons into two subsystems: localized and itinerant electrons. Free-filled and half-filled configurations such as s2, s2р6, d0, d5, d10 are the most energetically stable in the spectrum of configu- rations.According to Samsonov’s model, oxygen atoms are electron acceptors, since they tend to fill the valence orbitals 2s22p4 with electrons in the energetically more stable state of 2s22p6. Ba atoms are electron donors, donating their 6s2 valence electrons to oxygen to form surface dipoles Ba+– O- with ionic bonds. These dipoles reduce the work function of

    1. Re, Os, Ir and Ru atoms have unpaired electrons in the orbitals d6 and d7, which, upon energy absorbing, transform into sp-valence states and can be electron donors, ensuring the maximum population of sp - states of oxygen. As a result, the degree of polarizability of Ba+ – O- dipoles on the surface of these adsorbents increases, which further reduces φ. Pt, Pd and Au atoms with stable d9 and d10 orbitals have a reduced donor ability and do not have the effect of reducing the work function. Сonclusion. The main mechanism of emission of WBa cathodes is the donor-acceptor interaction of adsorbed atoms among themselves and with the adsorbent, leading to the formation of polarized dipoles responsi- ble for the escape of electrons into vacuum.

      References


      1. D. Norman, R.A. Tuck, H. B. Skinner, P. J. Wadsworth, T. M. Gardiner, I.W. Owen, C. H. Richardson, and G. ThorntonR Surface structure of thermionic-emission cathodes. / //. Physical Review Letters. February 1987. 58(5):519–522, https://doi.org/10.1103/PhysRevLett.58.519.



    The effect of refractory fillers on improving the tribotechnical characteristics of antifriction self-lubricating polymer composite coatings


    Eugen Pashchenko, Denys Savchenko, Oksana Kaidash, Svitlana Kukharenko, Sergiy Sko- rokhod, Roman Kurganov

    oksana.kaidash@gmail.com


    1. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


      To increase reliability and increase maintenance intervals, it is advisable to switch to dry friction units. The most promising is the development and application of self-lubricating polymer composite coatings. This is especially important for the operation of materials in conditions of high sliding speeds and high temperatures (up to 250 °C). The residual strength of the adhesive bond of the synthesized composites with the materials of the friction pair parts after heat treatment (300 °C, 100 h) was evaluated for 3 composite compositions based on polyimide binding synthesized polyimides with structurally rigid fragments (diallyl esters of dicarboxylic acids, crosslinked with ferrocene derivatives ) with fillers – finely dispersed (0.3–3 μm) SiC, TiCN, TiB2 powders. The developed anti- friction self-lubricating coating made of diallyl esters of dicarboxylic acids synthesized by us, cross-linked with ferrocene derivatives, has a coefficient of friction on steel in the range of 0.02–0.05 with wear resistance 4–5 times higher than that of polytetrafluoroethy- lene. According to the results of bench tests, the most promising composition of the self- lubricating composite was determined. Based on the set of characteristics, a polyimide bonded composite based on ferrocene dicarboxylic acid, filled with finely dispersed silicon carbide powder, was chosen. The use of the developed self-lubricating coating based on high-molecular polymer binders with high mechanical strength with axial cross-linking of oligomeric chains by molecules of diallyl ester of ferrocene dicarboxylic acid leads to an increase in tribotechnical characteristics, which consist in a significant reduction of the coefficient of dry friction in solid lubricating coatings at high loads.



      Effect of electric arc spraying of Al-4.6Cu-1.5Mg coating and its plasma-electrolyte treatment on the corrosion resistance of Mg-8.5Al alloy in 3% NaCl


      Halyna Veselivska, Volodymyr Hvozdets’kyi, Mykhailo Student, Khrystyna Zadorozhna

      fminanu1978@gmail.com


      Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine


      Since magnesium alloys, which are widely used in the automotive and aviation industries, have insufficient wear resistance and corrosion resistance, there is a need to improve their surface properties. The purpose of the study was to determine the effect of the Al-4.6Cu- 1.5Mg aluminium electric arc coating (EAC) sputtered at an air jet pressure of 1.2 MPa and the synthesized plasma-electrolyte oxidized (PEO) layer on it on the structure and some characteristics of the Mg-8.5Al magnesium alloy. The microstructure of the coated samples was studied on an EVO 40XVP scanning electron microscope. X-ray phase analysis of the coating was performed in Cu-Kα radiation. The porosity of the PEO layers was determined by hydrostatic weighing. Microhardness was determined using a microhardness tester. The electrochemical characteristics in 3% NaCl of the obtained coatings were determined from the potentialdynamic polarization curves taken at a scanning speed of 1 mV/s. EAC with a thickness of ~ 250 mm on magnesium alloy have a typical lamellar structure and are porous. The lamellae are separated by thin Al2O3 oxide films. In the process of PEO, the electrolyte penetrates the EAC, accumulates in its pores, and the formation process occurs as if from its middle, the lamellae disappear and its porosity is reduced by half. This increases the microhardness of the coating. Electrochemical studies have shown that the PEO of an aluminium coating additionally increases its corrosion resistance in NaCl solution by more than an order of magnitude [1]. Thus, spraying coatings from aluminum alloys onto magnesium alloys, followed by PEO treatment, makes it possible to produce oxide ceramic coatings with properties on par with PEO coatings on aluminum alloys. This integrated approach makes it possible to create oxide ceramic coatings on other alloys that are not subject to PEO treatment, such as steels and cast irons.

      References


      [1] M. M. Student, I. B. Ivasenko, V. M. Posuvailo, H. H. Veselivs’ka, A. Yu. Pokhmurs’kyi, Ya. Ya. Sirak, V. M. Yus’kiv // Materials Science. – 2019. – 54, №6 – Р. 899–906.



      Properties of HVAF-coatings from Al-Cu-Fe quasicrystalline alloy


      Yuriy Yevdokymenko, Mykola Iefimov, Gennadii Frolov, Kateryna Iefimova

      yevd@meta.ua


      Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


      Alloys of Al-Cu-Fe system containing quasicrystalline ψ-phase are perspective as thermal barrier, wear-resistant, corrosion-resistant and anti-adhesion coatings. Typically, such alloys are compositions of quasicrystalline and crystalline metallic phases, making them similar to metal ceramics [1]. Until now, high quality thermal spraying coatings from alloys containing ψ-phase more than 70 %(mass) have not been obtained due to its low plasticity at temperatures up to 500°C, phase transition to λ-phase and β-phase at 880°C and narrow area of existence in the diagram of states. The spraying was carried out by HVAF spraying method with liquid fuel burner GVO-RV with flow rate control of two-phase flow parameters, developed in IPMS of NASU [2]. The burner provides spraying powder with temperature 700-1000°C and velocity at least 500 m/s. In this mode the formation of coatings occurs from solid particles due to their plastic deformation. This allows to avoid typical for traditional technologies heating of particles above Tm=1080°С leading to oxi- dation and evaporation of aluminum resulting in the alloy composition leaving the limits of the existence of ψ-phase. The coatings were sprayed from water atomized Al63Cu25Fe12 powders [3] of fractions +20/-40 µm, +40/-63 µm, +63/-80 µm with the content of ψ-phase 65-75 %(mass). The content of ψ-phase in the coatings was ±5 % compared to powder; in some cases it came to 90 %. The thickness of the coatings is a controllable parameter and may reach 1000 µm. The porosity of coatings on substrates from copper, titanium, steels, aluminum alloys is 4-8 %. The adhesive/cohesive strength of coatings on 1044 steel substrates, determined by the pin method equals to 31±3 MPa. The thermal conductiv- ity coefficient of Al-Cu-Fe coatings increases from 1.9±0.15 W/(m×K) at 20°C to 2.2±0.2 W/(m×K) at 800°C. The resistance of coatings to erosion at jet-abrasive processing is at the level of an HVAF-coating made of stainless steel AISI 301.

      References


      1. H. Parsamehr, T. Chen, D. Xi et al. Thermal spray coating of Al-Cu-Fe quasicrystals: Dynamic observations and surface properties. Mater. 2019. No. 8. 100432 2. Yu. Evdokimenko, V. Kysel et al. Burner for High-Velocity Air- Fuel Spraying of ZrB2 Based Coatings for Aerospace Technics. ”Space Research In Ukraine 2014-2016” Report to COSPAR. Kyiv. Akadempereodyka. 2016. P.114-117. 3. N.A.Yefimov. Powders with quasicrystalline structure. In: Neikov O.D., Naboychenko S.S., Yefimov N.A. Handbook of non-ferrous metal powders. Amsterdam: Elsevier. 2019.



    Influence of additives of bronze powder Cu-10Al-4Fe on the tribological characteristics of coatings based on the Ni-C system


    Oleksiy Kushchev1, Oleksandr Umanskyi1, Oleksandr Terentiev1, Victor Varchenko1, Tetyana Chevichelova1, Valery Brazhevskyi2, Oleksandr Chernyshov2, Ruslan Kostiunik3

    aleks.tmu@gmail.com

    1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    2Composite Systems Ltd, Ukraine

    3National Aviation University, Ukraine

    Use of plasma coatings of nickel-clad graphite powder (Ni-C) is promising for use as abrad- able sealing materials [1, 2, 3]. To expand the areas of application of Ni-C powder coatings, it is advisable to use them in combination with bronze [4]. For this purpose, it is proposed to use bronze powder Cu-10Al-4Fe, which has proven itself well as an antifriction material. The purpose of this work was to study the influence of the amount of bronze additives Cu- 10Al-4Fe on the tribological characteristics of coatings. Plasma coatings were applied in an open atmosphere on a UPU-3D installation in a protective chamber using a Metco F4- MB plasma torch. Plasma-forming gases - mixture of argon and hydrogen. Coatings were obtained from Ni-C powder, as well as mixtures of Ni-C and Cu-10Al-4Fe powders with bronze additives in amounts of 5, 25 and 50 wt. %. Tribological tests were carried out on an M-22M friction machine. It has been established that with increasing bronze content, the abrasion resistance of the coating increases. Introduction of Cu-10Al-4Fe powder in an amount of 50% wt. into the main Ni-C powder led to a significant (~ 7 times) increase in the wear resistance of the resulting coatings. Additive 5% wt. Cu-10Al-4Fe into Ni-C powder leads to a decrease in the friction coefficient from 0.60 to 0.54. On samples of Ni-C+ 25% Cu-10Al-4Fe, a decrease in friction coefficient to 0.50 was observed Increasing the bronze content to 50% wt. in the powder composition made it possible to reduce the friction coefficient to 0.35. Conclusions. With an increase in the bronze content of Cu-10Al- 4Fe to 50% wt. in the composition of Ni-C based powder, there is a tendency to improve the basic tribological characteristics of coatings, namely, wear resistance increases by 7 times, and the value of the friction coefficient decreases from 0.60 to 0.35. This makes it possible to significantly expand the scope of application of the Ni-C +Cu-10Al-4Fe material in aviation and space technology.

    References


    1. F. Ghasripoor, R. Schmid, M. Dorfman, Abradable coatings increase gas turbine engine efficiency, Materials World 5 (1997) 328 2. P. Dowson, M.S. Walker, A.P. Watson, Development of abradable and rubtolerant seal materials for application in centrifugal compressors and steam engines, Sealing Technology 12 (2004) 5 3. R. Rajendran, Gas turbine coatings – an overview, Eng. Fail. Anal. 26 (2012) 355–369 4. J.M. Guilemany, J. Navarro,

    C. Lorenzana, S. Vizcaino, J.M. Miguel, Tribological behaviour of abradable coatings obtained by atmospheric plasma spraying (APS), International Thermal Spray Conference, Singapore 2001, pp. 1115–1118



    Influence of ultrasonic impact treatment on structure and properties of 3D-printed metals and alloys


    Andrii Burmak1, Svitlana Voloshko1, Mykhailo Voron1,2, Andrii Orlov1

    abyrmak@gmail.com

    1National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

    2V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

    In a modern world, additive manufacturing of metal products has reached significant vol- umes and variety of applied alloys. 3D-printing technologies make it possible to obtain parts with reduced mass, increased reliability, single products, experimental parts and elements designs with complex geometry and configuration [1]. Disadvantages of metal parts additive manufacturing include anisotropy of chemical composition and properties, non-equilibrium structural-phase state, structural micro- and macrodefects and some other features, that require post-processing of as-printed products. Most often, heat treatment and its combination with microforging or intensive surface plastic deformation are used for this purpose [2]. The manuscript provides an analytical review of the advantages of using ultrasonic technologies to support 3D-printing and post-processing of additively manufac- tured products. Special attention is paid to ultrasonic impact treatment (UIT). The equip- ment for providing UIT is compact, energy-saving and easy to use. It is noted, that this technology makes it possible to effectively reduce surface defects of printed parts, increase its hardness and fatigue strength. At the same time, nanostructuring and changes in the structural and phase state of the modified layers are also occurred. It is also noted, that UIT may provide surface strengthening to a depth of ~500 μm, saturating it with alloying elements and compounds, and for conventionally produced parts, like as–cast, deformed and powder sintered – it is significantly more effective than most other similar methods [3]. The prospects of using ultrasonic technologies to improve quality and level of oper- ational and mechanical characteristics of additively manufactured metal parts, including the needs of aircraft construction, are outlined.

    Acknowledgments


    This study was financially supported by the NMinistry of Education and Science of Ukraine (Projects 0124U001001).

    References


    1. Additive laser technology. – 2024. https://alt-print.com/aircraft-industry 2. Рalinkas I., Pekez J., Desnica E., Rajic A., Nedelcu D., Materiale plastice, 2022, Vol. 58, No 4, pp. 238-249 [in English]. http://dx.doi.org/10.37358/MP.21.4.5549 3. Mordyuk B.N., Voloshko S.M., Zakiev V.I., Bu rmak A.P., Mo- hylko V.V., Journal of materials engineering and performance, 2021, Vol. 30, No 3, pp. 1780-1795 [in English]. https://doi.org/10.1007/s11665-021-05492-y



    Finite element analysis of scratch test of films on substrate


    Irina Valeeva1, Ivan Goroshko2

    valeeva@meta.ua

    1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

    2Taras Shevchenko National University of Kyiv, Ukraine

    Scratch test is an important investigation method which is used to evaluate mechanical properties of materials and structures, adhesion of coatings, etc. The stress distribution in the sample is the most important information, which affects its deformation, damage and fracture of the sample material. Simulation of scratch tests of samples with refrac- tory, hard and other coatings or different film-substrate systems allows us to understand which type of load occurs between the substrate and the coating [1], which type of load affects delamination of coatings. Numerical simulation allows us to study the influence of each parameter on the scratch test results. The aim of this study is to implement finite element simulation of the elasto-plastic deformation during scratch test using ANSYS soft- ware. Finite element analysis of scratch test was applied to film-substrate systems. Large deformation in scratch zone causes essential difficulties that related to mesh distortion, which leads to an abort of solution process. To overcome these computational difficulties, researchers use special approaches and software. 3-D model was built taking into ac- count the symmetry and enlarging elements further from the contact zone. NLADAPTIVE procedure in ANSYS was applied to overcome the distortion of finite elements at large de- formation. Finite element analysis shows significant material movement occurring in the structures during scratch test. The moving indenter creates grooves and ridges on the sur- face of the sample which profile depends on the elasto-plastic properties of the materials. The fields of displacement, stress, and strain in the film-substrate systems were obtained as a result of scratch test simulation.

    References


    1. Li, J., Beres, W. Three-dimensional finite element modelling of the scratch test for a TiN coated titanium alloy substrate. Wear, 2006. V. 260, No. 11-12. P. 1232‑1242.



    Effect of heat treatment in hydrogen on the phase formation processes in nanoscale FePt and FePtPd films and their Raman spectra


    Mykola But1, Daria Horodnycha1, Ruslan Shkarban1, Maksym Barabash1,2, Tetiana Verbytska1, Iurii Makogon1

    verbitska@kpm.kpi.ua

    1Educational and Research Institute of Materials Science and Welding National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”

    2Technical Center, N.A.S. of Ukraine

    Nanoscale films based on FePt(Pd) layers with an ordered L1o structure have a promis- ing application both for ultra-high-density magnetic information carriers and for future spintronics devices. The purpose of these studies was to determine the effect of the heat treatment in the hydrogen environment and the Pd addition on the phase compo- sition and structure of the films and their optical properties. Equiatomic Fe50Pt50 and Fe50(Pt0.75Pd0.25)50 films with a total thickness of 15 nm were obtained by magnetron sputtering on a SiO2/Si(001) substrate at room temperature. After deposition, the films were annealed in a hydrogen environment at temperatures of 400 - 700 °С for 1 h. The processes of the A1 into L1o phase transformation were investigated by X-ray diffraction, RHEED method and Raman scattering spectroscopy. The ordered L1o phase in both films begins to form at 400 °C. As the temperature rises, its amount increases. The Pd addition activates the ordering process and contributes to increasing the ordering degree, the for- mation of (001)-textured grains up to a temperature of 650 °C, but does not affect the size of the FePt or FePtPd coherent scattering regions. It was found that after annealing to 700 °C, only the L1o phase is observed in both films. The change in the Raman spectra confirms the presence of embodied hydrogen in the films and а two-phase state (A1+L1o) in the films up to a temperature of 650 °C, inclusive. The variation in Raman spectra and the luminescence effect are manifested in different structural combinations of FePt and FePtPd films. The non-linear change in the intensity of the Raman spectra is the basis for the appearance of forced Raman scattering effects. Enhancement of luminescence by the film allows to identify the structural A1into L1o phase transformation dynamics.

    Acknowledgments


    The authors would like to thank Prof. M. Albrecht from Augsburg University (Germany) and workers for sample preparation, assistance in investigations and discussion of results . This work was financially supported by DAAD the Grant ID 57630758

    References


    1. Levchuk L., Shkarban R., Kotenko I., Graivoronska K., Fesenko O., Lukianenko I., Verbytska T., Makogon Iu., Barabash M. Changes in Raman spectra upon formation of ordered L1o FePd phase during annealing in vacuum and in hydrogen atmosphere, Thin Solid Films. 2024. V. 789. 1402000. https://doi.org/10.1016/j.tsf.2024.140200



    Effect of caesium adsorption on the emission properties of (110) and

    (100) molybdenum surfaces


    Sviatoslav Smolnik1, Mykola Shevchenko1, Iryna Galstian1, Yevheniy Tsapko1, Evgen Len1,2

    sviatsmol@gmail.com

    1G. V. Kurdyumov Institute For Metal Physics, N.A.S. Of Ukraine

    2Kyiv Academic University, M.E.S. and N.A.S. Of Ukraine

    Improving the emission properties of refractory metals electrodes of thermionic converters (TECs) and emission electronics devices is a challenging but important task [1]. Optimiza- tion of the electron work function (φ) for the electrodes’ surfaces and the back current from the anode to the cathode, i.e., the reduction of the electron reflection coefficient (K) from anode, in particular due to the presence of adsorbates (in our case, caesium) on its surface, is one of the main aspects of this task’s solution. To understand the emission properties formation in refractory metals, it is important to obtain their atomically clean surfaces and to study these properties on them. In the present work, the influence of cae- sium adsorption on the work function of atomically clean surfaces (110) and (100) of Mo single crystal obtained by high-temperature annealing and on the reflection of electrons from them is considered. To control the state of the surface and measure φ the methods of total current spectroscopy I(U) and contact difference of potentials, correspondingly, are used. Dependences of coefficient K on adsorbed caesium concentration (n) were de- termined from the experimental current-voltage characteristics (CVC) in the region of the first maximum, which corresponds to slow electrons with energies of 1-2 eV. It is shown that the electron reflection coefficient from the anode takes the largest value (0.42) for a pure (Cs-free) Mo (110) face, and for a similar Mo (100) face it acquires the smallest value (0.05). Formation of Cs monolayer on both investigated surfaces (at n ≥ 6.2·1014 at/cm2) leads to the levelling of the difference between different faces and to attainment of saturation for K (~0.21).

    Acknowledgments


    This work was supported by the project No. 0123U102275 of the National Academy of Sciences of Ukraine.


    References


    [1] S. V. Smolnik, I. M. Makeieva, V. M. Kolesnyk, M. O. Vasylyev, M. Ya. Shevchenko, I. Ye. Galstian, and E. G. Len, Effect of Deformation on the Electronic Properties of the W(110) Single Crystals Surface Before and After Different Types of Surface Treatment, Metallofiz. Noveishie Tekhnol., 2023, 45, No. 9: 1083—1097.



    Electrochemical synthesis, properties and applications of rhenium alloys with iron-group metals


    Oksana Bersirova1,2

    oksana.bersirova@chgf.vu.lt

    1Vilnius University, Lithuania

    2V.I.Vernadsky Institute of General and Inorganic Chemistry NAS of Ukraine

    The main objective of this study is to develop an efficient method for the electrochemi- cal synthesis of multifunctional (magnetic and electrocatalytic) dense films of Re alloys with Iron-group metals. Heat-resistant alloys, often called superalloys, are based on the iron subgroup with refractory metals (Mo, W, Re) and are capable of operating under ex- treme temperature and power conditions in aggressive environments. A combination of unique physical and chemical properties makes these superalloys promising for use in high- technology sectors such as aviation, nuclear power engineering, electronics, biomedicine, and heterogeneous catalysis [1-4]. Today, the largest application of materials based on Re alloys is in superalloys, accounting for 70%, especially for jet aircraft engine turbine blades. The primary focus of this study is the Fe-Re system. The electrochemical method for pro- ducing Fe-Re alloys enables the obtainment of coatings with controlled chemical composi- tion, structure, and thickness. Several key aspects determine the interest in studying the electrodeposition of Fe-Re alloys: i) depending on the alloy composition, they exhibit either soft or hard magnetic properties; ii) they have potential uses in microelectromechanical systems; iii) Re alloys show electrocatalytic properties in the HER. To achieve the main goal of this research, new stable, non-toxic complex electrolytes for Fe-Re alloy deposition were developed. The dependencies of the chemical composition, current efficiency, and surface morphology on the complex composition of the electrolyte (concentrations of the main components of the bath, their ratio, pH), electrolysis regimes (current density, poten- tial), and the influence of the hydrodynamic regime were studied. Fe-Re coatings with Re content in the alloy ranging from 1 to 90 wt.% were obtained, depending on the concen- trations of the main components of the developed electrolyte and deposition conditions.

    Acknowledgments


    This research has received funding through the MSCA4Ukraine project, which is funded by the European Union (Project No. 1233494).

    References


    1. Naor, A., Noam Eliaz, N., Gileadi, E., Electrodeposition of Alloys of Rhenium with Iron-Group Metals from Aqueous Solutions, ECS Transactions, 2010, V.25, No.29, P. 137-149. 2. Cesiulis, H., Sinkevičiute, J., Bersirova, O., Ponthiaux, P., Tribocorrosion testing of self-passivating molybdenum and tungsten alloys containing cobalt and iron, BALTTRIB 2009 - 5th Int. Conference, Dedicated to Lithuanian Millennium, 85th Anniversary of Lithuanian University of Agriculture, and 60th Anniversary of Department of Mechanical Engineering, Proc., 2009, P. 253–

    258. 3. Bersirova, O., Bilyk, S., Kublanovsky, V., Electrochemical synthesis of Fe-W nanostructural electrocatalytic coatings, Materials Science, 2018, V.53, No.5, P. 732-738. 4. Bersirova, O., Kublanovsky, V., Nickel-Rhenium Electrolytic Alloys: Synthesis, Structure, and Corrosion Properties, Materials Science, 2019, V.54, No.4, P. 506– 511.


    LOW-DIMENSIONAL MATERIALS AND NANOSTRUCTURES



    Game-changing key materials in the future sustainable economy


    Petre Badica

    -


    National Institute of Materials Physics, Romania


    Human history has periods defined by a game-changing key material, e.g. stone, bronze, iron, silicon, polymers, etc. although other materials were also used at the same time. What should the key materials of the future look like? To answer this question we assess in a multidisciplinary manner ancient materials revealing unexpected features specific for modern materials, thus showing that learning from the past can be rewarding. As a case study we also analyze multifunctional properties of MgB2, a 2D-like compound, and learn on its potential as a sustainable material based on our results and literature data.

    References



    Dispersion and polarization control of light with metasurfaces and related applications


    Artem Hrinchenko1, Sergey Polevoy2, Oleh Yermakov1

    oe.yermakov@gmail.com

    1V. N. Karazin Kharkiv National University, Ukraine

    2O. Ya. Usikov Institute for Radiophysics and Electronics NASU, Ukraine

    Two-dimensional (2D) materials offer unique opportunities for photodetection, light emission, energy harvesting, and enhanced light-matter interactions. Even more interest brings the artificially engineered 2D micro- and nanostructures with on-demand proper- ties paving the way for a plethora of specific applications and devices including lensing, holography, imaging, polarimetry, biosensing, etc. The rapidly developing use of 2D nanostructures poses new challenges for their proper engineering and novel applications. This work focuses on the metasurfaces, which are two-dimensional periodic arrays of subwavelength scatterers. Despite their ultrathin thickness, metasurfaces efficiently ma- nipulate light acting as the refractors, reflectors, absorbers, lenses, antennas, polarizers, etc. In this work, we develop new approaches and advanced algorithms for metasurfaces engineering and study their electromagnetic properties in both far- and near-field. The developed analytical and semi-analytical models are used to investigate the metasurfaces for the modification of the Brewster angle [1], the diffractionless in-plane transfer of the localized light [2], the development of planar polarizer [3], the enhanced light coupling and light-matter interactions.

    References


    1. O. Yermakov, Phys. Rev. A, 2024. V. 109, No. 3. P. L031502. 2. A. Hrinchenko, O. Yermakov, J. Phys. D: Appl. Phys., 2023. V. 56, No. 46. P. 465105. 3. S. Polevoy, O. Yermakov, IEEE Antenn. Wireless Propag. Lett., 2023. V. 22, No. 8. P. 1962.



    Simulating the vacancy saturation effect on phase changes in irradiated nanoparticles using the steady-state approach in chemical rate theory


    Aram Shiirnyan1, Yuriy Bilogorodskyy1, Oleksiy Krit2

    aramshirinyan@ukr.net

    1V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    2“Laboratory of composite materials of nuclear-hydrogen energy”, Department of nuclear-physical research, Institute of Applied Physics of National Academy of Sciences of Ukraine

    The objective of the research is to propose a thermodynamic approach to describe the ef- fects of vacancy saturation on the phase stability of solid nanoparticles during irradiation and to employ the steady-state approach in chemical rate theory to account for radiation defect concentrations. The research is applicable for polymorphic phase transitions in met- als (Mo, V, W, Ti, Tl, Zr) and amorphization in ceramics (SiC, TiC). The study demonstrates, via simulation, the potential for radiation-induced α-phase to β-phase transitions and sta- ble radiation zones in initially crystalline nanoparticles. Two model approximations are considered: one resembling iron-like metals with a polymorphic phase transition (α phase is bcc, β phase is fcc) and another resembling SiC-like ceramics with amorphization (α phase is cubic or hexagonal polytype of SiC, β phase is amorphous SiC). Parameters for irradiation include 1MeV ions with fluences ranging from 10 15 to 2×10 16 ions/cm² per second, and defect generation rates (K V ) of nearly 10 -3 - 10 -4 dpa/s for metals and 10

    -12 dpa/s for ceramics, vacancy migration energies of 1-2eV for metals and nearly 4eV for crystalline ceramics. Our model study reveals that very small α-phase (bcc) particles are unstable, and α to β phase transformations can occur independently of irradiation. How- ever, in certain scenarios, nucleation of the β-phase necessitates a significant additional energy change, leading to a low probability of α to β phase transition. For larger particle sizes and lower temperatures, α to β transformation becomes impossible regardless of irra- diation. Crystalline ceramic materials generally demonstrate notably higher values for the energy of vacancy migration. This implies that the impact of radiation on phase transitions in ceramics is likely to be more significant. In contrast, nanoscale metals exhibit greater resistance to irradiation and thus may be recommended for nuclear materials.

    Acknowledgments


    The work is the part of Research of the Laboratory of Composite Materials for Atomic-Hydrogen Energy at the Institute of Applied Physics of NASU (RC 0122U001445, supervision of Ph.D. Aram Shirinyan).

    References


    1. Shirinyan A.S., Bilogorodskyy Y.S., Krit O.M. Phase stability of spherical fe nanoparticles under radiation saturation with vacancies // Nuclear Physics and Atomic Energy. 2022. vol. 5. p. 125–129.



    Tunnel Magnetic Contacts with Perpendicular Anisotropy of Magnetic Electrodes as Promising Elements for Recording Information


    Mykola Krupa

    lidermyk@i.ua


    Institute of Magnetism of the National Academy of Science and Ministry of Education and Science of Ukraine

    This paper describes the mechanism of appearance of magnetic capacitance in tunnel mag- netic contacts with magnetic electrodes that have perpendicular anisotropy, presents the results of measurements of the value of tunnel magnetic resistance and tunnel magnetic capacity in Tb22-DCo5Fe73/Pr6O11/Tb19-DCo5Fe76 tunnel contacts. The work also pro- vides a structural diagram of the construction of an information carrier based on tunnel magnetocapacitance and describes the principle of recording information in such a struc- ture. This paper describes the mechanism of appearance of magnetic capacity in tunnel magnetic contacts with magnetic electrodes that have perpendicular anisotropy, presents the results of measurements of the value of tunnel magnetic resistance and tunnel mag- netic capacity in Tb22-DCo5Fe73/Pr6O11/Tb19-DCo5Fe76 tunnel contacts, where the value of tunnel magnetic resistance is almost 120%, and the value of the tunnel magnetic capac- ity is more than 110%. The work also provides a structural diagram of the construction of an information carrier based on tunnel magnetocapacitance and describes the principle of recording information in such a structure.

    References


    [1] H. Kaiju, S. Fujita, T. Morozumi and K. Shiiki. Magnetocapacitance effect of spin tunneling junctions. Journals of Applied Physic 91 (2002) 7430. https://doi.org/ 10.1063/1.1451754



    Production of nanosized composite Al-Fe-Cr-Ti alloys and study of their plasticity in the temperature range


    Mykola Iefimov, Nataliia Zakharova, Svitlana Chugunova, Alex Golubenko, Victor Gon- charuk

    m.yefimov@ipms.kyiv.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    The technological and physical principles for production of nanoquasicrystalline (QC) Al- Fe-Cr-Ti alloys with an increased level of mechanical properties have been developed. The strength of such alloys is provided by high hardness and elastic modulus of QC well as their stability up to relatively high temperatures, plasticity ensured by a special deforma- tion mechanism of QC nanoparticles. The Al₉₄Fe₂.₅Cr₂.₅Ti₁ rods are produced using powder extrusion technology without sintering of high-pressure water atomization powders. The TEM and X-ray methods were used to characterize the structure; the mechanical properties were studied by indentation and mechanical tensile tests. To characterize the behavior of the Al-Fe-Cr-Ti alloys the physical plasticity characteristic δ* was first used. δ* is the ratio of plastic strain to total strain was determined both during indentation and tensile tests. It is shown that Al-Fe-Cr-Ti alloys have record heat resistance characteristics at 300°C: UTS 345MPa, YS 330MPa and elongation 4%, with elongation at room temperature up to 8%. The Al-Fe-Cr-Ti alloys show an abnormal behavior of plasticity change: with in- creasing temperature, the value of elongation δ gradually decreases in the temperature range of 20-300°C and with further temperature increase its value increases again. This effect is explained by the processes of dynamic strain aging (DSA) which is the instabil- ity of the plastic flow of materials associated with the interaction of moving dislocations and diffusing dissolved substances [1]. The δ(δн) determined both tensile and hardness tests behave without taking into account the DSA effect: δ and δн increase monotonically with increasing temperature. Thus, the use of δ* to characterize the change in plasticity in the temperature range allows us to characterize the plasticity of the material without considering the processes accompanying its fracture.

    References


    1. S. Pedrazzini, M. Galano, F. Audebert, G.D.W. Smith, Elevated Temperature Mechanical Behaviour of Nanoqua- sicrystalline Al93Fe3Cr2Ti2 Alloy and Composites, Materials Science and Engineering A, 2017. V.705. P.352- 359.



    The mixed spin-1/2 and spin-1 Ising model for CuInP₂S₆ ferrielectrics


    Ruslan Yevych, Vitalii Liubachko, Viacheslav Hryts, Mykola Medulych, Anton Kohutych,

    Yulian Vysochanskii

    vysochanskii@gmail.com


    Institute for Solid State Physics and Chemistry, Uzhhorod National University, Ukraine


    The temperature behavior of Sn₂P₂S₆ ferroelectrics was previously explained using the Blume-Capel model with pseudospin S=1, which is related to the local three-well poten- tial for spontaneous polarization fluctuations [1-3]. For CuInP₂S₆ crystals, the mixed Ising model [4,5] can be applied, which uses spins s=1/2 and S=1. These spins are related to the ordering dynamics of Cu⁺ cations in the double-well potential (pseudospins s=1/2) and to the displacive dynamics of In³⁺ cations in the three-well local potential (pseudospins S=1). The quantum anharmonic oscillator model was used to accomplish this task. Additionally, data from a light scattering study is incorporated. Based on the temperature dependence of the pseudospin fluctuations spectra, it can be concluded that the In³⁺ cations experience anharmonic disordering/displacements in the local asymmetric three-well potential at tem- peratures below 150K. This leads to specific lattice anharmonicity phenomena, which alter the temperature behavior of the lattice vibrations and cause the thermal expansion coef- ficient to change sign. Additionally, a dipole glassy appearance is observed in the deeply cooled ferrielectric phase. The contribution of Cu⁺ cations to the calculated pseudospin fluctuation spectra is found to evolve with heating above 150K, supporting the activation of ionic conductivity in CuInP₂S₆ crystals. Notably, the same species, namely copper cations, participate in both spontaneous polarization and ionic conductivity creation. The variation of the pseudospin fluctuation spectra upon heating to 150K is consistent with the softening of the Raman low-frequency spectral lines related to the cationic sublattice dynamics of indium and a broadening of the spectral line above this temperature due to the disorder in the copper sublattice.

    Acknowledgments


    We acknowledge support from the Horizon Europe Framework Programme (HORIZON-TMA-MSCA-SE), project

    № 101131229, Piezoelectricity in 2D-materials: materials, modeling, and applications (PIEZO 2D).


    References


    1. Yevych R., Haborets V., Medulych M., Molnar A., Kohutych A., Dziaugys A., Banys Ju., Vysochanskii Yu., Low Temp. Phys., 2016, v. 42, p. 1155–1162. 2. O.V. Velychko, I.V. Stasyuk. Phase Transitions, 2019, v. 92, p. 420-429. 3. R. Erdem, S. Özüm, N. Güçlü. Condens. Matter Phys., 2022, v. 25, No. 4, p. 43707. 4. W. Selke, J. Oitmaa. Phys.: Condens. Matter, 2010, v. 22, p. 076004. 5. W. Selke and C. Ekiz, Phys.: Condens. Matter, 2011, v. 23, p. 496002.



    Properties of PTFE-Based Nanocomposite Reinforced With Micro- And Nano-Fibers of SiС


    Petro Sylenko, Denys Andrushchenko, Mykola Yakubiv, Victor Horban, Yuriy Solonin

    lazerandr@gmail.com


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Significant enhancement of mechanical properties of polymer materials, in particular poly- tetrafluoroethylene (PTFE), is achieved by using various fillers. In the proposed work, the creation of antifriction composites of the PTFE type reinforced with micro- and nanofibers of SiC is considered. For this purpose, a suspension of PTFE F-4D (TU 6-05-1246-81) and nanofibers manufactured at the IPM NAS of Ukraine [1] were used. 15 weight percent of SiC. X-ray diffraction studies were performed on a DRON-3M diffractometer. All diffrac- tograms showed three distinct lines at the double reflection angles of 36, 60, and 72 de- grees, which correspond to the cubic phase of β-SiC. Transmission electron microscopy (TEM) studies were conducted on a M-200 microscope. TEM analysis of the images indi- cates that silicon carbide fibers with sizes ranging from submicron to hundred nanometers are uniformly distributed in the polymer matrix. The mechanical properties of the PTFE- based composites depending on the content of silicon carbide fibers were determined by automatic indentation method. It was found that increasing the content of silicon carbide fibers in the composite leads to a significant increase in mechanical characteristics. Tri- botechnical tests of samples were conducted on the M-22M friction machine at a constant sliding velocity of 0.5 m/s and variable loads. Hardened steel 45 rollers were used as counterfaces. The introduction of five percent nanofibers into PTFE leads to a several-fold increase in the wear resistance of the composite. With an increase in the volume fraction of fibers to 15% at a given sliding velocity and pressure of 0.5 MPa with a sliding distance of 3-5 km, wear is absent.

    References


    1. P.M. Silenko, A.N. Shlapak, T.V. Tomila, et al., Fe-catalyzed synthesis of SiC nanofibers from methyltrichlorosi- lane, Inorganic materials, 2008. 44. P. 388-394.



    The impact of low-temperature heat treatment on the structural and magnetic properties of Pt-(Au-)-Co heterostructures


    Roman Pedan1, Pavlo Makushko2, Yurii Yavorskyi1, Oleksandr Dubikovskyi3, Andrii Bodnaruk3, Andrii Burmak1, Denys Makarov2, Igor Vladymyrskyi1

    roman1pedan@gmail.com

    1Igor Sikorsky Kyiv Polytechnic Institute, Ukraine

    2Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Germany

    3V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

    Utilizing thermally induced diffusion-driven structural phase transformations in multilayer stacks to facilitate the formation of functional thin films holds significant promise for ap- plications in nanoelectronics and magnetic data storage [1]. Ferromagnetic thin films de- rived from Co-Pt alloys serve as a foundational material science platform for the advance- ment of diverse applications, including spin valves, spin orbit torque devices, and high- density data storage media. In the present study Co(10 nm)/Pt(10 nm)/substrate, Pt(10 nm)/Co(10 nm)/substrate, Co(10 nm)/Au(2 nm)/Pt(10 nm)/substrate, and Pt(10 nm)/Au(2 nm)/Co(10 nm)/substrate stacks were obtained by magnetron sputtering onto SiO2/Si(001) substrate. The as-deposited stacks were annealed in a vacuum at temperatures of 150 °C

    – 550 °C for 30 minutes. Structural and magnetic properties were studied by secondary ion mass spectrometry (SIMS), X-ray spectroscopy, transmission electron microscopy, X- ray diffraction, and VSM magnetometry. Diffusion coefficients were estimated using the Hall–Morabito and Fisher–Whipple approaches. It is demonstrated that the layer stacking significantly impacts the diffusion rate at temperatures where the diffusion is dominated by grain boundaries. The heat treatment of thin-film stacks enhances coercivity, attributed to short-range chemical ordering effects. Introducing an additional Au intermediate layer increases the coercive field of annealed sstacks by modifying exchange coupling between magnetic grains at grain boundaries.

    References


    1. A. Hafarov, O. Prokopenko, S. Sidorenko, D. Makarov, I. Vladymyrskyi, L10 ordered thin films for spintronic and permanent magnet applications, Modern Magnetic and Spintronic Materials. NATO Sci. Peace Secur. B: Phys. Biophys., 2020. P. 73-84.



    Photoluminescent studies in the wide temperature range (20-300 K) of hydrogen and nitrogen doped C₆₀ fullerite.


    Viktor Zoryansky, Peter Zinoviev

    zoryansky@gmail.com


    1. Verkin Institute for Low Temperature Physics and Engineering of NAS of Ukraine


      The optical properties of C₆₀ single crystals saturated with hydrogen and nitrogen molecules were studied by the spectral-luminescence method in the temperature range of 20–230 K. The saturation was carried out under a pressure of 30 atm at different temper- atures from 200 °C to 550 °C. Early it have been established of C₆₀ fullerite intercalated with H₂ [1] and N₂ [2] molecules that the temperature limit of the adsorption crossover is about 300 °C and 420 °C, respectively (transition from the diffusion mechanism of intercalation - physisorption to chemical interaction - chemisorption). At saturation temperatures higher than this temperature limit the process of chemical interaction of H₂ or N₂ impurity molecules and the C₆₀ matrix occurs with the formation of a new chemical compounds - C₆₀Hₓ and (C₅₉N)₂. For the first time we present the results of the photoluminescent properties of new C₆₀ fullerite intercalated with N₂ and H₂ molecules

  • hydrofullerite C₆₀Hₓ and biazafullerite (C₅₉N)₂. In C₆₀Hₓ compound the integrated radiation intensity is independent from temperature has been recorded. This behavior of integrated radiation intensity have been explained by the absence of an orientational phase transition and the transition to a glassy state in hydrofullerite. In (C₅₉N)₂ compound the temperature dependence of the integral radiation intensity has been registered. Also in biazafullerite the low temperature quenching of photoluminescence has been detected. The new effect of low-temperature quenching of photoluminescence has been explained by the appearance of effective capture centers of the excitons which occurs as a result of the chemical interaction of N₂ impurity molecules and the C₆₀ matrix, and the non-radiative deactivation of electronic excitation [3].

References


    1. K. A. Yagotintsev, I. V. Legchenkova, Yu. E. Stetsenko, P. V. Zinoviev, V. N. Zoryansky, A. I. Prokhvatilov, and

  1. A. Strzhemechny, Low Temperature Physics, 2012. T.38. P.952 2. I. V. Legchenkova; K. A. Yagotintsev; N. N. Galtsov; V. V. Meleshko; Yu. E. Stetsenko; A. I. Prokhvatilov, Low Temp. Phys., 2014. T.40. P.685 3 . P. V. Zinoviev and V. N. Zoryansky, Low Temp. Phys., 2022. T.48. P.268


    SYNTHESIS AND PROPERTIES



    On changes in the mechanism of chemical affinancy in the synthesis of compounds of refractory metals with oxygen group elements


    Viktor Solntsev, Gennadii Bagliuk, Tetiana Solntseva, Kostiantyn Petrash

    KostyaPetrash1990@gmail.com


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Thermodynamic interpretation of chemical affinity as the tendency for chemical compo- nents to interact was given by Théophile de Donde. It manifests itself in systems up to the threshold of thermodynamic stability. In work [1], during the decomposition of unsta- ble chalcogenides of refractory metals and during their interaction with metals of IVA, VA groups and chromium, both the existence and synthesis of unstable compounds of these metals with chalcogen type MeX3, MeX4 were established. An increase in the amount of chalcogen is observed during decomposition. To clarify the nature of the mechanisms of formation of chalcogenides beyond the threshold of thermodynamic stability, their in- teraction in complex metal systems containing the active reducing agent aluminum and diselenide was studied. The compacts were sintered in vacuum at temperatures above the existence of these chalcogenides. When studying the distribution of elements after sinter- ing, the existence of titanium compounds of various stoichiometries, which is the basis of the composition, was established. No compounds of aluminum with selenium were found. Beyond the limit of thermodynamic stability, compounds are formed with metals that are less prone to interact with chalcogen. Moreover, these compounds are formed and exist at temperatures significantly higher than the region of their existence in the individual state. This phenomenon is due to the formation of a dissipative structure with a characteristic feature of dynamic stability. This type of stability occurs far from thermodynamic equilib- rium due to the appearance of autowave processes in the reacting system. In such systems, self-oscillatory reactions occur, which was shown in [2, 3]. Namely, due to the catalytic properties of the seven elements, the manifestation of autowave properties is determined. Thus, the chemical affinity in these systems is determined by the tendency for the catalytic reproduction of atomic elements of the oxygen group.

    References


    1. V.P. Solntsev. Development of work in the field of creating wear-resistant materials for structural purposes of space technology // Powder metallurgy, 2014.- No. 3/4.- P. 30-38. 2. V.P. Solntsev, V.V. Skorokhod, V.L. Baranov,

G.O. Frolov, T.O. Solntseva. Mathematical modeling of highly nonequilibrium topochemical reactions in powder systems // Powder metallurgy, 2001.- No. 5/6.- P. 1-7. 3. V.P. Solntsev, V.V. Skorokhod, V.L. Baranov. Model of self-oscillatory topochemical reaction in an open system metal - diatomic gas // Reports of NASU - 2001 - No. 12

- P. 83-87.



Features of sintering compositions based on titanium with refractory compounds


Viktor Solntsev, Gennadii Bagliuk, Tetiana Solntseva, Kostiantyn Petrash, Alevtina Ma- monova, Galina Molchanovska

kostyapetrash1990@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Titanium-based powder alloys are of particular interest for aerospace engineering due to their high specific strength, corrosion resistance and other properties. To increase wear resistance, it is usually necessary to introduce solid phases and compounds that ensure heterogenization of the structure and, accordingly, localize the development of plastic de- formation. The materials that most effectively resist wear are those that form dissipative structures during sintering [1-3]. They arise in complex physicochemical systems due to the competition of chemical reactions that are observed during interaction with refrac- tory compounds with the participation of unstable chalcogenides, which are sources of excitation of autowave processes. Being constantly excitable systems in which continuous transfer is observed due to self-organization processes, it should be expected that acti- vation of sintering will be observed in such compositions. Molybdenum diselenide and disulfide were introduced into titanium compositions with compounds of various natures. Thus, when sintering in systems with titanium carbide, titanium boride and titanium ni- tride, the introduction of diselenide and molybdenum disulfide leads to significant com- paction. When they are introduced into compositions with covalent compounds (B4C, BN, SiC, Si3N4), activation of titanium-based compositions is observed both in certain concen- tration regions of covalent compounds and chalcogenides. Threshold concentrations are observed at which shrinkage gives way to growth. This is due to the activation of the pro- cess of interaction of the covalent compound with titanium. In this case, corresponding ti- tanium compounds are formed with elements that form one or another covalent compound, for example borides, nitrides, carbides, and auto-dispersion of the material structure oc- curs.

References


1. V.P. Solntsev. Development of work in the field of creating wear-resistant materials for structural purposes of space technology // Powder metallurgy, 2014.- No. 3/4.- P. 30-38. 2. V.P. Solntsev, V.V. Skorokhod, V.L. Baranov,

G.O. Frolov, T.O. Solntseva. Mathematical modeling of highly nonequilibrium topochemical reactions in powder systems // Powder metallurgy, 2001.- No. 5/6.- P. 1-7. 3. V.P. Solntsev, V.V. Skorokhod, V.L. Baranov. Model of self-oscillatory topochemical reaction in an open system metal - diatomic gas // Reports of NASU - 2001 - No. 12

- P. 83-87.



Thermodynamics and Chemical Ordering of Glass-Forming Liquid Cu–Co–Ni–Ti–Zr, Cu–Co–Ni–Ti–Hf Alloys


Mykhailo Turchanin1, Pavlo Agraval1, Liya Dreval1,2, Anna Vodopyanova1

pagraval68@gmail.com

1Donbas State Engineering Academy, Ukraine

2MSI, Materials Science International Services GmbH, Stuttgart, Germany

Metallic glasses have attracted much attention from materials science researchers. At the same time, finding new compositions of multicomponent metallic glasses by trial-and-error method requires significant costs and efforts associated with conducting experimental re- search. Therefore, to search for new promising compounds, scientific forecasting methods should be used, among which the thermodynamic approach occupies an important place. In this work, the results of calculating the temperature-composition dependence of the thermodynamic mixing functions of equilibrium and supercooled Cu–Co–Ni–Ti–Zr and Cu– Co–Ni–Ti–Hf liquid alloys are presented, and the chemical short-range ordering in them, are discussed. The obtained results were used to predict the composition regions of glass formation. A database containing interaction parameters for boundary binary and ternary systems was used for calculations of thermodynamic properties of multicomponent liquid alloys. The phenomenological Associate Solution Model (ASM) is used to describe the thermodynamic mixing functions of glass-forming liquid alloys. The degree of chemical short-range ordering in liquid alloys is estimated in the framework of ASM as the total mole fraction of associates in the solution. Glass-forming composition regions are pre- dicted using the empirical rule, according to which amorphization by quenching proceeds successfully for melts in which the total molar fraction of associates exceeds 0.3 at the glass transition temperature. The analysis of predicted composition regions of amorphiza- tion of the melts of the Cu–Co–Ni–Ti–Zr and Cu–Co–Ni–Ti–Hf systems allows us to specify the certain total concentration of metals, which are donors (Ti, Zr, Hf – IVB metals) and acceptors (Co, Ni, Cu – Late Transition Metals, LTM) of electrons in the melt. The com- position of rapidly quenched metallic glasses of the Cu–Co–Ni–Ti–Zr and Cu–Co–Ni–Ti–Hf systems must be fulfilled the conditions ΣxLTM > 0.25 and ΣxIVB > 0.28.

Acknowledgments


This work was supported by the Ministry of Education and Science of Ukraine under the grant 0122U000970.



The impact of high-voltage electric discharge treatment of the initial powder mixture on the properties of the composites of the Cu – Al – C and Ti – Al – C systems


Olha Syzonenko, Andrii Torpakov, Mykola Prystash, Yevhen Lypian

torpakov@gmail.com


Institute of Pulse Processes and Technologies of NAS of Ukraine


The development of new materials by high energy treatment is an important task of modern materials science. Materials consolidated using the spark plasma sintering (SPS) method have 1.5–2 times higher physical and mechanical properties than those obtained by con- ventional metallurgical methods [1]. High-voltage electric discharge (HVED) preparation of powders allows obtaining a highly dispersed initial powder mixtures, saturated with high-modulus fillers. After consolidation, the materials of the Сu – Al – С system can be used for contacts of electric vehicles, and consolidated composites of the Ti – Al – C system have prospects for use as tool materials. The goal of this work is to study the relationship between the processes of high-voltage electric discharge treatment of the initial powders and the properties of composites of the Сu – Al – С and Ti – Al – C systems. The studies were performed by the variations in the working medium, the type of electrode system, the amplitude of the current, the rate of current growth, and the amount of energy. Dispersity and phase composition were determined for powder mixtures before and after treatment. For consolidated materials, hardness, specific electrical resistance, and wear resistance were studied. After HVED treatment of a powder mixture with an initial composition of 87.5% Al + 12.5% Cu, the average size decreases from 15 μm to 6 μm, while CuAl2 and Al4C3 are formed. For the 85% Ti + 15% Al powder mixture, a decrease in the average size from 20 μm to 6.2 μm was achieved, and up to 20% of TiC is formed. For metal-matrix composites (MMC) of Сu – Al – С system, the hardness reaches 600 MPa, the specific elec- trical resistance is 0.03 Ω ·mm2/m, the weight loss during wear is 0.12 g per 5 km way. For MMC, consolidated from powders with an initial composition of 85% Ti + 15% Al, the hardness reaches 4 GPa, the specific electrical resistance is 0.02 Ω·mm2/m, the weight loss during wear does not exceed 0.04 g per 5 km of way.

Acknowledgments


Work was performed with partial financial support from Research Council of Lithuania and Ministry of Educa- tion and Science of Ukraine. Authors would like to express gratitude to the Armed Forces of Ukraine for their bravery.

References


1. O. Guillon, J. Gonzalez-Julian, B. Dargatz, T.Kessel, G. Schierning, J.Räthel, M. Herrmann, Field-Assisted Sin- tering Technology/Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments. Adv. Eng. Mater., 2014. Vol. 16. P. 830-849. https://doi.org/10.1002/adem.201300409



Development of oxidation resistant refractory high entropy alloys within the system Ta-Mo-Cr-Ti-Al


Bronislava Gorr1, Steven Schellert2, Bjorn Schäfer1, Hans-Jürgen Christ2, Stephan Laube3,

Alexander Kauffmann3, Martin Heilmaier3

bronislava.gorr@kit.edu

1Institute for Applied Materials – Applied Materials Physics (IAM-AWP), Karlsruhe Institute of Tech- nology (KIT), Germany

2Institute of Materials Science, University of Siegen, Germany

3Institute for Applied Materials – Materials Science and Engineering (IAM-WK), Karlsruhe Institute of Technology (KIT), Germany

Refractory High Entropy Alloys (RHEA) are considered novel promising high temperature materials for structural applications at ultra-high temperatures primarily due to their at- tractive mechanical properties. By contrast, the oxidation behavior of RHEA has raised concern owing to pest oxidation, significant weight changes, scale spallation or even com- plete oxidation at elevated temperatures. In this contribution, results on high temperature oxidation behavior of RHEA within the alloy system Ta-Mo-Cr-Ti-Al will be presented. The isothermal oxidation kinetics of alloys was continuously recorded in thermogravimetric de- vices. The oxidation experiments were performed in laboratory air in wide temperature range from 500°C to 1500°C. The crystal structures of corrosion products were analyzed using X-ray diffraction. The morphology of oxides scales and internal precipitates was characterized applying scanning electron microscopy in conjunction with energy disper- sive X-ray spectroscopy. The high-resolution images of the oxide layers were generated in transmission electron microscope. In order to identify the oxidation states, electron energy-loss spectroscopy was utulized in combination with scanning transmission elec- tron microscopy. The experimental results show that the equiatomic alloy Ta-Mo-Cr-Ti-Al exhibits very high oxidation resistant despite the high amount of refractory metals. It was found that the superior oxidation behavior of this alloy is attributed to formation of the rutile-type oxide (Cr,Ta,Ti)O2. The studies on oxidation mechanism of alloys in the system Ta-Mo-Cr-Ti-Al revealed that the growth of this oxide is governed by the inward diffusion of oxygen via oxygen vacancies. A pronounced zone of internal corrosion was, however, observed underneath the oxide scale indicating the notable inward diffusion of oxygen and nitrogen. Due to additions of higher valency metals, e.g. W, the thickness of the zone of internal corrosion was successfully reduced. This experimental finding confirmed the hy- pothesis that the doping of higher valency cations of n-type oxides leads to decrease in the oxygen vacancy concentration. This study showed that while many RHEA indeed suffer from poor oxidation resistance, some RHEA, e.g. the equiatomic Ta-Mo-Cr-Ti-Al alloy, ex- hibit very good protectiveness which is attributed to the formation of rarely encountered Ta-Cr-Ti-based complex oxides which possess high thermodynamic stability and low growth rates.



The influence of physicochemical surface treatment of on the content and composition of inclusions and impurities in synthetic diamonds


Halyna Ilnytska, Valerii Lavrinenko, Olga Loginova, Serhii Starik, Volodymyr Smokvyna, Iryna Zaitseva, Viktoriia Tymoshenko, Liudmyla Kotynska, Viktor Bilorusets, Vladislav Venikov

gil-ism@ukr.net


  1. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


    The purpose of the work was to conduct research to determine the content and compo- sition of intracrystalline inclusions and impurities in synthetic diamond powders used in grinding production. The research was conducted on diamond grinding powders of the AC20 (according to regulatory documents of Ukraine) grade with a grain size of 125/100, obtained in the Ni-Mn-C system, before and after their thermochemical treatment in an al- kaline melt1. Physico-mechanical characteristics were determined: compressive strength; the specific magnetic susceptibility. The total content of inclusions and impurities was determined in the form of unburned residue, obtained after long-term high-temperature treatment to a constant mass. The surface condition, total content, and elemental compo- sition of the original diamond grinding powders and unburned residues before and after thermochemical treatment were determined by the SEM and X-ray spectral microanalysis (processing in an alkaline melt at a temperature not exceeding 600°C). It is shown that their strength is slightly reduced as a result of the thermochemical treatment of the sur- face of diamond grinding powders. Due to the dissolution of a certain part of inclusions and impurities, there is a decrease in the quantitative content of the non-combustible residue by 2 times and a weakening of the magnetic properties by approximately 1.4 times. The total content of inclusions and impurities in diamond powders after their thermochemical treatment decreases by approximately 5wt.%, and the content of carbon solvent alloy ele- ments (Mn+Ni) - by 6wt.%. Additional chemical elements (Mg, K, Ca, Fe) were detected in X-ray spectra microanalysis from the surface of diamonds after their thermochemical treatment, which were not present in the composition of diamonds before treatment. The total quantity and elemental composition of unburnt residues of grinding powders before and after thermochemical treatment decreases by 2.4 times, and the content of carbon solvent alloy elements (Mn+Ni) in them by 1.7 times.

    References


    1. Prikha T.O., Ilnytska G.D., Loginova O.B., Tkach V.M., Smokvyna V.V., Zaitseva I.M., Zakora A.P. Influence of Heat Treatment on the Mechanical Characterictics of Diamond Powders. Powder Metallurgy and Metal Ceramics, 2022. V.60. P. 567-575.



Research on the formation of strength characteristics of synthetic diamond powders


Nonna Oliinyk, Halyna Ilnytska, Galyna Bazaliy

oleynik_nonna@ukr.net


V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


The physical and mechanical properties of the diamond powders, in particular the strength and uniformity of the strength of the powder, primarily affect the efficiency of the abrasive tool. The purpose of the work is to study the formation of powder strength characteristics under the influence of powder flotation separation with preliminary surface activation by iron ions in an ultrasonic field in a liquid. To study the formation of the strength character- istics of powders obtained by flotation separation, powder brand AC 20 with a grain size of 100/80 of the Ni-Mn-C system was chosen. The samples for the study were made by suc- cessive two-stage flotation separation into foam and chamber with preliminary activation of the surface of the powder particles with iron ions in the ultrasonic field in the liquid. The strength characteristics of the products, in particular, the strength index under static compression were studied according to the methods of regulatory documents of Ukraine [1]. . It has been established that the application of surface preparation of AC 20 powder with a grain size of 100/80 and flotation separation leads to the possibility of obtaining powders with a strength index under static compression at the level of 17.9-12.3 N, which coincides with the strength interval of the original powder. The homogeneity in strength and the amount of the obtained powders compared to the original powder (taken as 100%) are: foam product 1 - 166% (quantity - 38.5%), foam product 2 - 100% (quantity - 34.6%), chamber product - 66.6% (quantity - 26.9%). Thus, the application of surface activation of powder particles by iron ions in an ultrasonic field in a liquid and flotation separation allows to obtain a powder with increased uniformity in strength (by 66.6%) of its quantity of 38.5% relative to the original powder.

References


1. G.A. Petasyuk, H.D. Ilnytska, G.A. Bazalii, N.O. Oliinyk, Yu.V. Syrota, Flotation Separation as a Method of Improving the Uniformity of Synthetic Diamond Powders by Their Morphometric Characteristics, Grain Shape, and Grain Composition, Journal of Superhard Materials, 2024. Vol. 46. No. 1. pp. 65–75.



Thermo-kinetics of decomposition to AlN sub-micron powders of vacuum-aluminothermic origin


Viktor Garbuz, Vera Sydorenchuk, Lyudmila Kuzmenko, Tatyana Silinska, Tatyana Khomko,

Valery Muratov, Olga Romanenko, Larisa Romanova

wpetrowa@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The synthesis of AlN/B₁₂Al=3:1 (wt.) powder took place as a result of topological exother- mic vacuum reactions of Al-thermic in the “BN-Al” system according to the conditions [1]. Dark gray submicron AlN powder was extracted by selective decomposition of B₁₂Al with HNO₃:H₂O=1:10 solution. The equipment and technique for measuring the mass fraction or degree of nitrogen extraction (w N₂ or q N₂) by the method of pulse-reduction extraction with carbon by gas chromatography in a helium flow at 1000-4000 K met the requirements of regulatory documents [2].The experimental procedure and calculations were carried out accordingly [3]. Reliable experimental data under equilibrium conditions of reactions of high-temperature dissociation of AlN-micro powders without the participation of carbon and with the formation of Al₄C₃ are given in the monograph [4]. The values of the standard heat content of the reactions were ΔH⁰298K AlN→Al+0.5N₂ = 323 kJ/mol and ΔH⁰298K AlN+0.75С→0.25Al₄С₃+0.5N₂ = 277 kJ/mol, respectively.The obtained average results of measurements in the field of pulse heating at temperatures of 2500-3500K were ΔH⁰298K AlN→Al+0.5N₂ = 345 kJ/mol. That is, the dissociation reaction of submicron AlN powder, despite the strikingly different properties of interaction with alkalis and acids, does not differ from the characteristics of thermal decomposition for micro powders without the participation of carbon.

References


1. O. Vasiliev, V. Muratov, T. Duda ,Thermodynamic Analysis of Perspective AlB12Synthesis Reactions from In- dustrially Accessible Oxygen-Free Compounds, PHYSICS AND CHEMISTRY OF SOLID STATE, 2017. V18, № 3. P. 358-364. DOI: 10.15330/pcss.18.3.358-364 358 ISSN 1729-4428 2. Kushchevsky A., Garbuz V., Pavlygo T., Serdyuk G., Metal powders. Methods of identification instead of sour renewal. Part 4. Zagalny instead of sour when extracted by the method of primary extraction, DSTU ISO 4491-4, 2011. Kiev, State Committee for Stan- dardization of Ukraine. 3.V.V. Garbuz, V.A. Petrova, A.R. Kopan, S.K. Avramchuk, L. M. Kuzmenko, T.O. Selinska and T.M. Terentieva, Reduction Extraction Method for Determining the Enthalpies of Decomposition Reactions of Different Boron Nitride Modifications, Powder Metallurgy and Metal Ceramics, 2020. V. 58, No. 9-10. P. 591-598. 4.Danzer K., Tan E., Molch D., Analytics. Systematic review. Moscow: Chemistry, 1981. 228 p.



Input control of the fused magnesia powders for the needs of the energy industry


Viktor Garbuz, Vera Sydorenchuk, Volodymyr Kolomiiets, Ludmila Kuzmenko, Tatiana Silin- ska, Natalia Ulianchych, Larisa Romanova, Olga Romanenko

wpetrowa@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Measurement of the composition of materials by instrumental methods, including refrac- tory ones, from 100% to ppb is described by the formula of relative deviations (RSD) of Horwitz [1]. In the area of the base, the measurement error can be ±4.0%. For impuri- ties at the ppb level, it is ±50-60%. A widely used method of X-ray fluorescence analysis provides measurement of chemical elements, usually starting with Mg. An error in the measurement of the base of the fused magnesium oxide powder can distort the results of the analysis of the impurity content by an order of magnitude. To overcome this problem, two methods of correction of composition measurement results are usually used. It is a set of relevant standards or software that considers the interaction of atoms in the test (based on the data of simple substances). In the absence of these corrective possibilities, a third method is proposed for the first time. It consists in the procedure of reliable mea- surement of the basis, mass fraction of MgO by chemical methods of arbitration analysis. The obtained results made it possible to correct the results of X-rays fluorescence analysis measurements and to confirm the compliance of the composition of batches of molten MgO powder with the relevant regulatory documents TU 1527-082-05802299-2010.

References


1. R. Albert and W. Horwitz, А heuristic derivation of the Horwitz curve, Anal. Chem, 1997. V. 69. P. 789–790



Comparative study of the photocatalytic activity of anatase nanoparticles formed in metatitanic acid and titanium (IV) isopropoxide systems


Olena Lavrynenko, Maksim Zahornyi, Nadiya Tyschenko, Andrey Ragulya, Lesia Pavlenko

alena.lavrynenko@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Anatase particles are widely used to create photocatalytic materials due to their low cost, biosafety, and high efficiency. The synthesis method and the nature of the precursor com- pound are important factors affecting the nanomaterials’ phase and chemical composition, structure, and properties. The purpose of the present work is to compare the photocat- alytic activity of nanosized particles of titanium dioxide obtained in the titanium tetraiso- propoxide (TTIP) and metatitanic acid (MTA) systems. According to XRD data, all the obtained samples correspond to anatase. The samples obtained in MTA systems are char- acterized by a lower degree of crystallinity and differ in the content of S impurity, which is ~0.035% in MTA (1) and ~0.83% in MTA (2), respectively. The CSR of MTA (1) particles is 8 nm, the crystal lattice parameters are a = 0.3765 nm, c = 0.9435 nm, the degree of tetragonality c/a = 2.506, V = 0.134 nm3. The CSR of MTA (2) particles is 11.5 nm, the parameters a = 0.3748 nm, c = 0.9407 nm, c/a = 2.51, V = 0.132 nm3. The CSR of TTIP particles is 9.1 nm, the parameters a = 0.3775 nm, c = 0.9479 nm, c/a = 2.51, V = 0.135 nm3. The values of the point of zero charge of the samples are as follows: MTA (1) = 6.37; MTA (2) = 5.02 and TTIP = 8.8. A comparison of the photocatalytic activity of the particles was carried out by UV-VL spectroscopy. According to the degree of discoloration of the day’s solutions with the initial concentration of 20 mg/dm3 within 60 min, the efficiency series is determined. For Methyl Orange: TTIP 63.5% < MTA (1) 67.9% < MTA (2) 74.4 %. For Orange G: TTIP 28.0% < MTA (1) 95.5% < MTA (2) 99.75 %. For Methylene Blue: MTA (2) 59.0 < MTA (1) 70.2 < TTIP 91.0, and for Rhodamine B: MTA (1) 63.6 < TTIP 69.0%.

The probable cause of this difference can be both the crystal structure of the samples, the presence of sulfur in their composition as active additive, and the surface charge of the anatase particles.

Acknowledgments


Dr O.M. Lavrynenko is supported by the PAUSE program, a national emergency program for scientists and artists in exile, run by the Collège de France.

References


1. Lavrynenko O.M., Zahornyi M.M., Paineau E., Pavlenko O.Yu., Tyschenko N.I., Bykov O.I., Characteristic of TiO 2 &;Ag 0 nanocomposites formed via transformation of metatitanic acid and titanium (IV) isopropoxide, Materials Today: Proceedings, 2022. https://doi.org/10.1016/j.matpr.2022.03.002



Formation of microstructure and optical characteristics of Al₂O₃/YAG:Ce eutectic obtained by HDC method


Yurii Siryk, Oleh Vovk, Leonid Gryn, Viacheslav Baranov, Sergii Nizhankovskyi

sirik@isc.kharkov.ua


State Scientific Institution “Institute for Single Crystals” of National Academy of Sciences of Ukraine

Ce³⁺ doped directionally crystallized Al₂O₃/YAG eutectic composites show promise as fluo- rescent converters for powerful LED and LD white light sources [1]. The mechanical and optical characteristics of these composites depend on the dimensional and morphological parameters of the eutectic microstructure, which are influenced by the crystallization con- ditions and Ce impurity concentration. This work investigates the effect of crystallization rate and Ce concentration on the microstructure parameters of the Al₂O₃/YAG:Ce³⁺ eutec- tic obtained through the horizontal directional crystallization (HDC) method. The results indicate that Al₂O₃/YAG:Ce³⁺ eutectic is a proficient optical medium for light scattering. The shape of the elastic light scattering indicator depends on the sample thickness, the characteristic eutectic distance λₑᵤₜ, and the angle of incidence of the primary beam. The presence of Al₂O₃/YAG:Ce³⁺ eutectic texture with a cellular morphology obtained by direc- tional crystallization causes these effects. It is important to consider these factors during converter manufacturing. The emission spectra of Al₂O₃/YAG:Ce³⁺ eutectic samples ex- hibit a broad emission band resulting from 5d¹ - 4f electronic transitions of the Ce³⁺ ion in the YAG matrix. The radiation intensity of the samples varies along the ingot due to an increase in Ce concentration from the beginning to the end of the ingot. Analysis of the emission peaks revealed that the eutectic morphology can increase the reabsorption of Ce³⁺ ion radiation, resulting in a shift of the luminescence maximum towards the red part of the spectrum. The Al₂O₃/YAG:Ce³⁺ eutectic samples obtained exhibit excellent lighting characteristics, with a luminous efficacy of 142 lm/W, a color rendering index of 72%, a cor- related color temperature of 5120 K, and chromatic coordinates of x-0.3500 and y-0.400. Therefore, we recommend this eutectic as a phosphor for high-power white LEDs.

Acknowledgments


This study was supported by the Ministry of Education and Science of Ukraine, project No. 0123U102743 ”En- suring the development and the investigation of properties of eutectic composites from refractory oxides”.

References


1. Shakhno A, Zorenko T, Witkiewicz-Łukaszek S, Cieszko M, Szczepański Z, Vovk O, Nizhankovskyi S, Siryk Y, Zorenko Y. Ce³⁺ Doped Al₂O₃-YAG Eutectic as an Efficient Light Converter for White LEDs. Materials. 2023; 16(7)



Electrochemical synthesis of ultra-dispersed tungsten powders in molten salts


Serhii Kuleshov1, Olha Medvezhynska1, Inessa Novoselova1, Anatoliy Omel’chuk1, Valerii Bykov2

sergiykuleshov@gmail.com

1V.I. Vernadsky Institute of General and Inorganic Chemistry of the Ukrainian National Academy of Sciences, Ukraine

2V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

The development of energy-efficient and environmentally friendly methods for producing ultrafine tungsten powders and its compounds is an urgent task due to the wide range of their applications. The method of electrochemical reduction of W in molten salts opens up new prospects for obtaining nano-sized tungsten powders and coatings of high purity from various precursors (oxides, sulfides, nitrides) of different morphologies and struc- tures at low temperatures (600–900°C). The article presents the results of electrolysis of tungsten oxygen-containing compounds in molten mixtures of NaCl, KCl, CaCl2 , NaF. Both the traditional reduction of tungsten from precursors (Na2W2O7 , Na3WO3F3) dis- solved in the electrolyte and the deoxidation of the solid WO3 and CaWO4 (Cambridge FFC process) were used. Tungsten powders were obtained by potentiostatic electrolysis (poten- tials range -1 – -3 V) at 750 °C using solid Pt or liquid Ga cathodes and different electrolyte compositions. Detailed information is presented in [1-3]. Depending on the synthesis con- ditions and the electrolytes composition, dispersed (30–50 nm) tungsten powders with a current yield of 45–70% were obtained. It was established that the current efficiency and final product characteristics are affected by both standard electrolysis conditions (temper- ature, cathode potential, current density, etc.) and other conditions: tungsten precursors (the morphology of W obtained from Na2W2O7 is characterized by a well-ordered dendritic shape and from CaWO4 by a fibrous structure with spherical inclusions); cathode material (the use of a liquid Ga cathode improves the processes efficiency) and the mechanism of chemical and electrochemical reactions. Thus, the electrochemical synthesis in molten salts can become an alternative to traditional methods of tungsten obtaining. The opti- mization of the conditions of these processes will make it possible to synthesize of W-Co alloys or powders (coatings) of binary and ternary carbides.

References


1. I. A. Novoselova et al., Electroreduction of ditungstate and carbonate anions in chloride melt, Ukr. Khim. Zh., 2021. V. 87, No. 12. P. 97–108. 2. Bosenko O., Kuleshov S., Bykov V., Omel’chuk A., Electrochemical reduction of tungsten (VI) oxide from a eutectic melt CaCl₂–NaCl under potentiostatic conditions, J. Serb. Chem. Soc., 2022. V. 87, No. 7–8. P. 897–889. 3. I. A. Novoselova et al., Effect of electrochemical synthesis conditions on the composition, structure, and morphology of tungsten carbide powders, Powder Metall. Met. Ceram., 2023. V. 62, No. 3–4. P. 142–152.



Phase transformations in the Al-Fe-Mo system


Iuliia Fartushna1, Maryna Bulanova1, Anatolii Samelyuk1, Victor Vitusevych2

juliefart81@gmail.com

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2ACCESS e.V., Germany

Introduction Fe3Al-based alloys are considered to be potential high-temperature structural materials due to their excellent resistance to thermal corrosion, high-temperature oxida- tion and sulfidation, combined with high strength, low density and comparably low cost. However, they have several disadvantages, such as low ductility at ambient temperatures and insufficient strength above 600°C. The addition of molybdenum increases the yield strength, tensile strength and resistance to wet corrosion [1, 2]. Methods Bulk metals of Al-99.995%, Fe-99.9%, Mo-99.9% were used to produce the ternary alloys. Alloys of 1-3 g were prepared by arc-melting under a purified Ar atmosphere (99.998%) using a non-consumable tungsten electrode on a water-cooled copper hearth. The samples were homogenized at 1450, 1300 and 1200°C during 30-100 h in a resistance furnace SShVL- 0.6.2/16. The annealed alloys were then examined by scanning electron microscopy, elec- tron probe microanalysis, and X-ray diffraction. Results Isothermal sections at 1450, 1300 and 1200°C have been determined experimentally for the first time in the entire range of compositions. The ternary intermetallic compound Al8FeMo3 (τ) with Al3Ti-type struc- ture was observed at all investigated temperatures. It was shown that the (Mo) and (αFe) phases form the continuous solid solution (αFe,Mo) at 1450°C, which decomposes into (Mo) and (αFe) phases with the temperature decreases. The Fe7Mo6 (μ) phase, which in the binary Fe-Mo system is formed in solid state at 1368°C, extends into the ternary system up to 16 and 15 at.% at 1300 and 1200°C, respectively. Addition of Mo stabilizes the Al8Fe5 phase, and at 1300°C a narrow homogeneity region of this phase is present, the solubility of Mo in Al8Fe5 at 1200°C was measured as 14.4 at.%. The ternary Al-Fe-Mo and binary Al-Mo systems are thermodynamically re-modelled. The calculated phase diagrams are in good agreement with the corresponding experimental data.

Acknowledgments


Acknowledgments. The work was supported by the National Research Foundation of Ukraine (project no. 2021.01/0278).

References


[1] Liu Y., Zhang L., Cui S., Li W., Vacuum, 2021, 185, P. 110030. [2] Morris D.G., Munoz-Morris M.A., Chao J., Intermetallics, 2004, 12, P. 821-826.



Corrosion of Ti-xSi alloys in marine water


Victor Talash, Mykola Kuzmenko, Julia Rudenko, Vira Shvets

talash@skif.com.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Titanium alloys of the Ti-xSi dual system with different silicon content are the basis for creating of new complex alloys for various functional purposes such as corrosion-resistant, heat-resistant, high-temperature resistant, wear-resistant, and biocompatible medical al- loys. The Ti-xSi alloys were prepared on the basis of the commercial VT1-0 alloy and Silicon (KR1 grade) by the plasma-arc method in an argon atmosphere. The electrochem- ical studies of the obtained alloys (Ti-1.1Si, Ti-3.6Si, Ti-5.7Si, and Ti-2.5Si-2.5Al) were carried out by the potential-dynamic method in a 3 % NaCl solution, which simulates nat- ural environments, including marine water. It was shown that all these obtained alloys are corrosion-resistant. Ti-5.7Si composition proved to be the most corrosion-resistant among the investigated alloys. Ti-1.1Si composition was relatively less stable, while Ti- 3.6Si composition exhibited corrosion resistance in seawater between the first two. Thus, as the silicon content in Ti-xSi alloys increases, their corrosion resistance increases. The addition of Aluminum in the amount of 2.5 % to the Ti-2.5Si alloy leads to an increase in the corrosion resistance of this composition compared to other investigated alloys in the range from the stationary potential to the beginning of the anodic dissolution process, after which the Ti-2.5Si-2.5Al alloy becomes similar in its corrosion resistance to other studied Ti-xSi compositions.

References


Кузьменко М.М. Вплив пластичного деформування на структуру та механічні властивості сплавів системи Ті-Si //Сучасні проблеми фізичного матеріалознавства – Київ. – 2007. – №16. – С. 118 - 129 Лавренко В.А., Талаш В.Н., Лашнева В.В., Кузьменко Н.Н., Красовский М.А. Экспериментальное моделирование взаимодействия сплава Ti-6 (мас.)



Investigation of anomalous strengthening on the near-surface layer of ADI at the influence of the TRIP effect by durometric methods


Yuriy Podrezov, Mykola Minakov, Alex Golubenko

a.golubenko@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Durometric methods have been used to study the strengthening mechanisms of the surface layer of Austempered Ductile Iron (ADI) during friction [1]. The motivation of the work is to create scientifically based approaches to optimize the composition, structure and manu- facturing conditions of soil tillage machinery. ADI samples (3.44%C; 2.62%Si; 0.024%Cr; 0.54%Cu; 0.71%Ni) with different Mn contents: 0.78% and 0.24%(wt.) in both initial and deformed states was tested. The ADI structure was obtained by austenitizing heating at 900°C for 30min. followed by isothermal quenching in liquid tin at 350°C. The content of austenite and martensite in the initial and post-friction states was determined using X-ray analysis on DRON-3M. Hardness was measured using PMT-3 at a load P=0.2N. Instrumen- tal indentation, recording the load P–indenter displacement h curve, was done using a Micron-GAMMA (P=0.2N). Pop-ins (an increase in the depth of indenter penetration with- out an increase in load) on the P(h) curves of ADI indicate martensitic transformations during indentation. The effect is observed at P~0.1N and h~1.5µm. Microhardness in the initial material and after friction showed that on the wear surface one third of the indents has hardness higher than the max. hardness of the initial sample (~6.5GPa) and corre- sponds to the hardness of martensite (7.5–9.5GPa). X-ray analysis of near-surface layers confirmed the transformation of most residual austenite into martensite. Due to marten- sitic transformation the average hardness after friction increases from 4.9GPa to 6.9GPa. Intensive deformation strengthening of bainitic cast iron occurs due to martensitic transfor- mation induced by plastic deformation in the wear zone–the TRIP effect (Transformation- Induced Plasticity). The proposed research methods enable the analysis of the influence of phase composition and structural state on the effectiveness of strengthening the surface layer of ADI products under the influence of the TRIP effect.

References


1. Y. Podrezov, N. Minakov, B. Shurigin, A. Golubenko, K. Grinkevich, M. Askerov, K. Gogajev, Durometric analysis of hardening of the near-surface layer of ADI during friction at the influence of the TRIP effect, Uspihi materialoznavstva, 2023. No. 7. P. 37-49. (in Ukrainian)



Characteristic features of formation of structure, composition, and properties of films of refractory compounds


Oleksandr Goncharov1,2, Ivan Kolinko2, Andrey Yunda3, Svitlana Goncharova2, Dmytro Shyrokorad4, Gregori Kornich4,5

o.goncharov@mss.sumdu.edu.ua

1Institute of Materials Science, Slovak University of Technology in Bratislava, Slovak Republic

2Sumy State University, Ukraine

3V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine

4National University Zaporizhzhia Polytechnic, Ukraine

5Faculty of Physics and Astronomy (EP3), Universität Würzburg, Germany

Functional coatings of refractory compounds, i.e. transition metal nitrides, carbides and borides, having unique physical and mechanical properties, are widely used in various industries [1,2]. Nanocomposite nanostructured coatings of transition metal nitrides and borides due to their high melting point are usually deposited by ion-plasma and magnetron sputtering methods [3,4]. Research of the formation of structural characteristics, physical and mechanical properties of transition metal nitride and boride films, obtained by RF and DC magnetron sputtering, is carried out in this work. It is shown that optimal energy conditions at the deposition are resulted in the formation of a columnar structure (fibrous) and a growth texture of given films. The growth texture (111) with a crystallite size of 10-12nm is formed for both single component (TiN, HfN, etc.) and multicomponent (Ti–Zr– Si–N) films of transition metal nitrides. At the same time, the hardness of multicomponent films is higher compared with single-component TiN and ZrN films. The corresponding tendency is preserved for high-entropy multicomponent nitride coatings (TiHfZrVNb)N. Also, depending on the deposition conditions, the texture (111) is formed. In this case, the nanohardness increases up to 44,3GPa, that is related to the characteristics of the resulting electronic structure. Transition metal multicomponent and high-entropy (Hf,Ta,V,W,Zr)B2 diboride films are characterized by the formation of a columnar structure, and a growth texture in the (00.1) plane. It is noted that the physical properties of the resulting diboride films are identical. The nanohardness and the elastic modulus are varied within 44–48GPa and 400–500GPa, respectively, for both mono- and multi-component films.

Acknowledgments


This research was funded by the Ministry of Education and Science of Ukraine within the framework of project No. 0122U000776. O.A.G. acknowledges support from Scholarships (project No. 09I03-03-V01-00028, 2023-2026) The work was also “Funded by the EU Next Generation EU through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-03-V01-00066”.

References


[1] A.Goncharov, A. Yunda, I. Kolinko, O. Maksakova // High Temp. Mater. Process., vol. 27, pp. 31–52, 2023. [2] A. D. Pogrebnjak, A.A. Goncharov // Metallofizika i Noveishie Tekhnologii. – 2016. – Vol. 38, №9. – P. 1145- 1166. [3] A. Pogrebnjak, A. Goncharov, A. Yunda, I. Shelest, A. Swic, I. Lebedynskyi // High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes. – 2018. – Vol. 22, № 1. – P. 7-15.


[4] O.A. Goncharov, I.S. Kolinko, G.V. Kornich, O.V, Khomenko, D.V. Shyrokorad // Powder Metallurgy and Metal Ceramics, 62 (5-6), pp. 312-325, 2023.



influenct of time and power of microwave radiation on the heating temperature of composite materials based on silicon carbide


Nadia Davyidchuk, Mykola Gadzyra, Yaroslav Tymoshenko, Mykyta Pinchuk

nadia.davydchuk48@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


. Absorption of microwaves by various materials is accompanied by heating of varying degree [1]. The purpose of this work is to study the dependence of the heating tempera- ture of briquetted SiC powders on the microwave radiation time and power. Study of the influence of time from 1 min. up to 3 min. and power from 350 W to 700 W on the heating temperature of the investigated powder materials was carried out due to the absorption of microwave radiation with a frequency of 2.45 GHz . Six samples of silicon carbide synthe- sized under different conditions were used: 1 – synthesized from electrode graphite and Si; 2 – synthesized from petroleum coke and SiOU+2082; 3 – synthesized from thermally ex- panded graphite (TEG) and Si; 4 –ground ceramics infiltrated TEG by Si at 2000U+00BAС; 5 – synthesized from TEG and Si and purified in HF; 6 – ground reaction-bonded silicon and boron carbide (SiC-BU+2084C-Si). The weak dependence of the heating temperature on the time of microwave action at a power of 350 W for samples 1, 2 and 4 is due to the presence of crystalline silicon in the compositions of synthesized silicon carbide powders. The monotonous increase in the heating temperature of samples 3.5 and 6 from the time of microwave exposure is evidence of their high dielectric properties in a wide tempera- ture range. An increase in temperature over 950U+00BA C during of 3 minutes is a main evidence of cubic modification silicon carbide in the form of a solid solution of carbon in sil- icon carbide. Dissolved carbon in the form of planar carbon clusters with sp3 hybridization of atoms leads to an increase in dielectric properties. The phase composition of sample 6 is characterized by the presence mainly of hexagonal 4H-SiC, as well as crystalline silicon. However, the presence of silicon does not affect microwave absorption. A monotonous increase in temperature up to 750U+00BA C is observed during 3 minutes.

Acknowledgments References

1. Palaith D., Silberglitt R. Microwave joining of ceramics. Am. Ceram. Soc. Bull. – 1989. Vol. 69, № 9. P. 1601–1606.



The influence of silicon oxide, aluminum oxide, silicon nitride and titanium on the formation of a solid solution of carbon in silicon carbide


Yaroslav Tymoshenko, Mykola Gadzyra, Nadiya Davydchuk, Mykyta Pinchuk

y.tymoshenko@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The formation of a solid solution of carbon in silicon carbide occurs due to the partial replacement of silicon positions by carbon atoms, which leads to a decrease in the β-SiC lattice parameter and an increase in the hardness of polycrystals sintered at high pressure, which is 30% higher than the hardness of a SiC single crystal [1]. The objective is to examine how a solid solution of carbon in silicon carbide synthesizes in the interaction of carbon with silicon in the presence of SiO₂, Al₂O₃, Si₃N₄ and Ti. To obtain a composite powder material, petroleum coke and silicon were used as starting components. 30 wt.% of SiO₂, Al₂O₃, Si₃N₄ and Ti powders were added to the powder mixture С–Si. Synthesis of composite powder material were carried out at a temperature of 1200 °C in air during 1 hour. It was established that the interaction of the components in the С–Si system with the addition of SiO₂, Al₂O₃, Si₃N₄ and Ti occurs with the formation of SiC, SiO₂, Si₃N₄, Si₂N₂O, Al₂O₃, SiAlON and TiCN. It was established that the addition of SiO₂ contributes to the formation of a solid solution of carbon in silicon carbide with the lowest lattice parameter 0.4349 nm. It is shown that the presence of Al₂O₃ in the composition of the charge leads to the formation of a silicon carbide structure with a standard value of the lattice parameter 0.4359 nm. It was investigated that the addition of Si₃N₄ to the composition of the charge leads to the formation of a solid solution of carbon in silicon carbide with lattice parameter 0.4351 nm. It was found that the presence of Ti during the synthesis of silicon carbide does not contribute to the formation of a solid solution of carbon in silicon carbide, since its lattice parameter 0.4357 nm is closers to standard value.

References


1. Mykhaylyk O., Gadzira M., Arrangement of C atoms in the SiC–C solid solution, Acta crystallographica, 1999. V.55, No. 3. P.297–305.



High-temperature oxidation of AlB12-Al composite material


Aleksandr Umanskyi1, Valery Muratov1, Vladimir Sheludko1, Tatiana Khomko1, Valery Kremenitsky2, Aleksandra Pertko3, Marina Vasilkovskaya1, Vladimir Povazhnyi3

dep65@ipms.kiev.ua

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2Technical Center of NASU, Ukraine

3V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, Ukraine

The study of high-temperature oxidation is urgent from theoretical and practical points of view [1]. The object of the study is the AlB12-Al composite material consisting of a porous ceramic frame of AlB12 infiltrated with molten Al in a vacuum at a temperature of 1100 °C. The oxidation of samples was studied by TGA and DSC, as well as by holding them for 1 hour in the temperature range from 500 to 1000 °C. The activation energy of oxidation Еа, the pre-exponential factor k0 and the order of the chemical reaction n were calculated by the method of non-isothermal kinetics with software implementation. X-ray analysis of the composites was carried out on a DRON-3M diffractometer in CuKα-filtered radiation. The structure was studied using a JEOL JSM-6490 LV scanning electron microscope. The most characteristic oxidation intervals can be distinguished: at temperatures from 20 to 225

°C there is a sharp increase in weight gain with low activation energy. With a subsequent increase in temperature, the rate of weight gain slows down. In the range of 450-570 °C, a melt of B2O3 is formed, at 655 °C Al melts, which is accompanied by cracking of the oxide layer. In the temperature range of 800-1000 °C, Al borates (Al4B2O9, Al8B2O15, Al18B4O33) are formed, which also prevent oxidation. At T = 646 °C crystallization of the Al melt occurs, as evidenced by the exo-peak at this temperature. Reaction order values range from 0 to 1. Under isothermal heating conditions, starting from 500 °C, there is a gradual weight gain with increasing scale thickness (at T = 1000 °C to 142 μm), with the exception of T = 900 °C, at which the scale thickness is 38.4 μm due to a decrease in the weight gain at this temperature. B2O3 and Al melts fill pores, cracks and smooth the surface, reducing roughness (Ra = 12 nm) and oxidation surface area. Thus, we can conclude that the AlB12-Al composite material is resistant to high-temperature oxidation up to T = 1000 °C.

References


1. A.S. Khanna, Fundamentals of High Temperature Oxidation/Corrosion, High-Temperature Corrosion. Ed. by

A.S. Khanna. – World Scientific, New Jersey, USA, 2016.– PP.1-31.



Synthesis of Composite Powders of the Si3N4–NbN System


Roman Lytvyn, Ihor Poliakov, Iryna Kud, Oleksandr Myslyvchenko, Roman Mediukh, Larysa Krushynska, Ostap Zgalat-Lozynskyy

polykov_igor@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Ceramic composites based on silicon nitride belong to the most promising materials for producing wear-resistant products operated under extreme conditions [1]-[3]. The present work is devoted to the investigation of conditions for preparing Si3N4–20 vol.% NbN highly disperse composite powders by in situ solid-state synthesis from Si3N4–Nb reaction mix- ture and by the traditional method of mechanical mixing of Si3N4 and NbN constituent compounds. The Si3N4–NbN and Si3N4–Nb reaction mixtures were mixed in a Pulver- izette 6 planetary mill. Synthesis products were investigated by the XRD and SEM meth- ods. The particle-size distribution of the composite powders was determined by the laser diffraction method. The behavior of reaction powder mixture of stoichiometric compo- sitions calculated for the synthesis of higher niobium nitride in the temperature range 800–1400 °С in vacuum by the reaction 4Nb + Si3N4 was investigated [2]. Based on the established regularities, we developed a combined two-stage technological synthesis process of Si3N4–NbN powder, including vacuum annealing at 1000 °С and subsequent nitriding at 1300 °С, which enabled us to obtain Si3N4–20 vol.% NbN powder consisting of multiphase agglomerates with a mean size ≤3 µm and a nanodisperse fraction with a mean particle size of 200 nm. For the preparation of Si3N4–20 vol.% NbN composite pow- der by the traditional mechanical mixing method, β-Si3N4 and δ-NbN powders synthesized under laboratory conditions were used. The mean particle size of the obtained composite powder is ≤10 µm. We established advantages of the method of in situ solid-state synthe- sis of Si3N4–NbN powders, which guarantees obtaining fine-grained powder with a mean particle size ≤3 µm and a uniform distribution of nitride phases in a single technological cycle.

References


1. Zgalat-Lozynskyy O., Kud I., Ieremenko L., Krushynska L., Zyatkevych D., Grinkevych K., Myslyvchenko O., Danylenko V., Sokhan S., Ragulya A., Synthesis and spark plasma sintering of Si3N4–ZrN self-healing composites,

  1. Eur. Ceram. Soc., 2022. V. 42, No. 7. P. 3192-3203. 2. Lytvyn R., Kud I., Myslyvchenko O., Medyukh R., Krushynska L., Zgalat-Lozynskyy O. Synthesis of highly disperse NbSi2–Si3N4 and Si3N4–NbN composite powders, Int. J. Appl. Ceram. Technol., 2024. No. Special. P. 1–9. 3. Kud I., Ieremenko L., Krushynska L., Zyatkevych D., Zgalat-Lozynskyy O., Shyrokov O. Synthesis and consolidation of powders based on Si3N4–Zr. In: Fesenko, O., Yatsenko, L. (editors). Nanooptics and photonics, nanochemistry and nanobiotechnology, and their applications. Springer Proceedings in Physics, 2020. V. 247. P. 23–33.



    Effect of heat treatment on the structure and properties of tungsten cathodes produced by pressing


    Larisa Krushynska1, Roman Tkach2, Olexander Yukalchuk2, Olexander Dudnik3

    lkrushynska@gmail.com

    1E.O. Paton Electric Welding Institute, Ukraine

    2State Enterprise “International Center Electron Beam Technologies E.O.Paton Electric Welding In- stitute of NASU”, Ukraine

    3Limited Liability Company “Tungsten”, Ukraine

    In vacuum metallurgy, electron beam guns (EB guns) are widely used, in which tungsten thermal cathodes (W-cathodes) are the source of electrons. The problem of improving technological processes for producing W-cathodes from the point of view of improving the cost/efficiency criterion remains relevant. The purpose of the work is to study the effect of vacuum heat treatment (HT) on the structure and properties of flat W-cathodes obtained by hot pressing tungsten wire blanks [1]. Comparative studies of the structure (by opti- cal and scanning electron microscopy), mechanical (microhardness measurements) and operational properties (during tests in EB guns) have been carried out. The “as delivered” W-cathodes are plates 0.6 mm thick, 3 mm wide and 100 mm long. It was found that the microstructure of the cathodes in the delivered state is elongated grains, the average width is 3…5 µm, the length is 20…40 µm, the microhardness is at the level of 5.4…5.6 GPa. To study the recrystallization process in the W-cathodes, vacuum HT was carried out in the range of 800…1200°C for a duration of 20 to 120 minutes. It has been established that vacuum HT in the range of 800…1150°C does not have a significant effect on the structure and properties of W-cathodes. Starting from 1200°C, a mixed microstructure is formed, which is a mixture of initial and equiaxed recrystallized grains, the number and size of which increases with increasing exposure time at this temperature. Microhard- ness decreases to 4.7…4.9 GPa. It has been established that to improve the performance characteristics of W-cathodes, a mixed structure must be formed in them: up to 10-30% - equiaxed recrystallized grains, and at least the volume of the cathode material must retain the original structure. The optimal HT regime has been determined. The durability of cathodes heat-treated according to this mode is at least 50 hours, which corresponds to the level of durability of the best foreign cathodes.

    References


    1. Dragobetsky V.V., Shapoval O.O. etc. Controlled effects of plastic deformation of product blanks for metallurgy and transport. Monograph. 2017



On the peritectic dissolution of tungsten in liquid Al


Vladyslav Mazur, Tetiana Soloviova

taso-iff@lll.kpi.ua


National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


When manufacturing heat-resistant metal alloys based on the Ti-Al-W system, technologi- cal difficulties arise, which are due to the large difference in the physical properties of the alloy components. The difference in melting temperature causes intense evaporation of the low-melting component (Al) at the temperature of W dissolution in liquid Al in a melt- ing furnace. Thus, to prevent evaporation, ligatures should be made, which will then be introduced during the preparation of the structural alloy. Methods. Microscopic analysis of samples on a light microscope (Jenaphot 2000 by Carl Zeiss) and a scanning electron mi- croscope (SEM 106I by Selmi) and X-ray phase analysis (Rigaku Ultima IV). Main results. It is shown that the atomic dissolution of W in liquid Al is preceded by Rebinder’s enrichment of intergranular boundaries of W with Al, forming an intermediate ε- or ζ- phase and sub- sequent rafting of the W crystal in the liquid phase. Similarly, dendritic crystals of ε- and other intermediate phases that formed during the interaction of W and liquid Al through a cascade of peritectic reactions are dissolved. Conclusions. 1.The direct dissolution of W in liquid Al at1300 °C is either absent or marginally small. 2.The reaction between liquid Al and W involves the intense diffusion of Al atoms along the grain boundaries and sub- boundaries. This results in the formation of layers of an intermetallic phase ε (T<1300

°C) or ζ (T>1300 °C). The formation of two interfaces of the intermetallic phase (ε/L and ε/W or ζ /L and ζ /W) leads to diffusion of Al atoms from liquid Al through the intermetallic phase to W. 3.The saturation of the ε-phase with Al at the ε/W interface and the ζ-phase at the ζ /W interface causes them to melt and fragment the W. This fragmentation increases the speed of peritectic melting of W, improves the macroscopic homogeneity of the liga- ture alloy, reduces high-temperature evaporation of Al, and reduces energy costs for the technological process.

References


1. Ouyang Yifang. Mechanical alloying of Al-W binary alloy / Ouyang Yifang, Zhong Xiaping, Wu Weiming. // J. Chinese Nonferrous Metals. - 2019, - 9 (1). – P. 69-72. 2. Phase equilibria and phase transformation / Mazur V.I.

  • Kyiv: Politechnika, 2020. – 120 p. 3.Mazur V.I. On contact melting during peritectic crystallization / Mazur V.I.

    // New materials in metallurgy and mechanical engineering. – 2018. - No. 1. - With. 49-51.



    Solubility of AlN-submicropowders of vacuumaluminothermic origin


    Victor Garbuz, Vera Sydorenchuk, Ludmila Kuzmehko, Tatyana Silinska, Tatyana Khomko,

    Valery Muratov, Larisa Romanova, Olga Romanenko

    wpetrowa@ukr.net


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    AlN powders in a wide range of sizes and purposes have influential applications from func- tional and composite ceramics to film technologies in electronics [1]. Products of topolog- ical vacuum-thermic interaction in the system: “BN-Al” submicron powders of B₁₂Al and AlN were used in the production of dense resistive ceramics.Surprisingly, micron AlN pow- ders were not wetted by boiling sodium hydroxide solution. Vacuum-thermic AlN dissolved so exothermically that it had to be quenched in a water bath with ice. X-ray diffraction studies confirmed the hexagonal structure of wurtzite space group P6₃mc. The average size of AlN crystallites ≈ 40 nm in the field of coherent reflection scattering of individual base planes was established.Solid B₁₂Al↓ was selectively dissolved↑ with HNO₃=1:10 so- lution.The black AlN precipitate (vs. white 100 nm in [1]) was filtered off, washed with 5% citric acid, ethanol, dried (130⁰C), sieved, and packed in an airtight container. We are aware of the nuances of the AlN solubility known in reference books. The results of our comparative experiments are obvious. A reversible Gleiter effect of the spatial tran- sition of a significant number of internal 3D atoms of Al and N to the 2D surface of nano- crystallites is observed. The topology of crystallites of solids is described by mathemati- cal topology.The Poincare-Perelman theorem states that we are in a one-connected three- dimensional manifold without an edge, a homeomorphic three-dimensional sphere on the surface of a four-dimensional sphere. Uni-connectivity means the possibility of compress- ing the surrounding world to the point 0D. The reversible process of the Big Bang occurs due to the compression and expansion of 4D↔3D↔2D↔1D↔0D spaces. It is obvious that in the topology of crystallites of solid bodies, the energies of activation of the reactivity of atoms of spatial transitions will be in the series: Ea 3D˂Ea 2D˂ Ea 1D˂ Ea 0D.

    References


    1. https://www.hwnanoparticles.com/uk/aluminum-nitride-powderaln/



    Input control of the fused magnesia powders for the needs of the energy industry


    Victor Garbuz, Veta Sydorenchuk, Volodymyr Kolomiiets, Lyudmila Kuzmenko, Tatiana Silinska, Nataliia Ulianchych, Larisa Romanova

    wpetrowa@ukr.net


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Measurement of the composition of materials by instrumental methods, including refrac- tory ones, from 100% to ppb is described by the formula of relative deviations (RSD) of Horwitz [1]. In the area of the base, the measurement error can be ±4.0%. For impuri- ties at the ppb level, it is ±50-60%. A widely used method of X-ray fluorescence analysis provides measurement of chemical elements, usually starting with Mg. An error in the measurement of the base of the fused magnesium oxide powder can distort the results of the analysis of the impurity content by an order of magnitude. To overcome this problem, two methods of correction of composition measurement results are usually used. It is a set of relevant standards or software that considers the interaction of atoms in the test (based on the data of simple substances). In the absence of these corrective possibilities, a third method is proposed for the first time. It consists in the procedure of reliable mea- surement of the basis, mass fraction of MgO by chemical methods of arbitration analysis. The obtained results made it possible to correct the results of X-rays fluorescence analysis measurements and to confirm the compliance of the composition of batches of molten MgO powder with the relevant regulatory documents TU 1527-082-05802299-2010

    References


    1. R. Albert and W. Horwitz, А heuristic derivation of the Horwitz curve, Anal. Chem,1997. V. 69. P. 789–790



    Inconel 718 Alloy Products Manufactured Using Metal Injection Molding Approach


    Orest Ivasishin1, Dmytro Savvakin1, Oleksandr Rud1, Vitaly Manzhos2, Yury Torba2

    savva@imp.kiev.ua

    1G.V. Kurdyumov Institute for Metal Physics, Ukraine

    2“Ivchenko-Progress” Design Bureau, Ukraine

    The cost-effective manufacturing of nickel-based parts for high-temperature zones of avia- tion gas turbine engines is practically important task. Present study was dedicated to de- velopment of manufacturing approach for gas turbine blades from Inconel-718 alloy (52.50 Ni–18.50 Fe–19.00 Cr–5.10 Nb–3.00 Mo–0.50 Al–1.01 Ti–0.08 C, wt.%) using powder metal injection molding (MIM). The noted net-shape approach is promising for mass production and provides a significant cost reduction compared to conventional manufacturing tech- nologies (casting, hot deformation, machining). However, the important task is achieve- ment of desirable characteristics of MIM produced material itself and products of it, which requires the adaptation of MIM technology for Inconel 718 aviation parts. The manufac- turing route included blending of Inconel 718 powder with organic binder, forming of net- shape compacts, binder removal stage, sintering of powder compacts in vacuum or under argon atmosphere and final heat treatment. Proper selection of technological parameters and conditions for powder forming, sintering and heat treatment ensures manufacturing finished products with the desired phase composition and microstructure [1], and, hence, physical and mechanical properties. Scanning electron microscopy, X-ray analysis, hard- ness and tensile tests were used to characterize the microstructure, phase composition and mechanical characteristics of final product. Optimization of processing conditions ensured achievement of sufficient characteristics, namely, tensile strength of 900 MPa, elongation 16% and hardness of 372 HV of Inconel 718 blades. Implementation of MIM technology is intended in Ukrainian aviation industry for manufacturing high-temperature nickel-based aviation products with improved cost-efficiency.

    References


    [1] W.M. Tucho, P. Cuvilliera, A. Sjolyst-Kverneland, Vidar Hansen, Mat. Sci.& Eng. A 689 (2017) 220-232.



    Thermodynamic properties of melts of the Bi–La system


    Volodymyr Shevchuk, Valentina Sudavtsova

    1975vla1975@ukr.net


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Alloys and compounds of bismuth with lanthanides (Ln) exhibit thermoelectric, magnetic and other properties. For their scientifically based production, it is necessary to know both their state diagrams and the thermodynamic properties of various phases, including the liquid one, because one of the important stages of the technological processes is the melting of the initial mixtures. Thermodynamic properties of liquid solutions based on Bi of the Bi–La system were studied by the EMF method in a number of works. In this work, for the first time, the partial and integral enthalpies of the formation of melts of the Bi–La system in the entire range of compositions were determined by the method of calorimetry at 1220-1274 K. It was established that ΔHmin= −118±4 kJ/mol falls on the melt with xBi = 0.4, and =−401±23; = −212±8 kJ/mol. It has been established that ours and all known ones, except data [1], agree with each other To confirm the reliability of the obtained data and search for regularities in the thermodynamic characteristics of melts of the Bi–La system, it was considered as a member of the Bi–Ln system series. For this, the enthalpies of formation and Tmelt were analyzed of intermetallics LnBi, as well as ΔHmin of melts, relative differences of molar radii and electronegativities of components of Bi– Ln systems, based on which their dependence on the ordinal number of the lanthanide is constructed. It is shown that all dependences, except for the electronegativity differences of the components, are compatible with each other. This indicates that the thermodynamic properties of all phases of the Bi–Ln systems are determined by the size factor.

    References


    1. Zhang J., Sun Q, Sheng J., Electromotive force study of lanthanum in liquid bismuth, J. Molecular Liquids, 2018., 266. 229-232.



    Corrosion of Ti-xSi alloys in marine water


    Victor Talash, Mykola Kuzmenko, Julia Rudenko, Vira Shvets

    talash@skif.com.ua


    Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


    Titanium alloys of the Ti-xSi double system with different silicon content are the basis for the creation of new complex-alloyed alloys for various functional purposes – corrosion- resistant, heat-resistant, heat-resistant, wear-resistant and biocompatible medical.[1]. Ti- xSi alloys were made on the basis of commercial alloy BT1-0 and silicon grade KR1 by plasma-arc method in an argon atmosphere. Electrochemical studies of the obtained alloys (Ti-1.1Si, Ti-3.6Si, Ti-5.7Si, and Ti-2.5Si-2.5Al) were carried in a 3% NaCl solution that sim- ulates natural environments, marine water in particular [2]. The experiments have shown that all the resulting alloys are corrosion-resistant. The composition of Ti-5.7Si turned out to be the most corrosion-resistant among the studied alloys, the composition of Ti-1.Si was comparatively less stable, and the composition of Ti-3.6Si in terms of its corrosion resistance in seawater occupied a position between the first two. As the silicon content of Ti-xSi alloys increases, their corrosion resistance increases. The addition of aluminum in the amount of 2.5% to the Ti-2.5Si alloy leads to an increase in the corrosion resistance of this composition compared to other studied alloys in the range from the stationary po- tential to the beginning of the anodic dissolution process, after which the Ti-2.5Si-2.5Al alloy becomes similar to other studied Ti-xSi compositions in its corrosion resistance. The carried out studies have shown that the processes of formation of oxides of the component on the surfaces of nanofilms have a decisive role in the growth of corrosion resistance of Ti-xSi alloys.

    References


    1. M.M. Kuz‘menko. Structure and mechanical properties of cast alloys of the Ti–Si system // Materials Science.

  • 2008. – Vol. 44, ,№1. – P. 49–53. 2. V. A. Lavrenko, V.N. Talash, V.V. Lashneva, N.N. Kuz‘menko and M.A. Krasovskii. Interaction of Ti–6 wt.



CVD synthesis and morphology of TiN fibers and films


Peter Sylenko, Oleksii Pokropyvnyi, Denis Andrushchenko, Mykola Yakubiv, Igor Okun,

Yuriy Solonin

apokr@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


TiN, due to its excellent properties, is widly used industry, for example, in the manufacture of cutting tools, for the reinforcement of ceramic, metal and polymer matrices, for the creation of electronic devices, in particular, for obtaining solar energy, energy storage, photocatalysis, as well as as biomedical implants and protective wear-resistant coatings [1]. One of the promising directions of materials science is the creation of fibrous composite materials with ceramic, metal and polymer matrices. For this, continuous, micro- and nanofibers of refractory compounds, such as SiC, Si3N4, BN, TiC, TiN, etc., are mainly used [2,3]. In this work, the peculiarities of the processes of synthesis of films, micro- and nanofibers of TiN by the method of chemical vapor deposition (CVD) are considered. The research was done using titanium tetrachloride (TiCl4) in a mixture of nitrogen and hydrogen gases in a wide temperature range, namely 700-1300 °C. Silicon, steel 3 and titanium plates and Al, Sn, Pb, Ni powders were used as substrates. Study of synthesis products by scanning and transmission electron microscopy. With the above synthesis parameters, coatings were obtained in the form of fibers, films with a regular and island structure, namely in the form of plates, needles and stars. It was proved that depending on the material and temperature of the substrates, TiN films or crystals of different shapes and agglomeration were formed on the refractory or molten surface. During deposition at low temperatures (700-900 °C), films without filamentous crystals were observed. The morphology of these films was with microcracks. At temperatures of 1000-1150 °C, the new morphological structures were lamellar, needle-like, and star-shaped crystals. Micro- and nanofibers were formed at temperatures of 1150-1300 °C. A new way of forming star- shaped crystals is proposed by the method of quantum-chemical modeling [4].

References


1. U Mahajan, M Dhonde, K Sahu, P Ghosh, PM Shirage. Titanium nitride (TiN) as a promising alternative to plasmonic metals: a comprehensive review of synthesis and applications // Mater. Adv. – 2024. – V.5, p.846-895. 2. VP Dorokhovich, VS Kopan’, PM Silenko. Some mechanical properties of silicon carbide fibers // Soviet Powder Metallurgy and Metal Ceramics. – 1984. – V.23, p.52-56. 3. UA Joshi, SH Chung, JS Lee. Low-temperature, solvent-free solid-state synthesis of single-crystalline titanium nitride nanorods with different aspect ratios // Journal of Solid State Chemistry. – 2005. – V.178, p.755-760. 4. PM Sylenko, AV Pokropivny, DI Andrushchenko, YM Solonin. Formation of Silicon Carbide Nanoclusters in the Process of Methyltrichlorosilane Oligomerization

// Theoretical and Experimental Chemistry. – 2022. – V.58, p.336-341.



Synthesis of boron nitride from BCNO


Peter Sylenko, Galyna Oleinyk, Oleksii Pokropyvnyi, Olesya Pylypchuk, Yuriy Solonin

apokr@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Boron nitride is well known as material for sythesis analogous of carbon fullerenes, nan- otubes, and fullerites [1], as well as new phases. Hexagonal boron nitride (h-BN) has a complex of high performance such as high values of chemical stability and thermal con- ductivity, good electrical insulation and and lubricating properties, good ability to absorb neutrons. Due to its properties, h-BN is a multifunctional material, it is used to produce cubic boron nitride (c-BN), as high-temperature lubricants and coatings, when creating ceramic composite materials and the like. The h-BN powder is produced by various meth- ods, one of the most common being the reaction of boric acid and melamine [2]. It was shown [3], that the formation of h-BN from boric acid and melamine occurs in the following sequence: first, the BCNO phase (at 350 °C and above) is formed, and with the synthesis temperature up to 800 °C and above in the BCNO phase also found h-BN. The objective of this work was to study the structure formation of BN with BCNO. The synthesis was carried out in a tubular flow quartz reactor at a temperature of 1200 °C in a stream of nitrogen [4]. The obtained samples were examined by transmission electron microscopy and X-ray phase analysis. The powder is composed of flat nanostructured particles. Particle sizes are 1-1.5 microns, and the sizes of the nanoscale substructure elements contained in them are in the range of 20-50 nm. Moreover, the smallest (20-30 nm) substructure elements have a rounded shape, while the largest ones are mainly polyhedral cut. According to Х- ray phase analysis, the sample consists of a hexagonal graphite-like phase of boron nitride. Analysis of microelectron diffraction patterns (MEGs) obtained from the powder confirms this result. However, a comparison of the features of 002 and 100 diffraction reflections in the form of rings on the MEG suggests that the sample also contains rhombohedral boron nitride.

References


1. VV Pokropivny, VV Skorokhod, AV Kurdyumov, GS Oleinik, TS Bartnitskaya, AV Pokropivny. Boron nitride analogous of fullerenes, nanotubes, and fullerites. // SPIE (Engineered Nanostructural Films and Materials). - 1999. - V.3790, p.213-218. 2. A Lipp, KA Schwetz, K Hunod. Hexagonal Boron Nitride: Fabrication, Properties and Application. // Journal of the European Ceramic Society. - 1989. - V.5, p.3-9. 3. M Örneka, C Hwanga, KM Reddy et al. Formation of BN from BCNO and the development of ordered BN structure: I. Synthesis of BCNO with various chemistries and degrees of crystallinity and reaction mechanism on BN formation. // Ceramics Inter- national. - 2018. - V.44, p.14980-14989. 4. GS Oleynik, AV Kotko, MI Danylenko, PM Sylenko, Ju M Solonin, OF Pylypchuk, AI Danylenko, TI Tomila, OO Bochechka, OI Chernienko, OV Kushch. Structural Transitions in Boron Carboxynitride (BNCO) during High-Pressure High-Temperature (HPHT) Synthesis and Sintering. // Journal of Superhard Materials. - 2022. - V.44, p.151-159.



Modeling of structure of liquid alloys by quasi-force algorithm using experimental X-ray intensity curve


Serhii Lysovenko1, Oleksandr Roik2

lisovenko.s@gmail.com

1V.Bakul Institute for Superhard materials, Ukraine

2Taras Shevchenko National University of Kyiv, Chemical Department, Hetman Pavlo Skoropadskyi Street 12, 01033, Kyiv, Ukraine

An information about local atomic structure formation in liquid alloys is very important to understand the impact of temperature as well as content and nature of the components on the nucleation, crystal growth, and formation of stable and metastable solid phases. The aim of this work was consisted in the development of quasi-force method for simu- lation of liquid alloys using experimental X-ray data. An algorithm was developed and corresponding software was written for building structural models of metal melts based on the experimental intensity curve. In this work, the KSM was modified in such a way that at the input it takes not the structural factor, but the experimental intensity curve. Using the kinematic diffraction theory, it calculates the X-ray intensity curve of the simu- lated cell. Obtains the proportionality factor that allows to compare the experimental and model intensity curves. The algorithm was tested on the X-ray scattering intensity curves in the Ni-Mn system from work [1]. The SCIT computing cluster of Glushkov Institute of Cybernetics was used to provide calculations.

References


[1] Roik, O.O., Lysovenko, S.O., Perevertailo, V.M. et al. X-ray study of melts of the Ni-Mn system, J. Superhard Mater., 2009. V. 31 P. 30–34.



The influence of Cr2AlC max phase additives on the mechanical properties and oxidation capacity of the medium-entropy VNiCo alloy.


Maria Saviak1,2, Angel Vicente Escuder3, Vicente Amigó Borrás3

mari_saviak@ukr.net

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine, Ukraine, Spain

2Instituto de Tecnología de Materiales, Universidad Politécnica de Valencia, Spain, www.upv.es/itm, Ukraine, Spain

3Instituto de Tecnología de Materiales, Universidad Politécnica de Valencia, Spain, www.upv.es/itm

FCC high-entropy alloys (HEA) have significant plasticity, deformation of up to 50% is possible, but their yield strength should be higher. The strength of HEA is due to lattice distortion due to the different sizes of the atoms that make up the alloy. The dimension of the vanadium atom is significantly different from the dimensions of nickel and cobalt, and if vanadium is introduced into their composition, a significant distortion of the lattice while preserving the fcc structure. Equiatomic alloy VNiCo, produced by melting in an induction furnace with subsequent heat treatment, showed a yield strength of 1GPa . This yield point is reached in alloys with a grain size of 2 μm. (An alloy with a grain size of 100 μm shows a yield strength of 450 MPa)[1]. The powder metallurgy method makes it possible to obtain HEA with fine grains. Medium-entropy equiatomic alloy VNiCo was obtained by pressing the initial powders under a pressure of 1000 MPa, followed by sintering of the green parts in a vacuum. Cr2AlC MAX-phase powder was added to the mixture of powders of the alloy in the amount of 0.1, 1, 4 mol.%. Cr2AlC was obtained in a single-phase state using mechanical activation in a planetary mill followed by heat treatment. XRD analysis showed that after sintering, we obtained an alloy with a fcc structure and an average grain size of 50 μm. Porosity after sintering was 15%. The VNiCo alloy showed a yield strength of 800 MPa, a Young’s modulus of 108, and a plasticity of 3%. The addition of 10 at.% iron to the obtained alloy significantly improved the plasticity of the alloy, the UTS was 1500 MPa, but the yield strength decreased to 393 MPa. Additions of Cr2AlC MAX-phases in the amount of 0.1 mol.% no affected the value of the yield strength. In the presence of 4 mol.

% Cr2AlC additives, the yield strength decreased to 620 MPa. The work shows that in the presence of Cr2AlC additives, the resistance of the alloy to oxidation increases

References


[1]. Seok Su Sohn, Alisson Kwiatkowski da Silva, Yuji Ikeda, Fritz Körmann, Wenjun Lu, Won Seok Choi, Baptiste Gault, Dirk Ponge, Jörg Neugebauer, Dierk Raabe, Ultrastrong Medium-Entropy Single-Phase Alloys Designed via Severe Lattice Distortion, Adv.Mater., 2019 . V.31, N,1807142



Structure and physical-mechanical properties of cast heat-resistant FeNiCrCuAl high-entropy alloys


Ruslan Sergiienko1, Roman Serhiiko1, Volodymyr Shcheretskyi1, Anatolii Verkhovliuk1,

Oleksandr Shcheretskyi1, Ievgen Byba2, Oleksandr Roik3

rsruslan17@gmail.com

1Physico-Technological Institute of Metals and Alloys, N. A. S. of Ukraine

2National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

3Taras Shevchenko National University of Kyiv, Ukraine

The crystal lattice of high-entropy alloys (HEAs) undergoes significant deformation, that is why HEAs have high strength, significant wear resistance and corrosion resistance in environments with high chemical activity [1]. This work was aimed at creating new heat- resistant high-entropy alloys, based on inexpensive elements and prepared from common master-alloys, studying their phase composition and structure, as well as determining their physical-mechanical properties. FeNiCrCuAl alloys do not contain such an expensive ele- ment as cobalt (Co), which is usually present in similar metallic systems. FeNiCrCuAl high-entropy alloys were made from a mixture of pure metals (Cu, Ni, Al), low-carbon ferrochromium (FeCr70C1), stainless steel (GX10CrNiMn-18-9-1) and cast iron (content, wt.%: C = 2.60, Si =1.80, Mn = 1.30, Ni = 17.00, Cr = 2.30, Cu = 3.60, S = 0.05, P =

0.07). The investigated alloys were prepared by lost foam and sand mold casting methods. The phase composition of the as-cast FeNiCrCuAl alloys is represented by three phases: BCC-ordered solid solution of type B2, FCC solid solution and complex carbides (FeCr)₇C₃. Carbides were formed due to the presence of carbon in the charge materials such as cast iron (C = 2.6 wt. %) and stainless steel (C = 0.1 wt. %). A wide number of different melt- ings were performed therefore the chemical composition of the alloys fluctuated and the period of the BCC lattice parameter varied from 2.8859 Å to 2.8983 Å, and the FCC lat- tice parameter was from 3.6406 Å to 3.6666 Å. The microstructural analysis of the optical photographs revealed that the structure of the alloys was heterogeneous and consisted of granular and lamellar dendrites and interdendritic space. The HEAs of the FeNiCrCuAl system are characterized by relatively high hardness and samples suffered brittle failure during tensile tests due to the presence of carbides and BCC phase. The Brinell hardness and tensile strength in the as-cast alloys were in the range of 275 HB to 415 HB and from 300 MPa to 748 MPa, respectively.

Acknowledgments


This study was performed under the project (code: III-33-21-705) funded by the National Academy of Sciences of Ukraine.

References


1. Y.Qiu, S. Thomas, M.A. Gibson, et al., Corrosion of high entropy alloys, npj Mater. Degrad., 2017. V. 1, No.15. P. 1-18.



The effect of preliminary grinding of the charge on the structure and properties of hot-forged heat-resistant alloys of the Nb-Ti-Cr-Al-Mo system


Myroslav Marych, Olena Rokytska, Alex Golubenko

myroslavmv@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The development of alloys based on niobium is a promising direction for the creation of heat-resistant alloys with a low specific gravity. Therefore, the task was set to investigate the possibilities of obtaining the alloy by methods of powder metallurgy, in particular hot forging [1-2]. Ti, Al, Mo, Nb, and Cr powders were used as starting materials. 2 types of powder mixtures were formed: without grinding and with preliminary grinding. Grinding of the charge was carried out in a planetary mill for 15 min.Consolidation of powder blanks by the method of hot forging (HF) was carried out on an arc stator press at a temperature of 1200 °C. The annealing of the samples after HF was carried out in a vacuum electric furnace at a temperature of 1600 °C. As a result of the work, powder polycomponent alloys based on niobium were obtained. The technological operation of preliminary grinding of the charge had a significant impact on the microstructure and properties of the alloys. It was established that preliminary grinding of the charge within 15 min. significantly grinds the elements of the structure after hot forging. Porosity decreases due to a more active surface of the particles after grinding. Imaging in the characteristic rays shows that the elements of the alloy are distributed evenly. This indicates a greater degree of diffusion homogenization of the alloy. Grind the mixture of powders for 15 minutes. brings the compressive strength of the hot-forged material closer to the values of the cast one at temperatures up to 800 °С, even with greater porosity of the former. The yield strength of hot forged alloy of NbTiCrAlMo (with grinding) at 800 °С is about 700 MPa, which is almost 2 times more than that of a similar alloy without grinding. Therefore, the production of NbTiCrAlMo alloys by powder metallurgy methods eliminates the problem of element liquation, and preliminary grinding of the charge significantly increases the strength of the obtained alloys.

References


1. Senkov O. N., Senkova S. V., Miracle D. B. and Woodward C. Mechanical properties of low-density, refractory multi-principal element alloys of the Cr—Nb—Ti—V—Zr system / - Mater. Sci. and Engineering: A. — 2013. —

565. — P. 51—62. 2. Brodnikovskii N.P. Resistance of titanium–chromium and zirconium–chromium alloys to air oxidation / N.P. Brodnikovskii, I.V. Oryshich, N.E. Poryadchenko, T.L. Kuznetsova, // Powder Metallurgy and Metal Ceramics. 2010. 49 (7-8), 454-459.



Development of cubic boron nitride synthesis processes using non-traditional technologies (overview)


Ivan Borymskyi, Oleksandr Borymskyi, Sergey Starik

oleksandrborymskyi@gmail.com


V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


Cubic boron nitride (cBN) powders are widely used for construction and instrumental mate- rials in various fields of science and production. The purpose of this work is to monitor the efficiency of processes for the synthesis of cBN powders using a variety of non-traditional technologies, including mechanically activated reaction mixtures and additional crystal- lization centers (DCC) [1]. It was established that the use of a mechanically activated reac- tion charge allows to increase the degree of conversion of hBN→cBN from 30-50 achieved without activation to 85-90 % (by mass) and to obtain a product that mainly consists of micropowders of a deficient narrow grain size range with an average grain size of 3-4 to 10-14 microns. The possibility of synthesizing lithium bornitride Li3BN2 by mechanical ac- tivation of the initial components is shown and the high efficiency of its use in the synthesis of cBN powders is established. The process of synthesis of mixtures of the Mg3N2–MgО system in the mode of combustion of Mg powder in air was studied and the high efficiency of their manufacture and use as components of the reaction charge in the synthesis of cBN powders was established. It is shown that the grains obtained by crushing compacts based on dense modifications of boron nitride, such as hexanite-A and kyborite, are effective DCC in the synthesis of cBN. It was found that the use of hexanite-A grains with a wurtzite con- tent of about 20% (by mass) in the synthesis of cBN as a DCC leads to the formation of two-layered hexanite-cBN grains, which consist of a polycrystalline inner part (hexanite-A) covered with an outer layer that has grown on it layer with cBN. The effectiveness of using such two-layer hexanite-cBN grains as an abrasive tool material is being investigated.

References


1. A. І. Borimsky, M. V. Novikov, І. A. Borimsky, Method of obtaining cBN, Patent of Ukraine 65367 A, Publ. 15.03.04, Byul. 3.



Synthesis of the Ti3SiC2 MAX-phase by pressureless technique


Alexander Rud1, Inna Kirian1, Andrey Lakhnik1, Yuliya Lepeeva1, Oleksandr Marunyak1, Iryna Vynnychenko1, Mykola Skoryk1, Vitaliy Bevz1, Yuriy Zagorodniy2, Vladimir Trachevski3

rudaldim@gmail.com

1G.V. Kurdyumov Institute for Metal Physics of N.A.S. of Ukraine

2Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

3Technical Center of N.A.S. of Ukraine

Recently, the practical interest of researchers has attracted the MAX phase of Ti3SiC2. This phase is characterized by high electrical and thermal conductivities, low density, high Young’s modulus and fracture toughness. The main disadvantage of existing methods for the synthesis of this MAX phase is the presence of impurity phases such as TiC, SiC, Ti5Si3 or TiSi2. The current investigation represents the results of Ti3SiC2 MAX phase synthesis by pressureless sintering. The Ti, Si, and spectrally pure graphite were used to prepare the powder blend. The homogenization of the mixture was carried out at room temperature for duration of 1 hour using a high-energy laboratory planetary mill (Fritsch Pulverisette P-6). Homogenized powder blends were compacted as cylindrical pellets which was sintered at different temperatures in an argon atmosphere for 3 h. The processes of phase formation during synthesis and the structural parameters of individual phases have been studied by SEM, XRD and NMR spectroscopy. The sample sintered at 1300 ºC from Ti3:Si1.1:C2 mixture contained several phase: Ti3SiC2, TiC, SiC and graphite. The percentage of the Ti3SiC2 estimated by full-profile analysis is only about ~ 33 wt.%. An increase in temper- ature leads to a growth in the content of the phase Ti3SiC2 in the sample. The highest maximum yield of the phase Ti3SiC2 ~ 81 wt.% was achieved for the Ti3:Si1.1:C2 mixture at a temperature of 1385 ºC. In addition, about 19 wt% TiC was also observed in this sam- ple. During the heating of the powder mixture to the synthesis temperature of the MAX phase, partial evaporation of silicon occurs. It results in a significant stoichiometric ratio violation of the elements, which leads to a decrease in the content of the Ti3SiC2 phase in the sample. Increasing the silicon content in the initial mixture to ~ 2 wt.% contributed to the production of the MAX phase with a purity of ~ 95 wt.%.

References


1. I.M. Kirian, A.M. Lakhnik, O.Yu. Khyzhun, I.V. Zagorulko, A.S. Nikolenko, O.D. Rud’, Single-step pressure- less synthesis of the high-purity Ti3AlC2 MAX phase by fast heating, Metallophysics and Advanced Technologies. 45(10) (2023) 1165-1177, https://doi.org/10.15407/mfint.45.10.1165. 2. A. Rud, I. Kirian, Y. Zagorodniy, V. Tra- chevski, M. Skoryk, A. Lakhnik, V. Voynash, Formation of Ti3AlC2 MAX phase in the Ti–Al–C system with B2O3 additive, Open Ceramics (2024), doi: https://doi.org/10.1016/j.oceram.2024.100590.



Powders produced by the method of mechanochemical synthesis for thermal spraying of coatings containing MAX phases


Nataliia Vigilianska, Oleksii Burlachenko, Tetiana Tsymbalista

oleksiibur@gmail.com


E.O. Paton Electric Welding Institute, Ukraine


To produce protective coatings containing MAX phases, methods of thin films deposition such as physical vapour deposition and magnetron sputtering are mainly used [1]. Such coatings are only a few microns thick and do not meet the requirements for operation in extreme conditions. Thermal spraying (TS) makes it possible to form coatings several millimetres thick. This work is dedicated to developing compositions and technology of producing powders using commercially available starting materials for thermal spraying of coatings containing MAX phases. The technology of mechanochemical synthesis (MChS) by processing mixtures of powders of the compositions 60.9TiC+39.1TiAl, 75TiAl-25SiC, 68.5(Ti,Cr)C-31.5Al, 82Cr3C2-18Al (wt.%) in a high-energy planetary ball mill was used to produce powders for TS. The compositions were calculated to form the most promising MAX phases: Ti3SiC2, Ti2AlC, Ti3AlC2 and Cr2AlC. The MChS process was performed in air during 1.5 hours. The produced powders products of MChS have a conglomerate struc- ture with particles size <50 μm. In the powder product of MChS of the TiAl-TiC system, the synthesis of MAX phases Ti3AlC2 and Ti2AlC occurs; in the powder of the TiAl-SiC system, Ti2AlC, Ti3AlC2, and Ti3SiC2 are synthesized; in the powder of the (Ti,Cr)C-Al system, Ti2AlC and Cr2AlC are synthesized; in the powder of the Cr3C2-Al system, Cr2AlC is synthesized. In addition to the MAX phases and the phases of the initial components of powder mixtures, the MChS products also contain phases of Ti3AlC, Ti5Si3 and Cr5Al8. It is preferable to use high velocity thermal spraying methods such as HVOF and cold spraying to preserve MAX phases in coatings. The interaction time with oxygen and the high-temperature jet is reduced, and coatings phase composition corresponds to the phase composition of the sprayed powder. In the case of using plasma spraying methods, the syn- thesis of MAX phases can occur directly during spraying and the formation of the coating layer.

References


1. N.V. Vihilianska, D.V. Filonenko, A.O. Yushchenko, C. Senderowski, J.-C. Grivel, Thermal spraying of coatings, containing Cr2AlC max-phase (Review), The Paton Welding Journal, 2024. No. 3. P. 24-32.



Thermodynamic properties of melts of the Ti-Sb(Ce) and Ti-Sb-Ce systems


Mariya Kobylinska1, Valentina Sudavtsova2, Nataliya Usenko1, Nataliya Podoprygora2,

Michael Ivanov2

sud.materials@ukr.net

1Taras Shevchenko National University of Kyiv, Ukraine

2Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

Stibium alloys with transition metals are promising for the creation of new thermoelectric and refractory materials. In order to obtain them on a scientific basis, it is necessary to know the thermodynamic properties of various phases, especially the liquid phase. The enthalpies of formation of melts of binary systems Ti-Sb(Ce) for the first time were inves- tigated by the method calorimetry at 1600 and 1800 K in the range of compositions 0<xTi

<0.7 and 0<xTi<0.5, respectively. The minimum value of the mixing enthalpy of melts of the Ti–Sb system is –28.1 ± 0.3 kJ/mol at xTi = 0.5, and the first partial mixing enthalpies of Ti and Sb are equal to –90 ± 4 and -93 ±5 kJ/mol. Using these data, we calculated all the thermodynamic properties according to the IAS model. It is shown that the activity of the components exhibit moderate negative deviations from ideal solutions, and ΔGexmin =

–7.6 kJ/mol, ΔSexmin = –13 J/mol/K. Having a complete set of data on the thermodynamic properties of intermetallics and melts of the Sb-Ti system, the liquidus curve of its state diagram was simulated. Melts of the Ce-Ti system at 1800 K in the range of compositions 0≤ xTi ≤0.3 are homogeneous and then delaminate. After extrapolating the established molar enthalpies for Ce melts with Ti, we obtained ∆Нmin = 12 kJ/mol at xTi = 0.8. Alloys of ternary systems are difficult for research, because they require large labor and material costs, and they are also long-lasting. Having studied the enthalpy of formation of melts of binary systems Ti-Sb(Ce) and using the thermochemical properties known from the lit- erature for the Sb-Ce system, similar data were calculated for the melts of the Ti-Sb-Ce system according to the Bonnier-Cabos model. It was established that ΔНmin = –120 ± 3 kJ/mol corresponds to the equiatomic composition of the Ce-Sb subsystem.

References


1. Bondarenko T.P., Sudavtsova B.C., Batalyn G.I., Ulyanov V.I. Enthalpies mixing of liquid Fe-Si-Mn alloys // Izv. Academy of Sciences of the USSR. Metals. – 1984. – No. 3. – S. 81-82.



Thermal stability of powdery CrB2, TiB2 HfB2 and ZrB2


Valentuna Sudavtsova1, Dmytro Mishchenko2, Oleksiy Bogachenko2, Ihor Goncharov2,

Inna Neylo2, Volodymyr Kudin3

sud.materials@ukr.net

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2E.O. Paton Electric Welding Institute, Ukraine

3Taras Shevchenko National University of Kyiv, Ukraine

Powdery metal borides have high hardness, so they can be used as abrasives. Thus, the goal of this study was investigation of oxidation of chrome, titanium, zirconium and hafnium borides on air in the range of temperatures 25–1000°C in non-isothermal conditions using the derivatograph Q-1500 with the heating rates 5 and 10 K/min with simultaneous differential thermal analysis. Powdery CrB2, TiB2 ZrB2, HfB2 of “pure 99% were used. The sizes of the studied powders were determined by granulometric analysis. It turned out that particles with a diameter of 5-10 microns predominate in all powders. The studied powders of compounds interact with atmospheric oxygen in different ways. It is shown that powders TiB2 and ZrB2 begin oxidized at 540, 560°C, and CrB2, HfB2 –at 508, 780°C respectively. From TG curves calculated oxidation degree ().The composition of oxidation products was determined by the X-ray method using the DRON-3 device. Ac- cording to X-ray data, the following oxides are formed: MO2(M=Ti,Zr,Hf), Cr2O3 i B2O3. Using the DTA-curves, calculated the heat effects of oxidation processes. At 1000°C, the oxidation degrees of the studied borides are as follows: CrB2(0,13), TiB2(0,15), HfB2 (0,41), ZrB2(0,81). From the obtained DTA curves, the thermal effects of the studied oxidation processes MB2 were calculated. Proportionality coefficient k between the thermal effect and the peak area under the DTA curve were assessed using similar data obtained from derivatographic studies of KCl and Na2WO4, the melting enthalpies of which are known. Taking into account the degree of transformation of the studied substances, we calculated the heat that was released in the studied processes during the complete oxidation of 1 mole of MB2. These data are qualitatively with those calculated according to Hess’s law.

References


1. Voytovych, R. F. High-temperature oxidation of borides of group IV metals: Oxidation of titanium diboride [Text] / R. F. Voytovych, E. A. Pugach // Powder metallurgy. - 1975. - No. 2. - P. 57-62



Thermodynamic properties of liquid alloys of the Sb-Sc system


Valentina Sudavtsova1, Larysa Romanova1, Michael Ivanov1, Volodymyr Kudin2

sud.materials@ukr.net

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2Taras Shevchenko National University of Kyiv, Ukraine

Enthalpies of alloy formation in the Sb-Sc system have not been previously studied because scandium is refractory metal whereas stibium is extremely volatile. In this study, for the first time, the mixing enthalpies of melts in the Sb-Sc system were determined by the calori- metric method in wide concentration regions at 1413-1423 K. The minimum of the integral enthalpy of mixing is –44.8 ±2.3 kJ/mol is observed near the equiatomic composition. Such significant exothermic effects are explained by the large difference in electronegativities of the components. The limiting partial enthalpies of the components are –125±4 kJ/mol for scandium and –129±9 kJ/mol for stibium. In order to monitor how ΔНmin of liquid alloys and ΔfH of monostibides in the Sb–3d-metal systems change, as well as predict sim- ilar data for unstudied systems, we presented them depending on the serial number of the transition metal. For this purpose, we used the most reliable literature data as well as our data obtained in the present study. The data of ΔНmin of Sс–Sb melts obtained in this work correlate with the similar data for the binary systems Sb–3d-metal. Moreover, they are more exothermic than those for 3d-melts, which can be explained by the elec- tronic structure of 3d metals. It is known that there are 8 electrons on the 3d-orbital of Ni, therefore, when forming alloys with stibium, nickel accepts the outer electrons of the lat- ter, forming a donor-acceptor bond. On the contrary, during the formation of liquid alloys of binary systems Sc(Ti)–Sb, the transition of one (two) electrons from the 3d-orbitals of Sc(Ti) to outer orbitals of Sb probably occurs. Based on the values of ΔНmin of the melts of these systems, it can be concluded that the formation of bondings in liquid alloys of binary systems Sc(Ti)–Sb is energetically more advantageous than in the Ni–Sb one.

References


1. Bondarenko T.P., Sudavtsova B.C., Batalyn G.I., Ulyanov V.I. Enthalpies mixing of liquid Fe-Si-Mn alloys // Izv. Academy of Sciences of the USSR. Metals. – 1984. – No. 3. – S. 81-82.



Calcination of metatitanic acid to nano-TiO₂ anatase


Dmytro Baranovskyi1,2, Valerii Kolesnichenko1,2, Andrey Ragulya1,2

baranovskyi.dmytro@gmail.com

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2NANOTECHCENTER LLC., Ukraine

Titanium dioxide crystallizes in three polymorphic modifications: anatase, rutile, and brookite. While rutile is acknowledged as the most thermodynamically stable polymorph of TiO_{2}, anatase commands considerable attention owing to its photocatalytic prowess. This study is focused on the synthesis of anatase, which finds diverse applications. The chosen method involves the decomposition of metatitanic acid, esteemed for its procedural simplicity and reliability in titanium oxide synthesis. Titanium dioxide was synthesized uti- lizing a multi-section rotary furnace developed by the Frantsevich Institute for Problems of Materials Science, NASU. Adjustment parameters of the powder synthesis process were meticulously balanced to minimize the ingress of powder particles into the air without compromising final product quality. The dependency of TiO_{2} crystallite size, ranging from 9 to 13.5 nm, on gas flow rate from 2.5 to 16.5 l/min was elucidated. Furthermore, varying the reactor’s rotational speed from 4 to 18 rpm yielded crystallite sizes ranging from 13.8 to 9.8 nm. Characterization via X-ray diffraction, scanning electron microscopy, and ASAP confirmed the predominance of anatase (approximately 99%) in the obtained powder, with particle sizes ranging from 20 to 30 nm and a specific surface area of 80-100 m^2/g. The final product underwent comprehensive characterization employing various analytical techniques, including Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis.Assessment of the microclimate and dust levels within the working environment was also conducted. The estimated concen- tration of titanium dioxide in the air during TiO_{2} nanopowder production stages did not surpass the maximum permissible limit, and no exceedance of occupational exposure limits for titanium and OBRV of titanium dioxide nanoparticles was recorded. [1].

Acknowledgments


This work was supported by the EU Horizon 2020 Research and Innovation Programme under Grant Agreement No. 862296 (SABYDOMA—Safety-by-design Of nanoMaterials— From Lab Manufacture to Governance and Com- munication: Progressing Up the TRL Ladder).

References


1. Riabovol V.M., Comparative toxicological and hygienic assessment and prevention of the adverse effects of titanium dioxide nanopowders and titanium dioxide-silver nanocomposite in production conditions.: diss. …PhD in Medicine, specialty 222 Medicine: 22 Healthcare. O.O. Bogomolets National Medical University, Kyiv, 2023., P. 76-90.



Analysing the influence of structure morphology on weld metal properties, searching for relationships through multifractal indices


Olha Shtofel1,2, Viktor Holovko2, Daniil Korolenko2

o.shtof@gmail.com

1National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»

2E.O. Paton Electric Welding Institute, Ukraine

The orientation of the structure has a significant effect on mechanical properties. If the grains are oriented in the longitudinal direction, i.e., when deformed along the crystal- lographic planes, which characterise the direction of grain growth during crystallisation, the ductility, as well as the short-term and long-term strength of the alloy, increase. The orientation of the grains in the direction of maximum stresses eliminates the presence of transverse grain boundaries, so the development of cracks along the boundaries in the lon- gitudinal grain orientation is more difficult than in the transverse or equilibrium structure. The paper shows a solution to the problem of finding the angle of inclination of crystallites, calculating their sizes on the example of a model; the connection with the fractal parameter and mechanical properties of the distribution by angles of misorientation of the real struc- ture. The model contains several objects of an arbitrary elongated shape. The task is to determine the orientation of the grains by finding the angle of inclination of each object to the selected axis. The programme, written in phyton with the use of artificial intelligence, is designed to analyse objects of different geometries in the input image. The results of the work consist of two parts. The first part is the program code corresponding to the theory, and the second part is the analysis of the data obtained and comparison with the existing mechanical properties and fractal dimensions of the components. The programme includes: 1) Converting the image to a black-white scale. 2) Detecting various shapes in the image using a thresholding technique. 3) Calculating properties - the length, width, centroid, orientation and angle. 4) Create data files. Further processing of the data allows you to build distributions of orientation angles on a flat structure, analyse the mechanical characteristics and compare them with the fractal dimension of the images.

References


  1. I. M. Zhuravel, V. M. Maksymovych Quantitative analysis of grain orientation and elongation in metallographic images using Hough transforms, Scientific Bulletin of the National Technical University of Ukraine, 2018, vol. 28, no. 5 2. I.S. Gakh, B.O. Zaderiy, G.V. Zvyagintseva, A.V. Zavdoveev, Y.V. Oliynyk Crystallographic and dimensional characteristics of weld structure elements of single crystals of heat-resistant nickel alloys, Journal of Automatic Welding, 2023, No. 9, pp. 3-10 3. K. A. Yushchenko, B. A. Zadery, I. S. Gakh, A. V. Zviagintseva, O. O. Fomakin, and

    1. V. Zavdoveev, Welding of Single Crystals of Heat-Resistant Nickel Alloys as Innovations of Power Gas Turbines, Metallofiz. Noveishie Tekhnol., 2021, vol. 43, No. 10, pp. 1401-1415



      Innovative family of AlMg(X)Si(Y)Mn casting alloys for industrial applications


      Nick Iefimov, Konstantin Grinkevych, Igor Voskoboynik

      ivvosk@ukr.net


      Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


      The choice of the innovative family of AlMg(X)Si(Y)Mn for the development of high-strength aluminum foundry alloys with increased fluidity has several justified reasons. The wide re- gions of univariant eutectic transformation in innovative family of AlMg(X)Si(Y)Mn casting alloys allow for flexible variation of alloy component ratios while maintaining their phase composition [1]. The structure of alloys in this system morphologically resembles mod- ern foundry alloys, and the nature of phase equilibria allows for a significant increase in magnesium content in the solid solution compared to traditional foundry alloys. Thus, materials can be created that simultaneously utilize all strengthening mechanisms (com- posite, solid solution, and dispersion). Considering the peculiarities of the topology of the phase diagram of innovative family of AlMg(X)Si(Y)Mn casting alloys contributed to the creation of a new high-strength (σB up to 450-500 MPa) aluminum-based casting alloy. In this alloy, the matrix is a solid aluminum solution strengthened by Mn and Cu-containing phases that do not interact with the eutectic and are precipitated during thermal treat- ment. The influence of natural aging on the hardness of Mn and Cu alloyed alloys has been investigated. An increase in the saturation of the solid solution during alloying or an increase in quenching temperature accelerates the processes of forming precipitates that strengthen the matrix, thus the increase in hardness in the first 48 hours after quenching depends on the temperature and composition of the alloys. Subsequent artificial aging proceeds through altered stage decomposition, increasing the hardness of the alloys and, consequently, reducing their ductility and fracture toughness. A heat treatment regimen was developed, including quenching and subsequent two-stage aging.

      Acknowledgments


      This work was partially supported by the Frantsevich Institute for Problems in Materials Science, NAS of Ukraine (“Innovative family of AlMg6Si2Mn casting alloys for transportation applications”).

      References


      1. Legka, T. M., Mika, T., Milman, Y., Korzhova, N. P., Voskoboynik, I. V., and Mordovets, N. M. (2019). Constitution of the Al Corner in the Ternary Al–Ge–Mg Phase Diagram. Powder Metallurgy and Metal Ceramics, 57(11–12), 716–722.



Supercritical fluid synthesis and structure of C96 zeolite-like carbon allotrope


Sergii Maloshtan1, Oleksii Pokropyvnyi2, Anatolii Smolyar2

apokr@ukr.net

1M.P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation of the NAS of Ukraine

2Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

Since the beginning of the 21st century, we have entered the era of carbon allotropes. Among this wide spectrum of carbon structures, only four allotropes of carbon with cubic symmetry are currently known. Two of them are the well-known diamond and fullerite. Others are «cubic graphite» and cubic C8. Their structures were proposed as LTA and SOD carbon zeolites, respectively. Other possible structures are only hypothetical. In this report the structure of «cubic graphite» is reinvestigated based on a new electron diffrac- tion experiment and ab initio calculations of carbon zeolites from an available structure database. Carbon microcrystals associated with the «cubic graphite» phase were synthe- sized using the fluid synthesis method at a pressure of up to 200 MPa and a temperature of 500-700 oС from carbon black as a precursor. According to the results of experiments, methods of experimental electron and X-ray diffractions, as well as ab initio calculations, it is proved that the carbon phase is cubic with lattice parameters ~0.895 nm and space group Im-3m [1]. The crystal structure is proposed as carbon C96 zeolite with KFI topology consisting of 96 carbon atoms per unit cell with sp3 hybridization and sp3/sp2 bond types. This type of zeolite consists of eight 6-6 prisms as secondary building units with T-atoms as individual carbon atoms instead of SiO2 in true zeolites. The hybrid structure is more stable by 0.22 eV per atom. New phase has a density of 2.67 g/cm3 and a high hardness up to 10-20 GPa.

References


1. S.М. Maloshtan, A.V. Pokropivny, A.S. Smolyar, V.O. Kuts, V.O. Barcholenko, A.M. Titenko, M. Czank, W. Dep- meier, Supercritical fluid synthesis and structure of a new cubic C96 phase as carbon KFI zeolite with sp3/sp2 hybridization, Mineral. Journ. (Ukraine), 2024, V.24, No.2, https://doi.org/10.15407/mineraljournal.46.02.000



Modification of basalt fibers to improve operational efficiency in aggressive environments


Iryna Diduk1, Yurii Chuvashov1, Olga Yashchenko1, Nataliya Koshelenko1, Ganna Grytsak2

ididuk2@gmail.com

1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

2SE STC “Basalt-fibre materials” IPM NAS of Ukraine

The use of basalt fibre as a reinforcing element, including in cement-concrete composi- tions, is increasing. However, the surface layer of fibers is dissolved during long-term use in the cement matrix, which is associated with cement hydration. Increasing the corrosion resistance of basalt fibers can be achieved by modifying the fibers by heat treatment. The influence of the temperature and processing time of basalt fibers on the chemical stability of fibers in alkaline and acidic environments is studied. For the experiment, fibers with a surface area of 5000 cm2 were taken and kept in solutions of 2N NaOH and 2N HCl at boiling for 3 hours. Chemical resistance was evaluated by the loss of fibre weight. The fibres were preliminarily subjected to thermal treatment in a muffle furnace in the temper- ature range from 300 to 800 C every 100 C, and the time of treatment was 10, 20, and 30 min at each temperature. The average diameter of the studied fibres was 10-14 µm. The fibres were produced under the same forming parameters on a single-filament laboratory stand. The raw material used was basalt with an acidity modulus of Mk = 4.7 and an initial fibre stability in 2N NaOH of 83.8 % and in 2N HCl of 78.7 %. It has been determined that the maximum increase in alkali resistance is observed at holding temperatures of 400 C and 800 C. The maximum increase in acid resistance is observed during heat treatment at higher temperatures of 600, 700, 800 C and is an increase of 20-25 % from the initial one. With an increase in treatment time, the values in both cases decrease, so the optimal isothermal treatment time does not exceed 10 minutes. In the process of heat treatment of fibres, structural changes occur due to phase transitions of iron oxides Fe2+ to Fe3+, with a change in colour, basalt fibres acquire a browner (reddish) shade of colour. The phase transition is accompanied by the appearance of crystalline phase, which causes an increase in fibre density by 10-20 % [1].

References


1. Diduk I.I., Chuvashov Yu.M., Yashchenko O.M., Gorbachov G.F., Klevtsov V.M., Study of the effect of iron oxides in the composition of rocks and technological parameters of obtaining melts and fiber characteristics Scientific notes [in Ukranian], Lutsk: LDTU, 2007. Issue 20, №2, P.47-50.



Critical assessment of phase equilibria in the B-C-Si ternary system


Kostyantyn Korniyenko

korniyenkok@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Phase relations in the B-C-Si system are of great interest above all because boron, carbon and silicon are the basic elements for the development of technically important refractory ceramics and hard materials. Among the phases taking part in equilibria in this system, SiC and B4C are the most promising materials for use in different fields of technology. The addition of boron to silicon carbide SiC increases its hardness, heat resistance and polishing ability at the same time as retaining the high oxidation resistance. On the other hand, the addition of Si to B4C improves its sintering behavior and mechanical proper- ties. The attention of investigators of the constitution of the ternary B-C-Si system has been concentrated mainly on understanding the sintering mechanisms of SiC with boron in combination with carbon and the sintering of boron carbide with silicon. Attempts of the construction of the phase diagram has been carried out by [1, 2] (partial liquidus surface projection, schematic isothermal sections as well as a series of temperature-composition sections) and by [3, 4] (the SiC-B4C section). However, all the available experimental data reported in literature are quite contradictory and insufficient to produce a clear in- terpretation of the phase relationships in the system. With a view to solving this problem, thermodynamic calculations involving the published experimental data were undertaken by a number of authors, in particular, in [5] but the results obtained are still in need of further experimental verification.

References


1. E. Gugel, R. Kieffer, G. Leimer, P. Ettmayer, Investigation in the Ternary System Boron-Carbon-Silicon, Nat. Bur. Stand. Spec. Pub., Sol. State Chem., Proc. 5th Mater. Res. Symp., 1972. V. 364. P. 505-513. 2. R. Kieffer, E. Gugel, G. Leimer, P. Ettmayer, Untersuhungen im System Bor-Kohlenstoff-Silicium, Berich. Deut. Keram. Gesel., 1972. V. 49, No 2. P. 41-46. 3. D.R. Secrist, Phase Equilibria in the System Boron Carbide-Silicon Carbide, J. Am. Ceram. Soc., 1964. V. 47, No 3. P. 127-130. Doi:10.1111/j.1151-2916.1964.tb14369.x. 4. P.T.B. Shaffer, The SiC phase in the system SiC-B4C-C, Mater. Res. Bull., 1969. V. 4, No 3. P. 213-219. Doi:10.1016/0025-5408(69)90058-

  1. 5. B. Kasper. Phasengleichgewichte im system B-C-N-Si, Thesis, Max-Planck-Institut, Dissertation, Stuttgart, 1996. 225 pp.



    Luminescence and UV up-conversion properties of glasses doped with Pr3+ ions


    Olha Bezkrovna1,2, Radosław Lisiecki1, Bogusław Macalik1, Przemysław J. Dereń1

    onbezkrovnaya@gmail.com

    1Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Poland

    2Institute for Single Crystals, NAS of Ukraine, Ukraine, Poland

    The relevance of the synthesis of materials that emit effectively in the UV region of the spectrum is due to the need to create self-sterilizing surfaces without the use of ultraviolet lamps [1]. Materials and surfaces created on their basis that have the ability to absorb photons of ambient or sunlight and next convert them into photons of the bactericidal range of the spectrum (220-280 nm) can contribute to a constant reduction in the content of adsorbed microbes. Pr3+ ions have an advantage as activator ions for creating such materials, since they effectively luminesce in a wide range of wavelengths, including in the UV-C region (200-280 nm) [2]. Vis-to-UV up-conversion (UC) of Pr3+ ions corresponds to the absorption of blue or violet light (430-490 nm region) through 3 H4 → 3 PJ transitions with followed by the UC of the excitation energy [3]. In addition, Pr3+ ions as an activator can produce greenish-blue or red emission due to its excited energy levels 3 P0 or 1 D2 . We chose a stable glass-based SrO-CaO-MgO-SiO2 for doping of Pr3+ ions. Luminescence in a wide spectral range, absorption, and excitation of luminescence were measured and the luminescence lifetimes were estimated. We obtained up-conversion luminescent radiation in the ultraviolet region in the SCMS: Pr3+ glass upon excitations at 444 nm. The up- converted luminescence spectrum of Pr3+ -doped glass was in the 230-330 UV spectral region with the maximum at 275 nm. Intense luminescence of Pr3+ ions in the glasses studied was also observed in the visible and near-IR regions. It was found that significant non-radiative energy transfer occurs between Pr3+ ions, especially in glasses containing higher concentrations of luminescent ions. Synthesized glasses can be suitable as solid state materials for a variety of photonic applications, including the development of UV self-sterilizing surfaces.

    Acknowledgments


    This work was supported by the National Science Centre, Poland, under grant number DEC-2021/41/B/ST5/03792 entitled: Phosphors for UVC LEDs: Self-Disinfecting Surfaces.

    References


    [1] E. Eadie, W. Hiwar, L. Fletcher, E. Tidswell, P. O’Mahoney, M. Buonanno, D. Welch, C.S. Adamson, D. J. Brenner, C.Noakes and K. Wood, Sci Rep., 2022, 12, 4373. [2] D. Nilova, A. Antuzevics, G. Krieke, G. Doke, I. Pudza and

    1. Kuzmin, J. Lumin., 2023, 263, 120105. [3] E.L. Cates, A.P. Wilkinson and J.-H. Kim, J. Lumin., 2015, 160, 202-209.



      Temperature–Composition Sections of the Hf–Rh–Ir System


      Kostyantyn Korniyenko, Lyudmila Kriklya

      korniyenkok@ukr.net


      Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


      Alloys of the Hf-Rh-Ir system are refractory materials similar to Ni-based superalloys with higher melting temperatures, low values of thermal expansion coefficients, good mechani- cal properties at high temperatures and oxidation resistance. Binary alloys based on HfRh3 or HfIr3 are proposed as thermal barrier coatings, on Hf2Rh — as hydrogen adsorbents. To develop high-temperature functional materials based on the Hf-Rh-Ir alloys, an under- standing of phase equilibria in this system is essential. The alloys of the Hf-Rh-Ir system of 16 compositions are prepared from iodide processed Hf, Rh wire and refined Ir powder (purity of 99.98%, 99.97% and 99.97%, respectively) by arc melting. The alloys are inves- tigated in as-cast and annealed at subsolidus temperatures states by optical microscopy, scanning electron microscopy, electron probe microanalysis, differential thermal analysis, melting points measurements (Pirani-Alterthum technique) and X-ray diffraction. Based on the results of the alloys studies, solidus surface of the Hf-Rh-Ir system [1] as well as liquidus surface, melting diagram and Scheil diagram are represented. Also the vertical temperature-composition sections of the system phase diagram by the ray Ir : Rh = 1 : 1, along the isopleths at 15,0 at.% Ir, 10,0 and 42,5 at.% Rh as well as at 30,0; 33,0 and 62,5 at.% Hf are constructed for the first time. These sections demonstrate characteristic peculiarities of phase equilibria in the system in particular temperature ranges of alloys crystallization and character of phase transformations. So, the vertical section by the ray Ir : Rh = 1 : 1 shows the influence of Hf on the phase equilibria character. It was estab- lished that liquidus and solidus curves of the continuous series of solid solutions between high-temperature modifications of HfRh and HfIr with CsCl-type structure decrease quite steeply (vertical sections by the ray Ir : Rh = 1 : 1 and along the isopleths at 15,0 at.% Ir and 10,0 at.% Rh).

      References


      1. L. Kriklya, K. Korniyenko, V. Petyukh, I. Tikhonova, A. Samelyuk, V. Sobolev, P. Levchenko, Solidus surface of the Hf-Rh-Ir system. J. Phase Equilib. Diffus., 2023. V. 44, No 3. P. 394-407. Doi:10.1007/s11669-023-01046-y.



Influence of time and power of microwave radiation on the heating temperature of composite materials based on silicon carbide


Nadia Davidchuk, Mykola Gadzyra, Yaroslav Tymoshenko, Mykyta Pinchuk

nadia.davydchuk48@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Absorption of microwaves by various materials is accompanied by heating of varying de- gree [1]. The purpose of this work is to study the dependence of the heating temperature of briquetted SiC powders on the microwave radiation time and power. Study of the influ- ence of time from 1 min. up to 3 min. and power from 350 W to 700 W on the heating temperature of the investigated powder materials was carried out due to the absorption of microwave radiation with a frequency of 2.45 GHz . Six samples of silicon carbide synthe- sized under different conditions were used: 1 – synthesized from electrode graphite and Si; 2 – synthesized from petroleum coke and SiO₂; 3 – synthesized from thermally expanded graphite (TEG) and Si; 4 –ground ceramics infiltrated TEG by Si at 2000°С; 5 – synthesized from TEG and Si and purified in HF; 6 – ground reaction-bonded silicon and boron carbide (SiC-B₄C-Si). The weak dependence of the heating temperature on the time of microwave action at a power of 350 W for samples 1, 2 and 4 is due to the presence of crystalline sili- con in the compositions of synthesized silicon carbide powders. The monotonous increase in the heating temperature of samples 3.5 and 6 from the time of microwave exposure is evidence of their high dielectric properties in a wide temperature range. An increase in temperature over 950°C during of 3 minutes is a main evidence of cubic modification sili- con carbide in the form of a solid solution of carbon in silicon carbide. Dissolved carbon in the form of planar carbon clusters with sp3 hybridization of atoms leads to an increase in dielectric properties. The phase composition of sample 6 is characterized by the presence mainly of hexagonal 4H-SiC, as well as crystalline silicon. However, the presence of silicon does not affect microwave absorption. A monotonous increase in temperature up to 750°C is observed during 3 minutes.

References


1. Palaith D., Silberglitt R. Microwave joining of ceramics. Am. Ceram. Soc. Bull. – 1989. Vol. 69, № 9. P. 1601–1606.



The effect of a modifying agent with high catalytic activity on the acceleration of the phthalonitrile monomers polymerization


Eugene Pashchenko, Denys Savchenko, Roman Kurganov, Svitlana Kukharenko

denissavchenko1@ukr.net


V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


For the development of high technologies, it is necessary to develop the synthesis of heat- and heat-resistant binders, which are necessary for obtaining composite materi- als intended for work in extreme conditions. The polymerization acceleration strategy is based on the use of reactions of nitrile groups of phthalonitrile oligomers with hydroxyl- containing aromatic and heterocyclic compounds, namely, diphenylolpropane (bisphenol

A) and short-chain hydroxyl-containing oligoimides. The following reagents used: bisphe- nol A, various solvents and biphenylphthalonitriles (BF) synthesized at Inst.Org.Chem.NAS Ukraine. BF with addition of 5–30% hydroxyl-containing oligoimides or bisphenol A was dissolved at 200 °C for 2 h. The precipitate filtered and dried. The polymerization regime was: T=240–-375 °C for 2–4 h. To analyze structural transformations, Fourier transform in- frared spectroscopy (FTIR), gas chromatography/mass spectrometry was used, reflectance spectra were recorded. Modified oligomeric systems based on synthesized phthalonitrile oligomers and hydroxyl-containing aromatic and heterocyclic compounds were obtained. A large number of intermediate products are formed during curing. This accelerates the conversion of nitrile groups. When the content of the modifier increases, the interaction intensifies. The presence of intermediate reaction products promotes the formation of tri- azine and phthalocyanine rings at lower temperatures and intensifies the formation of more heat-resistant structures. It was established that the polymerization of phthalimides can be accelerated by introducing a modifier with high catalytic activity and a large number of active hydrogen atoms. The triazine and isoindole structures formed in the curing reac- tion allow more nitrile groups to be introduced into the polymerization reaction. The study of their ability to polymerize corresponds to the appropriate technological parameters for obtaining composite materials.



Solubility of AlN-submicropowders of vacuum aluminothermic origin


Victor Garbuz, Vera Sydorenchuk, Lyudmila Kuzmenko, Tatiana Silinska, Tatiana Khomko,

Valeriy Muratov, Larisa Romanova

wpetrowa@ukr.net


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


AlN powders in a wide range of sizes and purposes have influential applications from func- tional and composite ceramics to film technologies in electronics [1]. Products of topo- logical vacuum-thermal interaction in the system: submicron B₁₂Al and AlN “BN-Al” pow- ders are used in the production of dense resistive ceramics. Surprisingly, micron AlN powders did not want to be wetted by boiling 20% NaOH solution. Vacuum-thermal AlN dissolves exothermically. X-ray diffraction studies confirmed the hexagonal structure of the space group of wurtzite P6₃mc. The average size of AlN crystallites was determined to be ≈ 40 nm in the field of coherent reflection scattering. Solid B₁₂Al was selectively dissolved with HNO₃=1:10 solution. The black AlN precipitate (vs. white 100 nm in [1]) was filtered, washed with 5% citric acid, ethanol, dried (130⁰C), sieved and packed in a sealed container. The nuances of solubility of AlN are known in reference books. The re- sults of comparative experiments were obvious. A reversible Gleiter effect of the spatial transition of a significant number of internal 3D atoms of Al and N to the 2D surface of crystallitesnano is observed. The mass fraction of oxygen in powders can be a measure of this process. Peripheral Al-atoms have partially broken chemical bonds. Contact with air causes recombination with oxygen in the presence of water vapor. Bridging bonds of the type (=N˃Al-O(HO)Al˂N=)n are formed by the hydrate-solvate mechanism. According to the data of pulse reduction extraction with carbonin helium flow and gas chromatogra- phy, the mass fraction of oxygen in AlN powders decreases with the growth of crystallites. Plasma chemical samples (up to 10 nm) contain 3.2% (by mass) oxygen. Al-thermal sam- ples (40-50 nm) are oxidized by 1.9% (by mass). In furnace synthesis samples (up to 1µ), oxygen is 0.75% (by mass), respectively.

References


1. https://www.hwnanoparticles.com/uk/aluminum-nitride-powderaln/



Mechanical, structural and acoustic properties of new heat-resistant alloys Inconel® Filler Metal 52 and Inconel® Filler Metal 52MSS in the temperature range of 77-1200K


Yuri Semerenko, Viktor Zoryansky

yuri.semerenko@gmail.com


B.I. Verkin Institute for Low Temperature Physics and Engineering, N.A.S. of Ukraine


Inconel®FM52 [1] and it next generation FM52MSS [2] were developed as welding con- sumables for heat and radiation resistant alloy Inconel®690 [3]. Low levels of Al and Ti in FM52MSS provides “clean” weld deposits that tend to be free of inclusions. Improved wetting and clean welds make FM52MSS ideal for welding in radioactively “hot” repair situations. In this regard, it is appropriate to study the physical and mechanical character- istics of these alloys. The acoustic, mechanical and structural properties of the FM52 and FM52MSS were studied using methods of acoustic spectroscopy, active deformation and electron microscopy in a temperature 77–1200K. In FM52MSS chemical heterogeneity in Nb and Mo is observed (grain boundaries are enriched in Nb and Mo with the release of NbC). In FM52 there is increase in the dislocation density during the transition from the grain volume to the boundary, which leads to a sharp gradient of local internal stresses. The distribution of local internal stresses in FM52MSS is uniform, which can be explained by the redistribution of internal stresses along grain boundaries during the defects diffu- sion to the grain boundaries. The failure of plasticity is observed in FM52, where the value of the relative elongation has reduced values, with a maximum in the temperature 1000- 1200K. This temperature range coincides with the temperature interval of the failure of plasticity during the formation of hot cracks. At the same time, this failure in ductility is not observed in the FM52MSS. The behavior of high temperature background of acoustic absorption in FM52 correlates with the temperature range of failure of the plasticity [4]. As established, the availability of effective pinning centers hindering the dislocation mo- bility creates the preconditions for a uniform distribution of dislocations that leads to the absence of gradients of local stresses that, in turn, provides a high heat resistance and hot cracking resistance of the FM52MSS.

References


1. www.specialmetals.com/divisions/welding-products/tradenames/inconel/fm52.pdf 2. www.specialmetals.com/divisions/welding- products/tradenames/inconel/fm52mss.pdf 3. www.specialmetals.com/documents/Inconel alloy 690.pdf 4. Yu.A.

Semerenko, O.V. Mozgovyj, L.V. Skibina, K.A. Yushchenko, G.V. Zviagintseva, Acoustic Properties of New Alloys Inconel 52 and Inconel 52MSS in the Temperature Range of 77—1200 K, Metallofiz. Noveishie Tekhnol., 2015, V.37, No.12, P.1643-1652



Comparison of the М1(IV)–M2(IV)–{Fe,Co,Ni,Cu} phase diagrams (М – Ti, Zr, Hf)


Anastasiia Storchak, Marina Bulanova

a.storchak@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Phase relations in Zr-Ti-{Fe,Co,Ni,Cu}, Hf-Ti-{Fe,Co,Ni,Cu} and Hf-Zr-{Fe,Co,Ni,Cu} are discussed based on the results of our research [1, 2] and literature data. The common features and peculiarities of the systems are revealed. The main common feature is the formation of Laves phases. In the systems with Ni and Cu they base on ternary compounds, and in systems with Fe and Co these are binary-based phases. Based on generalizations made and crystallographic data, phase relations in unstudied Hf-Zr-{Co,Ni,Cu} systems are predicted. It is shown that the complexity of the topology of phase diagrams decreases in the following order: Zr-Ti-based > Hf-Ti-based > Hf-Zr-based. In each row, the most complex are Ni-containing systems. By “complexity” we mean the number of three-phase regions. It is shown that this correlates with the number of d-electrons, that is natural, since in transition metal systems it is d-electrons that define the thermodynamic stability of the phases.

References


1. A.M. Storchak, T.Y. Velikanova, L.V. Artyukh, A.V. Grytsiv, M.A. Turchanin, P.G. Agraval, V.M. Petuykh, Phase Equilibria and Phase Transformations at High Temperatures in Ternary Alloys of the Ni–Ti–Zr System at 50–100 Ni at.2. A. Storchak, V. Petuykh, V. Sobolev, I. Tikhonova, M. Bulanova, Phase Equilibria in the Zr-Ti-Cu System, JPED, 2023, V. 44, No. 5, P. 608-630.



Charge carrier defect-dopant complexes in ZrO₂ co-doped with yttria and scandia


Oleksandr Vasiliev, Valerii Bekenev, Vladyslav Bilyi, Yehor Brodnikovskyi

o.vasiliev@ipms.kyiv.ua


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Co-doping ZrO₂ with yttria and scandia is an attractive way to produce stabilized cubic zirconia with maximized conductivity and fine-tuned thermal stability for specific applica- tion conditions/temperatures. As co-doping may lead to formation of defects with similar dopant atoms (homogeneous) or with Y and Sc atoms (heterogeneous), which can impact ionic conductivity, the aim of this work was to clarify which configuration is a more prob- able case in the mixed system using DFT modeling. The dopant-vacancy complexes were modeled with oxygen vacancy residing closer to one of the dopant atoms (dipoles) and equidistant to two atoms[1] (tripoles) at 3.2 mol. % and as tripoles with vacancies ar- ranged along the [111] direction in cubic zirconia at 10.3 mol. % of added oxide. The configurations were fully relaxed with Quantum Espresso software package with calcula- tion parameters ensuring energy and atomic forces convergence within 1.0·10⁻⁸ eV and 2.7·10⁻² eV/Å respectively. The total energies of the relaxed configurations were used to analyze their relative stability. The dipole configurations showed instability with respect to tripoles for all cases, with homogeneous yttrium configurations having the smallest energy difference with the more stable tripoles of 3.9 meV/atom and the largest of 20.2 meV/atom for heterogeneous configuration with the vacancy near the yttrium atom; for the scandium case the difference was 13.1 meV/atom. Among the tripoles, heterogeneous case has better stability at low concentrations with mixing energy of -7.8 meV/atom, while homogeneous seem to be more stable at high concentrations (mixing energy is 4.2 meV/atom), suggest- ing a transition at some concentration threshold. As stabilization of cubic zirconia typically requires more than 8 mol. % of dopant, a simple linear dependence of ionic conductivity on the concentration of one of the dopants should be expected in practical co-doped sys- tems.

Acknowledgments


This work was supported by the Ministry of Education and Science of Ukraine, project ”Development of electrolyte with improved operational properties for solid oxide fuel cell application” (0123U102769, under contract RN/22- 2023 dated 05/24/2023)

References


1. Parkes MA, Tompsett DA, d’Avezac M, Offer GJ, Brandon NP, Harrison NM. The atomistic structure of yttria stabilised zirconia at 6.7 mol



Electronic structure of cubic and rhombohedral tantalum carbide phases: DFT calculations and X-ray photoelectron and X-ray emission spectroscopy measurements


Ivan Luzhnyi, Egor Shcherbakov, Tetyana Bystrenko, Oleksiy Bystrenko, Oleg Khyzhun

Luzhnyi92ivan@gmail.com


Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine

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Transition metal (TM) carbides are generally nonstoichiometric compounds crystallized within high-symmetry FCC and HCP structures. Carbides based on refractory metals of the IVb - VIb groups are of great importance for scientists and engineers because of their possibility to form intermediate phases in the region of compounds between MC phases (which crystallize in the FCC structure) and M₂C phases with HCP structure. Such interme- diate carbide phases are superstructures. Unit cells of these superstructures are described in hexagonal or rhombohedral (trigonal) systems and are characterized by large values of hexagonal lattice parameter ratio ( 𝑐h ) [1]. In the present work we study from both experi-

𝑎h

mental and theoretical approaches the electronic structure of cubic TaCₓ phases (x = 0.98

and 0.75) and rhombohedral Ta₄C₃ (C/M=0.74) and Ta₃C₂ (C/M=0.67) phases synthesized following the technique [2]. In particular, we have measured energy distributions of the C 2p- and Ta 5d-electronic states and determined experimentally the valence-band structures employing X-ray emission spectroscopy (XES) and X-ray photoelectron spectroscopy (XPS) measurements, respectively. Furthermore, the present XES and XPS data are verified theo- retically by first-principles calculations of total and partial densities of states that are made using the Quantum Espresso software package. We have achieved good correspondence between the experimental and theoretical data in the present work. The present results indicate that, in the sequence TaC₀.₉₈→TaC₀.₇₅→Ta₄C₃→Ta₃C₂ the main maximum of the XPS valence-band spectra shift toward the Fermi energy. In all studied tantalum carbides, a strong hybridization between Ta 5d- and C 2p-electronic states is detected and the charge transfer occurs from tantalum atoms to carbon atoms.

References


[1] R.K.Chuzhko, S.G.Brailovsky, V.A.Kolyagin, A.A.Gavrish, Poverkhnost’, 7 (1983) 116. [2] O.Y. Khyzhun, E.A. Zhurakovsky, A.K. Sinelnichenko, V.A. Kolyagin, J. Electron Spectroscopy Relat. Phenom. 82 (1996) 179.