8th International Materials Science Conference HighMatTech-2023
October 2-6, 2023 Kyiv, Ukraine
Films and Coatings
Head:
Dr.Sci. Maryna Storozhenko
Scientist at AC2T Austrian Excellence Center for Tribology, Austria
Public Relation Specialist at Frantsevich Ukrainian Materials Research Society, Ukraine
Maryna Storozhenko received PhD (2011) and Dr.Sc. (2019) degrees in Materials Science from Frantsevich Institute for Problems of Materials Science of the National Academy of Science of Ukraine. She has been a Leading Researcher of the Department of Surface Engineering and Protective Coatings at Frantsevich Institute for Problems in Materials Science. Currently she continues her study at the Austrian Excellence Centre for Tribology. She also serves as Public Relations Specialist at Frantsevich Ukrainian Materials Research Society. In 2021 Maryna Storozhenko was awarded a scholarship of the Verkhovna Rada of Ukraine for young Doctors of Sciences. The research of Maryna Storozhenko focuses mainly on the development of metal-ceramic materials and protective coatings with improved wear- and corrosion resistance.
Keynote speaker:
Dr.-Ing. Ewald Badisch
Key Researcher for Functional Surfaces / Scientific Management AC2T research GmbH – Austrian Center of Competence for TribologyWiener Neustadt, Austria
Speech Title: High-performance coatings solving tribological challenges
Research fields of interest are industrial maintenance and wear protection, new technologies (e.g. additive manufacturing), tribological coatings (ranging from µm to mm), tribology under extreme conditions (CO2 corrosion, high temperature, etc). His thesis was dedicated to tribological investigations of tool steels and low-friction coatings. He has ~100 publications and about 2840 citations, h-index = 30 (google scholar)
Speakers:
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Oral Session |
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H3-SM8241 |
Oxide spinel protective coatings for steel interconnects of solid oxide cell stacks Sebastian Molin, Justyna Ignaczak, Omid Ekhlasiosgouei, Piotr Jasiński Politechnika Gdańska, Poland Solid oxide cell (SOC) stacks are highly efficient electrochemical energy converters, which have again gained a considerable attention in the last years. One of the applications of SOC stacks is large scale energy storage. To build long-lasting, stable stacks, all the system components need to be optimized. One of the main degradation sources is connected to the use of steel interconnects (bipolar plates), which undergo high-temperture oxidation, resulting in electrical resistance increase as well as possible Cr-species volatilization. In order to prevent these phenomena, ceramic protective coatings are developed. This work will present an overview of the protective coatings researched at Laboratory of Functional Materials at Gdańsk University of Technology. The work comprises design of novel materials, synthesis of powders, optimization of coating procedures as well as corrosion studies, including real stacks.
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Sebastian Molin |
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H3-VZ1348 |
Effect of boron oxide on operational properties of coatings obtained from germanium oxide and zinc sulfide for IR-optics Viktor Zinchenko1, Igor Magunov1, Olga Mozkova2, Boris Gorshtein2 1O.V. Bogatsky Physico-Chemical Institute of National Academy of Sciences of Ukraine Optical devices require the application of special coatings that increase their resolution, contrast, functionality, etc. The most popular are thin-film coatings that work on the principle of light interference. Materials from which interference coatings are made must meet certain requirements. In the case of metal oxides, this is purity with the formation of defect-free coatings with reproducible properties; for metal sulfides and fluorides, the most important are stoichiometry and the absence of oxide admixtures. Most often, the coating is obtained by thermal evaporation in a vacuum. The starting materials (GeO2 and ZnS) were investigated using traditional method for materials. For the first time, the possibility of practical application of GeO as a material for optics in the IR range has been established. However, its use turned out to be impossible without the addition of Boron oxide, B2O3, which acts as a stabilizer of the valence state of Ge(II). This made it possible to successfully replace the traditional material – SiO in large-sized optical elements. GeO in coatings has the exceptionally high climatic resistance. The addition of B2O3 actually catalyzes the reaction between SiO and GeO2, the only volatile product of which is GeO. In a different way, the B2O3 additive works in the case of metal sulfides and fluorides, in which oxide impurities are bound into complex compounds. This makes it possible to reduce their ability to interact with the materials of the evaporator, and therefore to pollute the coating with reaction products. In turn, this has a positive effect on the optical and operational properties of coatings compared to those produced from traditional, unalloyed materials. Thus, the mechanical strength increases by 5-10 times, which brings the coating to the highest category – to group 0. This applies not only to ZnS itself, but also to materials based on it, for example, CVD-composite of ZnS–Ge composition and others.
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Viktor Zinchenko |
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H3-NI1839 |
Features of the formation of ceramic coatings on titanium alloys by plasma-electrolytic treatment with the addition of hydroxyapatite and diatomite Nataliia Imbirovych1, Krzystof Jan Kurdzydlowski2, Oleksandr Povstyanoy1, Valentyna Tkachuk1 1Lutsk National Technical University, Ukraine This work aims at establishing the relationship between the composition of biocompatible coatings and their properties, synthesized in alkaline electrolytes by plasma electrolytic oxidation (PEO).
For better fusion of implants with bone tissue, the morphology of the implant surface have an important role. Therefore, special attention is paid to the porosity of the surface. Recently, the plasma-electrolytic oxidation (PEO) method has been used to obtain ceramic coatings on titanium alloys, including those containing calcium and phosphorus. The advantage of the method is that the obtained coatings on titanium alloys have a highly porous surface, the open porosity of which is up to 0,75%, which determines the speed of implant implantation due to the penetration of soft tissues into the pores. It is known that silicon promotes the activation of bone tissue regeneration. As a result of modification of oxide ceramics with components of the hydroxide group of hydroxyapatite, diatomite, pyrophosphate and polyphosphate, it is possible to obtain coatings characterized by osteoinductivity, biocompatibility and bioactivity.
It was established that the coatings synthesized in the electrolyte without the addition of hydroxyapatite are characterized by the formation large in size, but less commons craters on the surface.
Experimental studies revealed that the introduction of diatomite into the electrolyte leads to the stabilization of the PEO process, as a result of which no jump-like changes in voltage and current were recorded at the beginning and the end of synthesis. It was found that the surface of coatings obtained in electrolytes containing diatomite is characterized by greater roughness and porosity.
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Nataliia Imbirovych |
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H3-OU1126 |
Influence of Ni content on microstructure and microhardness of nickel-graphite abradable seal coatings produced by plasma spraying Oleksandr Umanskyi1, Oleksiy Kuschev1, Maryna Storozhenko1,2, Iryna Martsenyuk1, Oleksandr Terentiev1, Valery Brazhevskyi3, Ruslan Kostyunyk4, Vitalyi Krasovskyy1, Oleksandr Chernyshov3, Tetyana Mosina1 1Frantsevych Institute for Problems of Material Sciences NAS of Ukraine In order to increase the efficiency of gas turbine engines, it is necessary to reduce the gap between turbine casing and blade tips. To achieve this goal, abradable seal coatings are applied on the inner surface of the casing. During the gas turbine operation, the blade tips cut into the coating, providing minimal clearance. These coatings should have low hardness to reduce the wear of blade tips, good bonding strength to prevent spalling off failure, high enough erosion and oxidation resistance. Due to low hardness, self-lubricating properties, and low cost, graphite is considered a promising component to design abradable coatings. However, the deposition of pure graphite on metal substrates is impossible by thermal spraying technique. That is why it is necessary to introduce a metal binding component to provide a high level of adhesion and cohesion of the graphite-based coating. In this study, the graphite-nickel composite powders were developed to deposit abradable coatings by plasma spraying. The particles of such powders consist of a graphite core coated with a Ni layer, which has high heat resistance and can protect graphite from oxidation during plasma spraying. This study aims to investigate the influence of Ni content on the structure and properties of the Ni-C composite powders and plasma coatings. It is shown that nickel-cladded graphite powder with 75 wt.% Ni content (NPG-75) is promising for the thermal spraying of abradable coatings. In this case the thickness of Ni layer on the graphite particles reaches 6-12 µm, the NPG-75 powder has good flowability. The NPG-75 plasma coatings were deposited onto steel substrate. The composition, structure and properties of the coatings were studied.
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Maryna Storozhenko |
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Poster session Important.session is online-only and include 5 min presentation in the common conference room and 1 hour of discussion in individual rooms (Zoom) |
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H3-VI1708 |
Characterization of the Ti-Zr-Mo-C coatings deposited by magnetron sputtering Volodymyr Ivashchenko1,2, Alexei Onoprienko1, Petro Skrynskyy1, Aleksandr Pogrebnjak3,2, Oleksii Sinelnichenko1, Andrii Kovalchenko1, Olena Olifan1, Oleksandr Marchuk1 1Frantsevich Institute for Problems of Materials Sciences, NAS of Ukraine A combination of the unique properties of transition metal carbides (TMC) makes them very promising as protective and wear-resistant coatings for various tools, in particular, the cutting, drilling, and milling machines. One of possible ways to improve the performance of such coatings is an increase of their constituent elements to form multicomponent solid solutions based on TMC. It is a such an approach that was used in the present investigation.
The Ti-Zr-Mo-C coatings were deposited onto Si (100) substrates by direct current magnetron co-sputtering of the Ti0.5Zr0.25Mo0.25 and graphite targets. All the deposition parameters were fixed, beside of the current supplied to the graphite target (IC) that changed in the range of 150-300 mA. The coatings were characterized by using XRD, XPS, indentation, tribological tests. XPS investigations revealed the following bonds in the coatings: Ti-C, Zr-C, Mo-C and C-C and there were no Ti–Ti, Mo-Mo and Zr–Zr bonds. The XRD and XPS data enabled one to suppose that the deposited films consisted of the (Ti,Zr,Mo)C solid solution crystallites embedded into the amorphous carbon matrix, a-C. The Knoop hardness (HK) is an extremal function of IC with the maximum value of about 35 GPa at IC = 250 mA. This value is higher than HK of the constituent binary TMC and can be assigned to the formation of the solid solutions. For the film deposited at IC = 300 mA the friction coefficient was lowest (0.12). The low value of the friction coefficient of this coating can be explained by the rather high carbon content: the graphite layers that surround the crystallites serve as a solid lubricant.
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Volodymyr Ivashchenko |
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H3-AK1749 |
Sputtering of Fe with addition of Mo or W by nitrogen ions: Monte Carlo simulation Anatoly Kuzmichev, Michailo Melnichenko Igor Sikorsky Kiev Polytechnic Institute, Ukraine The ion sputtering is used for coating deposition. The main its characteristic is the dependence of sputtering coefficient on energy of bombarding ions. Unfortunately, data on such characteristic for nitrogen ions are very limited, although nitriding and deposition of nitride layers are widely used in practice. This characteristic is of particular interest to iron alloys because of their practical importance. The purpose of the work is to estimate the coefficients of sputtering with atomic nitrogen ions for compositions containing Fe and Mo or W. The Monte Carlo calculation for ion energies in the range of 0.1–70 keV was performed using the TRIM code, which gives good agreement with experiment. The amorphous target microstructure was assumed. In the indicated above energy range, the sputtering coefficient S for pure Fe is 0.33…0.46 with the maximum value of 1.2 at ion energy of 2 kV. For the composition Fe+1%Mo, the values of the partial coefficient SFe for Fe are 0.25-0.35 and 0.91 at the same ion energies; for Fe+5%Mo, the values of the coefficient SFe are 0.23…0.31 and 0.91; for Fe+1%W, the values of the SFe coefficient are 0.2…0.28 and 0.76; for Fe+5%W, the values of the SFe coefficient are 0.2…0.29 and 0.75, respectively. It can be seen, the heavier and larger the additives to iron, the more SFe is reduced. The decrease in the coefficient SFe is disproportionately stronger than the increase in the relative concentration of heavy additives, both Mo and W. In the case of 1%Mo additive, the partial coefficient of molybdenum SMo is 0.005...0.006 and 0.01, and for 5%Mo we have SMo = 0.01…0.01 and 0.04, respectively. In the case of 1%W addition, the partial coefficient SW is 0.003…0.004 and 0.01 and for 5%W we have SW = 0.008…0.01 and 0.03, respectively.These features, as it may be assumed, are due to strong scattering of relatively light nitrogen ions and recoil iron atoms by heavy Mo and W atoms within the target.
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Anatoly Kuzmichev |
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H3-AD1227 |
Lifetime Improvement of Contact Brush Units of Automotive Power Machines Andrii Dovhal National Aviation University, Ukraine The automotive electric equipment involves the electric machines (starter, alternator) incorporating the brush unit and hybrid drive vehicles as well. It is the friction joint of conducting copper and graphite brush. Work efficiency and lifetime of these machines strongly depend on the contact quality and general state of this friction joint.
Thus preset objective of this study is research of friction joint of brush unit “copper-graphite” under working current flow and technique of its superficial improvement.
For experimental purposes the samples of М1E electric conductive copper ГОСТ 859-2001 complying with ТУ 1276-003-38279335-2013 were fabricated in dimensions of hole disks 16×6×2,5 mm in order to provide the least friction contact area for experiment acceleration. As the friction couterbody the conventional alternator brush made of graphite ГЭ-1, ГОСТ 7478-75 was used. Copper samples were strengthen by electro-spark alloying on unit ALIER-52 on 6-7 modes by aluminum electrode made of rod aluminum ГОСТ 15176-89.
The coated and uncoated samples were tested on the friction test bench М-22ПВ under “pin-on-shaft” layout. Friction speed was about 1,5-2 m/s that complies the test bench shaft rotation speed about 2000-2400 rpm. In order to simulate the brush unit work the 24 V DC voltage was applied to friction contact and linear wear rate was detected.
So uncoated samples have demonstrated the wear rate of 345,5 micrometers per kilometer, unlike coated samples hat have the wear rate 81,8 micrometers per kilometer what is about 4,26 times improvement of electro erosive wear resistance.
Thus the technique researched is suitable and can be recommended for improvement of brush units of vehicle alternators and starters, DC engines collectors for electric power vehicles, hybrid vehicles and quadracopters as well.
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Andrii Dovhal |
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H3-OB1037 |
Strength and crack resistance structural criteria of composite coatings produced by the method of multi-chamber detonation spraying Volodymyr Korzhyk1, Olena Berdnikova1, Petro Stukhliak2, Olga Kushnarova3, Junjun Zнao1, Ihor Skachkov1 1Scientific Research Institute of Welding Technologies named after E. O. Paton in Zhejiang Province, People’s Republic of China An essential task of modern industry is to increase the reliability and durability of products. One of the prospective ways to increase the products operational durability is the ceramics and cermets powders functional coatings application to the working surfaces by the method of high-speed multi-chamber detonation spraying [1]. The purpose of the given work is to establish the regularities of the influence of structural-phase features in the formed material of functional cermets coatings of metal parts on their strength characteristics and crack resistance, while taking into account structural criteria that will provide the required set of strength and crack resistance properties.
The method for thorough and detailed analysis of the structure features, morphology and distribution of phase particles, their stoichiometric composition, substructure parameters, dislocation density in the coating material obtained with help of multi-chamber detonation spraying has been developed in this work. The research of detonation coating material was performed using transmission electron microscopy (TEM) on a JEM-200CX instrument (by JEOL company) with an accelerating voltage of up to 200 kV.
The prospects of using the method of multi-chamber detonation spraying on various materials (steel, copper, aluminum, titanium) and alloys are shown based on the results of the research. A number of composite coatings made of aluminum and zirconium ceramics; chromium, tungsten carbides have been obtained. It has been established that changes occur in the ratio of the following parameters: microhardness, pore volume fraction, phase composition, distribution of dispersed phases, grain, subgrain, dislocation structures, etc, under different processing modes in the surface layers and a corresponding change in the modes of detonation spraying.
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Olena Berdnikova |
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H3-OG1320 |
Analyzing the methods for electrospark alloying with the use of multi-component special process media Oksana Gaponova1, Viacheslav Tarelnyk2, Nataliia Tarelnyk2, Piotr Kurp3 1Sumy State University, Ukraine The paper presents an analysis of technologies for improving the quality parameters of the surface layers of parts, which were carried out by the method of electrospark alloying (ESA) and by additional saturation of surfaces with alloying elements from special technological environments (STE). The technologies of sulfocementation and sulfoalitization were investigated. Metallographic and hardness tests after sulfocementing by ESA showed that the treated surface consists of layers: "soft", hardened and base metal. As the discharge energy increases, the thickness, microhardness, and integrity of the coating increase. The presence of sulfur in STE promotes the sulphidation process. It is shown that sulfur accumulates in the surface of the metal at a depth of up to 30 μm. This zone is characterized by reduced microhardness. A strengthened layer is formed under this layer, it has an increased carbon content and high microhardness. Three zones can be distinguished on the microstructures: a near-surface, non-continuous loose layer, 10-100 μm thick and a microhardness of 1368-2073 MPa, a "white" hardened layer with a thickness of 20-40 μm and a microhardness of 4094 -5157 MPa, diffusion zone and base metal. As the discharge energy increases, the parameters of the layer increase: thickness, microhardness of the upper and white layers, as well as their integrity. It is showed that the largest amount of sulfur is in the surface layer, which characterizes the layer of reduced microhardness. The diffusion zone of aluminum is 30-80 μm, depending on the energy parameters of the ESA process. The near-surface "soft" layer is enriched with sulfur, strengthened with aluminum. The phase composition of the coatings was investigated. It depends on the energy modes of alloying.
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Oksana Gaponova |
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H3-MG1811 |
The structure of boride diffusion coatings produced on selected grades of structural steels Marek Goral, Kamil Ochał, Barbara Koscielniak, Tadeusz Kubaszek, Kamil Gancarczyk, Andrzej Gradzik, Adrianna Przybyło, Jakub Jopek, Magdalena Mokrzycka, Marcin Drajewicz Rzeszow University of Technology, Poland Problem statement and objective:
The Diffusion boride coatings are characterized by high abrasion resistance, good resistance to corrosion, including high-temperature corrosion. Additionally, boride coatings are not wettable by liquid metals such as zinc or aluminium. In the article the microstructure and phase composition of boride coatings deposited on selected structural steels were described
Methods :
The boride coatings were produced using pack cementation method using commercial EKABOR-2 powder. Boride coatings were deposited on alloyed structural steels grades: C45, S355, 16MnCr5, 18CrNiMo7-6, 34CrAlMo5-10, 42CrMo4, 41CrAlMo7. Cylindrical samples with a diameter of 30 mm and a height of 30 mm were boronized in powder at 1000 oC for 4 hours in an argon atmosphere. The process was carried out in an industrial CVD Bernex BPX 325S device. The microstrucuture was analysed using scanning electron microscope Phenom XL equipped with EDS analyser. The XRD phase analysis was conducted using XTRa diffractometer (ARL). The thickess as well as phase composition was analysed on coatings formed on each grades of steels
Main results and Conclusions
The most of obtained boride coatings were charatherized by single phase structure (Fe2B). The formation of brittle FeB phase was detected on S355 and 16MnCr5 grades steels. The average thickness of the boride coatings exceeded 100 micrometers.
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Marek Goral |
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H3-MS1229 |
Microstructure and wear behavior of plasma sprayed (Ti,Cr)C-Ni composite coatings Maryna Storozhenko1,2, Oleksandr Umanskyi1, Oleksiy Melnyk3, Oleksandr Terentiev1, Tetiana Chevychelova1, Viktor Varchenko1, Oleksandr Koval1, Valeriy Brazhevsky4, Oleksandr Chernyshov4 1Frantsevich Institute for Problems of Materials Science, NAS of Ukraine Thermally sprayed cermet coatings are widely used in many engineering applications to protect against wear and corrosion. (Ti,Cr)C can be applied as starting component to produce wear-resistant coatings. As a solid solution, the (Ti,Cr)C is expected to possess the main advantages of TiC with higher oxidation resistance owing to the formation of Cr2O3. In order to improve the fracture toughness and cohesion of coatings, the metal or alloy powder are introduced as the binder into (Ti,Cr)C-based composite powders.
In the present work, the (Ti,Cr)C-based composite powders with different Ni binder content (18, 25, 33 wt.%) were deposited onto steel substrate by plasma spraying. The aim was to investigate the influence of Ni content on the microstructure, coefficients of friction, and wear rates of plasma sprayed (Ti,Cr)C-Ni coatings, and the wear mechanisms was also discussed. The microstructure and dry sliding wear resistance of the (Ti,Cr)C-Ni coatings were investigated. The (Ti,Cr)C-Ni coatings have a heterogeneous structure composed of (Ti,Cr)C particles and Ni binder. Fracture and partial dissolution of the (Ti,Cr)C particles were found to occur during the plasma spray process. Among all the tested coatings, (Ti,Cr)C-33wt.%Ni coating exhibits lower wear rates and friction coefficients under all conditions. Worn surfaces of the coatings were analyzed using SEM to investigate the wear mechanism. The main wear mechanism of the (Ti,Cr)C-18wt.%Ni is a combination of abrasive wear and delamination phenomena, while the (Ti,Cr)C-25wt.%Ni shows adhesive wear. The (Ti,Cr)C-33wt.%Ni coating exhibits high wear resistance due to the realization of the tribo-oxidation wear mechanism.
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Oleksiy Melnyk |
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H3-AC1300 |
Modeling of gas-discharge processes and formation of diffusion discrete-matrix structure of tube inner surface by ion - plasma nitriding Ihor Smyrnov, Anatolii Kuzmichev, Leonid Tsybulsky, Andrii Chornyi, Volodymyr Lysak National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” The ion-plasma nitriding is used for obtaining diffusion surface layers with high corrosion, wear and crack resistance. This technology is also attractive for forming a promising discrete-matrix structure of the inner surface of steel tubes, but there is a problem of processing in closed space inside the tubes of small diameter and large length. This work is devoted to this problem.
The nitriding of inner tube surface was realized in a coaxial discharge system with the tube as a cathode and the internal electrode as an anode. The anode also was a tube and had side holes through which the working gas (Ar+N2) was admitted into the tube. A pulsed DC power supply provided support for an anomalous glow discharge for heating and ion treatment of the tube inner surface. The COMSOL software was used to simulate the gas processes in the tube cavity.
Modeling of the gas flow has showed its multi-jet nature, in which individual streams were formed by gas flowing out of individual anode holes. The configuration of these streams was influenced by the magnitude of the total working gas flow and the diameter of the anode holes. In places where individual gas streams hit the tube inner surface, a local increase in gas density and nitrogen concentration and, respectively, a variation in the conditions for ion bombardment along the cathode surface were observed. Then it was experimentally found that ion-plasma nitriding of tube inner surfaces with gas providing through the perforated internal anode led to the formation of diffusion coating consisting of areas with different chemical and phase composition, that is the same areas contained the solid phase from iron nitride in a soft matrix of alpha iron, which corresponds to a discrete-matrix coating. Based on the obtained results, it can be assumed that the multi-jet outflow of the working gas through the anode holes makes it possible to format of a discrete-matrix diffusion coating on the inner surface of the steel tube.
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Ihor Smyrnov |
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H3-AK2232 |
Thermophysical properties of lanthanide di-titanates Alla Kopan', Mykola Gorbachuk, Sergij Lakiza, Alina Makudera, Dmytro Korablov Frantsevich Institute for Problems of Materials Science of NASU, Ukraine The rare earth di-titanates are of great interest for materials scientists due to their many technological applications. The Ln2Ti2O7 oxides in the perovskite-like structure have high-temperature piezoelectric and ferroelectric properties. Materials with the pyrochlore structure are attractive as ceramic thermal barrier coatings (TBC), potential solid electrolytes in solid oxide fuel cells and immobilization hosts of actinides in nuclear waste. Some members of the series are also very important for the aeronautical engineering, aerospace and power generation industries. At the same time, many of its properties, especially its thermophysical properties, have not yet been investigated.
The objective of this research is to study the thermophysical properties of Ln2Ti2O7 (Ln = Pr, Nd, Eu, Yb) complex oxides. The rare earth di-titanates samples were characterized by X-ray diffraction. The measurements of thermal conductivity of Ln2Ti2O7 sintered pellets were carried out for the first time in interval 313-673 K in the monotonous heating mode using the dynamic calorimeter method.
The thermal conductivity of the rare earth di-titanates does not show the classical dependence and reaches an almost temperature-independent value above ~ 673 K. Among investigated samples, the pyrochlore-type Eu2Ti2O7 and Yb2Ti2O7 oxides demonstrate the lowest thermal conductivity and the highest k-values, respectively. These results are similar to those found in literature for their hafnate analogues. It has been shown that the Ln2Ti2O7 thermal conductivity values are lower than those for Ln2Hf2O7 in the all temperature range of measurements.
The specific heat temperature dependences of the rare earth di-titanates were calculated according to the Neumann-Kopp law for the first time and then that were used for computation of thermal conductivity.
In conclusion, the Ln2Ti2O7 phases might be attractive component materials for creating new thermal barrier coatings.
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Alla Kopan' |
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H3- I1547 |
The surface layers formation in Fe-alloys by electric-spark alloying and carbonitriding Galina Lobachova, Ievgen Ivashchenko National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” Electric-spark alloying (ESA) leads to increase of the metal surface hardness and chemical heat treatment can increase the length of the hardened areas into deep of the details. It is possible to create surface areas that have high microhardness, which prevents deformation and fracture at high loads on the surface in the case of consistently carrying out these processing techniques.
Objective: to study the structure, phase composition and microhardness of the Fe-alloys (Fe + 1,5 wt.% Ti; Fe + 2,5 wt.% Cr; Fe) surface at ESA by Ti and Cr and subsequent Carbonitriding.
ESA of samples by Cr- or Ti-anodes was carried out at working voltage 70 V, current 2 A during 3 minutes in air.
Carbonitriding was carried out at temperature 580ОC during 30 minutes.
The structure, microhardness and phase composition of diffusive areas were studied with the use of microstructural, microhardness and X-ray diffraction analysis.
It is shown that after carbonitriding microhardness of Cr- and Ti-coating increases to 7,4-9,9 GPa and 9,9-13,9 GPa depending on the base materials. Titanium coatings have higher microhardness than chromium, due to the strong interaction of Ti with penetration elements (C, N) to form a dispersion of carbides, nitrides, carbonitrides.
As a result of X-ray analysis of iron after ESA by Ti + carbonitriding the (-Fe, Ti, Fe2Ti and nitrides Fe2N, Fe3N were defined; after ESA by Cr we defined the a solid solution of α-(Fe,Cr), carbides Cr3C2, Fe3C and nitrides Fe2N, CrN.
Established that previously applied coating act as a barrier to the penetration of nitrogen and carbon in the succeeding carbonitriding, which reduces the length of hardened layers alloys (Fe + 1,5 wt.% Ti; Fe + 2,5 wt.% Cr). Titanium coating reduces the diffusion length of the zone from 370 to 230 microns in alloys Fe + 1,5 wt.% Ti and from 230 to 180 microns in alloys Fe + 2,5 wt.% Cr in comparison with chrome from 370 to 340 microns and from 230 to 220 microns, respectively.
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Ievgen Ivashchenko |
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H3-VP2125 |
Tribology Properties of Ti₂AlC MAX Phase Based Coatings Deposited By Vacuum Arc Method Viktoriya Podhurska1, Olexander Kuprin2, Roman Chepil1, Orest Ostash1, Tetiana Prikhna3, Volodymyr Sverdun3, Margaryta Bortnitskaya2, Igor Kolodiy2, Vitalii Belous2 1Karpenko Physico-Mechanical Institute of NASU, Ukraine Improving the durability of aircraft engine tribo-couplings that operate in high-temperature and dry friction is an urgent task. The Ti-Al-C MAX phases and their corresponding coatings have a low specific wear rate, mainly due to the formation of specific oxide layers in the friction zone.
The purpose of this work is to investigate the tribological properties of Ti-Al-C coatings at two temperatures, 25°C and 500°C.
The Ti-Al-C coatings were deposited on polished stainless steel samples using a Ti₂AlC MAX phase cathode and the vacuum arc method. TiN coatings were used for comparison. The composition and structure of the coatings were analyzed using XRD, SEM, and EDX methods. Mechanical properties were investigated using a Nano Indenter G200 nanohardness tester. Friction coefficients and wear resistance were tested by reciprocating motion between plates with coatings and a steel ball.
Composite coating consisting of two phases TiC and Ti₃AlC is formed at a potential of -50 V, and at a potential of -100 V, an aluminum-depleted composite is formed TiC+α-Ti. Tribological tests showed that for TiC+Ti₃AlC coatings, the coefficient of friction is µ =0.7 -0.8, and the wear rate w increases from $7.56\cdot 10^{-4}$ at 20°C to $1.81\cdot 10^{-3}$ mm³/Nm at 500°C. TiC+α-Ti coatings have a coefficient of friction at the level of µ =0.5-0.6, and w decreases from $1.26·10^{-4}$ at room temperature to $7.18\cdot 10^{-5}$ mm³/Nm at 500°C in contact with a ball made of steel ШX15. The wear resistance of these coatings is 1.5…2 times higher compared to TiN coatings. There is no definitive correlation between the mechanical properties and the tribological characteristics of the materials.
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Olexander Kuprin |
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H3-JŠ1306 |
Surface laser boronizing of maraging steel parts manufactured by selective laser melting Kęstutis Bučelis, Jelena Škamat, Olegas Černašėjus Vilnius Gediminas Technical University, Lithuania Maraging steel (MSt) is known as a special class of high-strength steels with the specific alloying system providing highly alloyed low-carbon iron-nickel lath martensite matrix, which is aged (annealed) to obtain hardening by intermetallic precipitation. Recently, this steel has been increasingly used in the field of additive manufacturing because it has high resistance to thermal cracking and can be used in the production of parts by selective laser melting. Despite the yield strength of MSt reaches high values (up to ~2420 MPa for commercial grades), it has moderate hardness (~58 HRC max.) and, as a result, insufficient wear resistance under severe working conditions. In the present study, the surface laser alloying process is investigated as a possible way to improve wear resistance of MSt parts.
The samples manufactured by the SLM method and heat treated at 840 (2 h) and 490 (2 h) degrees were coated with a layer of amorphous boron 0.03-0.6 mm thick and processed with a laser beam at different laser speeds (500-1500 mm/min), providing a treatment in a melting mode. The alloying process was performed with the preheating the samples to 400 degrees. Boronized layers in a wide range of hardness from 490 to 2200 HK0.2 with a structure from hypo-eutectic to a mixture of borides were obtained. The effect of the thickness of pre-placed boron paste layer and laser speed on the molten pool geometry and formation of boronized layer was investigated. The nature of cracks formed was studied as well. The hardness distribution along the layers depth and the influence of processing parameters on the softening effect and thickness of the heat affected zone were studied. Two-body dry sliding wear test was conducted to assess their wear resistance. All boronized samples showed an improvement in wear resistance (on average up to ~7.5 times), with the exception of samples having the lowest hardness ~ 490 HK0.2.
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Kęstutis Bučelis |
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H3-SK1639 |
Morphology and properties of nickel deposits obtained by electrocrystallization in a weak induction magnetic field Stanislav Kovalyov, Oleg Girin, Volodymyr Ovcharenko, Vladyslava Mishchenko Ukrainian State University of Chemical Technology, Ukraine Nickel deposits of machine parts are used in industry as functional coatings. This is due to the fact that they have high hardness, excellent reflectivity and high resistance to corrosion damage. It is known that a weak induction magnetic field affects the electrocrystallization and properties of copper deposits.
The aim of our work was determine the chemical, physical (morphology), mechanical properties of nickel deposits in dependence the parameters of electrodeposition in a weak magnetic field.
Methodology. Electrocrystallization of nickel deposits was carried out from a solution containing, mol/l: NiSO47H2O - 0.64, NH4Cl - 0.5, H3BO3 -0.49. The current density is 3 A/dm². A uniform magnetic field with an induction of 1 mT was created around the electrochemical cell. The surface morphology was studied using scanning electron microscopy. The reflectivity was measured with an FB-2 photogloss meter. The microhardness of the deposits was measured with a PMT-3 microhardness tester.
Results. In our work, we have shown that electrocrystallization of nickel in a weak-induction magnetic field affects the electrodeposition process, morphology, and properties of the deposit obtained. The presence of a magnetic field leads to a decrease in the size of grained aggregates. Deposit was obtained close-packed, which affected the reflectivity. The reflectivity was 74% compared to the silver mirror. The microhardness of nickel deposits obtained by electrocrystallization in a magnetic field was, in comparison with the deposits obtained without a magnetic field, increased by more than 1.3 times. The data presented in the work show that the magnetic field affects the properties of deposit.
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Vladyslava Mishchenko |
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H3-MG2053 |
The influence of plasma spraying parameters on microstructure and porosity of bronze-polyester coatings for plain bearings applications Marek Góral, Tadeusz Kubaszek, Barbara Koscielniak Rzeszow University of Technology, Poland The plasma sprayed bronze coatings are widely used for repairing of plain bearing used in different applications. This type of coating was not deeply analyzed in state-of-art publications. In presented article we fill this gap in the case of plasma spraying process.
The influence of power current (I=300/500/700A) and hydrogen flow (0/4/8 NLPM) on microstructure and thickness of aluminium bronze-polyester coating was investigated. The Thermico A60 plasma torch was
used for thermal spray process of coating on flat carbon steel samples (grade S355). The Metco 604NS powder was plasma-sprayed with 20 g/min powder feed rate. The obtained results showed the presence of
local large pores formed by burning of polyester in plasma plume. This pores observed in microstructure plays role of oil pockets in bearings. The obtained coatings were characterized by large deviation in
thickness in range 200-350 micrometers and high porosity about 20 vol. %.
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Marek Góral |
Contacts
Conference Secretary: Storozhenko Maryna
E-mail: conference@umrs.org.ua
E-mail: conference@umrs.org.ua