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

DOI: 10.62564/M4-TS1241

Tetiana Serbeniuk¹, Tetiana Prikhna¹, Oleksii Kalenyuk^2,3, Sergii Futimsky^2,3, Volodymyr Sverdun¹, Andrii Shapovalov^2,3, Miroslav Karpets<sup>1,4,5

1</sup>Bakul 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 constant 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 established 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 measurements of electrodynamic characteristics showed that the developed new composite materials 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 particular, arrangement of conductive phases grains (C, Mo₂C) in the structure of composites and minimization of contacts between them.

Keywords
composite material, AlN, graphite, dielectric constant, electrodynamic properties

Acknowledgments
Not provided

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.