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43XV International Symposium on Self-Propagating High-Temperature Synthesis
STRUCTURE AND PHASE FORMATION IN ALUMINUM OXYNITRIDE DURING SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS
T. G. Akopdzhanyan*", A. A. Kondakov", N. A. Kochetov", S. I. Rupasovfi, A. P. KozlovaA, and A. V. BondarevA
aMerzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, Moscow, 142432 Russia
bNational University of Science and Technology MISiS, Moscow, 119049 Russia *e-mail: tigran@ism.ac.ru
DOI: 10.24411/9999-0014A-2019-10005
Nowadays high-temperature nitride and oxyde ceramics takes one of the leading places among novel materials for various industries: electronics, radio, aircraft and space engineering, nuclear industry.
One of the most promising materials for creating polycrystalline ceramics with high mechanical and unique physicochemical properties is aluminum oxynitride with a cubic crystal structure (y-AlON). AlON ceramics is well known due to its excellent optical and mechanicals properties and could be used in various application fields. To obtain high-quality polycrystalline AlON ceramics it is necessary to ensure high purity AlON powders with narrow particle distribution.
The main synthesis methods of AlON powder are solid state reaction of AlN and AhO3 and carbothermal reduction of AhO3 at temperatures higher than 1700°C for a few hours. Recently, a lot of other methods such as plasma arc melting, nitriding of a precursor derived from aluminum-glycine gel method, etc. were developed. These methods have some disadvantages such as high cost of initial materials (for example AlN), carbon impurities (which cause pores in sintered ceramics), low energy efficiency and complexity of the technology. Self-propagating high-temperature synthesis (SHS) is a highly efficient method to produce powders and ceramics, especially nitride ceramics.
Earlier, we showed the possibility of obtaining pure aluminum oxynitride for ceramics, including optical ceramics. In this work, the possibility of controlling the structure and phase formation in AlON is investigated. The effect of initial components of green mixture on the structure and phase composition of AlON is also studied. The possibility of obtaining a bimodal structure is studied, which will make it possible to obtain a bimodal distribution of particles in powders. The influence of oxides of rare-earth metals on the phase composition and structure of the material is also studied.
The work was funded by RFBR (project no.19-08-00655).
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