Mechanisms of Interaction of Molybdenum and Tungsten Polyoxide with Aluminum Oxide Melt under Reducing Conditions
- Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,” (Russian Federation)
The main chemical reactions between Mo and W polyoxides and Al{sub 2}O{sub 3} melt in a controlled Ar + H{sub 2} atmosphere (T = 2400 K, P = 1 bar) during sapphire growth by horizontal directional solidification have been investigated. Under these thermodynamic conditions, the melt and products of its dissociative evaporation may actively react with the tungsten heater and molybdenum thermal screens of the crystallization system. It is shown that the polyoxides formed during evaporation do not directly interact with the melt; this interaction occurs only with participation of reagents exhibiting pronounced reducing properties (Al, H{sub 2}, H, WO, Al{sub 2}O, AlH, AlH{sub 2}, AlH{sub 3}). It is established that most of processes occur with participation of aluminum hydrides. A particular role of Mo(W) dioxide–W(Mo) polyoxide functional pairs in the interaction with the melt is determined.
- OSTI ID:
- 22758210
- Journal Information:
- Crystallography Reports, Journal Name: Crystallography Reports Journal Issue: 4 Vol. 63; ISSN 1063-7745; ISSN CYSTE3
- Country of Publication:
- United States
- Language:
- English
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