Abstract
The effect of a subsurface layer of metal silicide on the phase composition stability of high-temperature MeSi2-type coatings on refractory metals was investigated. Using the system WSi2 ― W as a prototype it was experimentally determined that a subsurface layer of the tungsten disilicide, and the distribution profile of silicon in the diffusion zone upon high-temperature heating have a substantial effect on the formation of a barrier layer of lower silicide which determines the stability of the system as a whole. It is proposed that the search for more stable silicide coatings on refractory metals should be directed toward the creation of diffusion barriers on not only the inner interface MeSi2 ― Me, but also the external surface of the coating. The process of coating formation must be accompanied by the formation of a metal silicide on the external surface with the highest possible concentration of silicon.
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Zmii, V.I., Kovtun, N.V. Stability and Heat Resistance of Silicide Coatings on Refractory Metals. Part 1. Effect of Subsurface Layer on Process of Phase Redistribution in System WSi2 ― W. Powder Metallurgy and Metal Ceramics 41, 395–399 (2002). https://doi.org/10.1023/A:1021121227445
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DOI: https://doi.org/10.1023/A:1021121227445