Siliconizing
siliconizing
[′sil·ə·kə‚nīz·iŋ]Siliconizing
the surface or volume saturation of a material with silicon. Siliconizing is effected by treating the material either in silicon vapors, which are formed above a silicon charge at high temperatures, or in a gaseous medium containing chlorosilanes. The chlorosilanes are reduced by hydrogen, for example, according to the reaction SiCl4 + 2H2 = Si + 4HC1. Siliconizing is used primarily as a means of protecting refractory metals (W, Mo, Ta, Ti) from oxidation. Resistance to oxidation is brought about by the formation of dense, self-healing, diffused suicide coatings (WSi2, MoSi2) during the siliconizing process. Siliconized graphite has found widespread application. [23–1081–]