Comparative Studies of Vapor and Liquid-Phase Impregnation of Porous Silicon Nitride and Silicon Carbide Materials

摘要

Purpose was to produce dense Si sub 3 N sub 4 and SiC bodies without using foreign additives, in order to avoid their negative effect on creep above 1000 exp 0 C. Although stress-free bodies can be produced by reaction sintering (RB = reaction bonding), they are highly porous and post-densification must be achieved by impregnation. RB Si sub 3 N sub 4 was impregnated with polysilanes and then subjected to pressure pyrolysis. Densification by CVD was also investigated. It is concluded that the goals of densification, solidification, reduction of creep rate and improvement of oxidation resistance, have been attained. 85 figures, 11 tables. (ERA citation 09:031235)