REACTION INJECTION MOLDING OF SILICON NITRIDE CERAMICS HAVING CRYSTALLIZED GRAIN BOUNDARY PHASES

摘要

Lukacs /A Matsumoto Case 1 REACTION INJECTION MOLDING OF SILICON NITRIDE CERAMICS HAVING CRYSTALLIZED GRAIN BOUNDARY PHASES A sintered, Si3N4-containing ceramic article is prepared by a reaction injection molding process comprising (1) injecting into a heated mold a fluid, nondilatant mixture of (a) at least 40% by volume of a powder mixture of (i) Si3N4, (ii) a silicate glass-forming sintering aid and (iii) a high metal content silicide, and (b) a curable Si3N4 precursor binder, to cure the binder and produce a hardened molded article, (2) heating the hardened molded article under a suitable atmosphere to convert the cured binder to a Si3N4-containing ceramic, and (3) sintering the molded article under a vacuum to crystallize the silicate glass phase by deoxygenation.