Preparation of SiC-AIN Ceramic Alloy Powder by Direct Reaction between Constituent Elements and Property Evaluation of its Sintered Compacts

Abstract

Fine powders of SiC-A1N ceramic alloy were synthesized by direct reactions of a powder premix of Si, C and Al powders in nitrogen, i.e. Si+C+xAl+(x/2)N₂=SiC:xAIN. The synthesized powders showed a good sinterability; dense compacts were fabricated by hot-isostatic pressing at relatively low temperature (2123K) without additives, or by pressureless sintering with Y₂O₃ as a sintering additive. The obtained SiC-A1N alloys showed better mechanical properties than the monolithic SiC and A1N; for example a two to threefold increase in fracture strength was achieved.