Silicon carbide whisker-reinforced silicon nitride composite material and process for producing the same.

摘要

An SiC whisker-reinforced Si3N4 composite material comprising a sintered body of an Si3N4 matrix having dispersed therein SiC whiskers, wherein said SiC whiskers are uniaxially orientated; a process for producing an SiC whisker-reinforced Si3N4 composite material which comprises mixing (1) SiC whiskers having a coating comprising an oxide of at least one metallic element selected from the group consisting of Be, Mg, Ca, Sr, and Ba of the group 2A; Sc, Y, and La of the group 3A; Ti, Zr, and Hf of the group 4A; and Li, A l , and Si with (2) Si3N4 powder, and sintering the mixture; and a process for forming said metal oxide coating on the surface of whiskers which comprises dipping whiskers in a solution of an inorganic or organic salt of at least one metallic element selected from the group consisting of the elements of the groups 2A, 3A, and 4A of the periodic table, Li, and A l and heat treating the whiskers having adhered thereto the metallic salt at a temperature not less than the thermal decomposition temperature of said metallic salt. The SiC whisker-reinforced Si3N4 composite material exhibits improved strength particularly at high temperatures and improved toughness.