High strength and high hardness alumina-zirconia-silicon carbide

Abstract

An alumina-zirconia-silicon carbide sintered ceramic composite having high strength and high hardness is composed of 5 to 50 volume percent of partially stabilized zirconia powder of mean particle size between 0.1 and 1.0 .mu.m, 3 to 40 volume percent of silicon carbide powder of mean particle size smaller than 1 .mu.m or silicon carbide whiskers of 1 .mu.m or less in diameter with an aspect ratio between 3 and 200 or combination of said silicon carbide powder and said silicon carbide whiskers, the balance being substantially alumina powder, wherein zirconia plus silicon carbide accounts for 55 volume percent at most of the total. The sintered ceramic composite is manufactured by making a mixed powder composed of 5 to 50 volume percent of partially stabilized zirconia powder of mean particle size between 0.1 and 1.0 .mu.m, 3 to 40 volume percent of silicon carbide powder of mean particle size smaller than 1 .mu.m or silicon carbide whiskers of 1 .mu.m or less in diameter with an aspect ratio between 3 and 200 or combination of said silicon carbide powder, and said silicon carbide whiskers, the balance being substantially alumina powder, wherein zirconia plus silicon carbide accounts for 55 volume percent at most of the total, and then sintering the molded mixed powder at a temperature between 1400.degree. and 1800.degree. C. Further, the mixed powder to be molded and sintered is made on a ball mill equipped with a pot made of one or more of the ceramic materials of which such sintered ceramic is composed.