JP2925089B

PURPOSE:To obtain high toughness at a low cost by using Si3N4 containing two or more selected from Y2O3, Er2O3, etc., as sintering auxiliary agents or a rare earth metal, MgO, etc., as a matrix and blending an SiC particle having a prescribed size as a reinforcing material therewith. CONSTITUTION:A matrix (A) is obtained by blending Si3N4 containing two or more sintering auxiliary agents selected from Y2O3, Er2O3, Tm2O3, Yb2O3 and Lu2O3 or a rare earth metal, MgO, ZrO2, etc. A reinforcing material (B) consisting of an SiC platy particle having 5-50mum maximum diameter and a thickness smaller than 1/3 thereof is then added thereto in an amount of 3-50vol.% based on the (A) component to obtain a mixed powder (C). The mixed powder (C) is then subjected to plasma-arc forming and the resultant formed material (D) is sintered at 1500-2000 deg.C and 9-9.9kg.f/cm under vacuum or in a nonoxidative atmosphere using the hot press method, thus producing the objective ceramics composite sintered material.