抄録
To improve the fracture toughness of sintered bodies, a method for in-situ dispersion of SiC platelets was studied. A mechanically alloyed powder mixture consisting of Si, C, B and W (the mixing ratio was Si/C=1/1 in molar ratio, and 3mass% C, 3mass% B and 5mass% W were added as sintering additives) was sintered above 2100°C in Ar atmosphere. By using the mechanical alloyed powder mixture, ceramics reinforced with β-SiC platelet in length of 100μm and thickness of 5μm, was obtained. Two possible mechanisms of the formation of a β-SiC platelet have been proposed; (a) W and B in the SiC phase are supersaturated by mechanical alloying process, (b) W-B phase is separated from the SiC phase during sintering, and then, SiC platelets grow. A W-containing compound formed in the reaction sintered SiC suppresses the phase transition from β-SiC to α-SiC.
