In situ synthesis of Ti3SiC2/SiC composite by displacement reaction of Si and TiC

In situ synthesis technology was adopted to fabricate SiC reinforced Ti3SiC2 composite by displacement reaction of Si and TiC powders. The formation of SiC particles as reinforcements with elongated or equiaxed shape distributed in Ti3SiC2 matrix. The average size of SiC equiaxed particles was about 2 mum and that of elongated ones was in the range of 5-8 mum in length and 2 mum in width. TiC with about 1 mum in size was also found in the composite. The particles of SiC or TiC inhibited the grain-boundary migration of Ti3SiC2 resulting in a fine Ti3SiC2 matrix with a grain size of 10 mum Differential scanning calorimetry showed that Si reacted drastically with TiC at 1340degreesC with release of heat. The presence of TiC in the Ti3SiC2/SiC composite should be attributed to decomposition of Ti3SiC2 at 1500degreesC rather than the loss of Si during reaction process that resulted in unreacted TiC left. Reaction paths in the present experiment were postulated on the basis of Ti-Si-C system and reaction model of Mo2C-Si to understand the mechanism of the formation of Ti3SiC2 and SiC. (C) 2004 Elsevier B.V. All rights reserved.