Effect of thermal exposure on microstructural and mechanical characteristics of reaction sintered SiC based materials

The microstructure and the mechanical properties of RS-SiC and RS-SiCf/SiC materials suffered from the thermal exposure have been investigated in conjunction with both the residual silicon content and the porosity. RS-SiC based materials have been fabricated using the complex matrix slurry with different composition ratios of SiC and C particles. The characterization of RS-SiC based materials was investigated by means of SEM, EDS and three point bending test. The room temperature strength of RS-SiC material, which depended on the content of residual silicon, largely decreased with the increase of the thermal exposure times, due to large amount of porosities. The strength of RS-SiCf/SiC composites also tended to decrease at the temperature higher than 1000degreesC.