Thermal shock resistance of pressureless sintered SiC/AlN ceramic composites

This paper conducts for the first time, a study of thermal shock resistance properties of different pressureless sintered SiC/AlN ceramic composites. SiC/AlN composites with different AlN content (0-40 wt%) were obtained by pressureless sintering of SiC and AlN powders at temperature of 2080 °C/2 h in Ar/vacuum atmosphere with using 2.5% yttria and alumina as sintering aids. The different ceramic composites are subjected to 20 thermal shock/water quenching cycles at temperature of 700 °C. Mechanical strength and microstructure investigation before and after thermal shock exposure were used to evaluate thermal shock properties and durability of the different composites. It was found that, the investigated carbide/nitride ceramics gave high thermal shock resistance without any cracking or spalling with retention of about 70% of its original strength. Results suggest that, SiC/AlN composites are strong candidate in severe thermal shock resistance environments.