Thermal shock resistance of porous ceramic materials

Thermal expansion properties of porous alumina and silicon carbide ceramics were examined using a dilatometer. Thermal shock resistance property of the ceramics were studied by water-quenching method, and strength and elastic modulus of the ceramics before and after thermal shock experiments were examined. The average thermal expansion coefficient of porous alumina and silicon carbide ceramics were 8.49×10^-6/K and 1.14×10^-6/K, respectively. The results show that the thermal shock resistance of silicon carbide is better than that of alumina and the residual strength of the ceramic materials decreases with increasing of temperature difference. The residual strength and thermal stress of porous silicon carbide ceramic is checked and a critical temperature difference exists for thermal shock experiment of the ceramic, and its elastic modulus decreased with the increase of temperature difference. The critical temperature difference of the porous silicon carbide is 300-400°C.