Estimation of thermal shock resistance of fine porous alumina by infrared radiation heating method

Abstract

The thermal shock resistance of α-alumina porous capillary, the support material for hydrogen-permselective microporous ceramic membrane was studied. To study the effect of porosity on the thermal shock resistance systematically, porous alumina with different porosities was fabricated, and the thermal shock resistance of the fabricated samples as well as the porous capillary was estimated by the infrared radiation heating method. The mechanical and thermal properties concerned to the thermal shock resistance were also measured and the effect of the porosity on the properties was carefully examined. The fracture strength was not changed with temperature, but decreased with the porosity. The fracture toughness, Young's modulus and thermal conductivity were also decreased with porosity. Thermal shock resistance of porous alumina was estimated quantitively by the experimental thermal shock parameters, thermal shock strength, R_1c and thermal shock fracture toughness, R_2c. The thermal shock parameters of porous alumina were much lower than dense alumina, and decreased with porosity due to the decreasing of fracture strength and thermal conductivity. The experimental thermal shock strength was good accordance with that calculated from the material properties in this study. Thermal shock strength of porous alumina capillary at service temperature could be estimated by the comparison experimental and calculated thermal shock strength.