Effects of sintering temperature on properties of porous mullite/corundum ceramics

In this paper, porous mullite/corundum ceramics with high porosity, high strength and low thermal conductivity were fabricated by foam-gelcasting method using fused mullite powder as raw material. Effects of sintering temperature on linear shrinkage, bulk density, apparent porosity, compressive strength and thermal conductivity of the porous mullite/corundum ceramics were researched. As sintering temperature increased from 1350 to 1550 °C, linear shrinkage increased from 2.6 to 9.5%, porosity decreased from 81 to 78%, bulk density increased from 0.59 to 0.69 g/cm3, compressive strength increased from 3.1 to 11.7 MPa and thermal conductivity increased from 0.14 to 0.35 W/m·K. Porous microstructure was complex, where large spherical pores contained small cellular pores on their internal walls.