Preparation and Properties of High-Purity Porous Calcium Hexaluminate Material

In this paper, high-purity porous calcium hexaluminate materials were prepared with α-alumina, nano-meter calcium carbonate and ρ-alumina as raw materials. The properties of the prepared porous materials, such as bulk density, true density, thermal conductivity, and cold crushing strength, were investigated. The increase in sintering temperature led to the increase of true density. Bulk density and cold crushing strength of the specimen fired at 1500°C had the lowest values. As ρ-alumina content increased, bulk density, true density, and cold crushing strength had no obvious changes, but the thermal conductivity decreased at first and then increased. The calcium hexaluminate formation was intense from 1450°C to 1500°C and finished at 1500°C. Above 1500°C, the main phase of specimens was calcium hexaluminate (CA 6 ). And CA 6 grains were regular hexagonal plates morphology and widely spread after firing at 1550°C.