2021 Volume 58 Issue 11 Pages 596-602
In recent years, new thermal insulation materials with lower thermal conductivity and lightweight have been fabricated. However, due to the problems such as heat resistance, their practical use is limited to only below 1000°C. In this paper, the thermal insulation performance of fibrous fumed alumina compacts was evaluated by repeatedly measuring the thermal conductivity at temperatures up to 1200°C. As a result, it revealed that the compacts have low thermal conductivity of 0.040–0.065 W/(m·K) between 200°C and 1000°C. After receiving the heat processing up to 1200°C, its thermal conductivity rapidly increased. However, it was less than half of that of existing ceramic fiber insulation. The compressive strength and flexural strength also increased by the repeated heat processing. The increase of thermal conductivity by the repeated heat processing was explained by the increase of solid thermal flux due to the sintering of particles in the compact and the increase in thermal radiation flux due to the surface oxidation of SiC particles.
