Controlling heat radiation for development of high-temperature insulating materials

Conventional industrial insulating materials have a porous structure, and provide good resistance to conduction. However, at high temperatures greater than 1000 °C, this structure permits heat transfer through radiation. In recent years, many high-performance insulating materials have been developed that consist of nanosized particles and pores. Such materials have a thermal conductivity less than 0.1 W/(m K) up to 800 °C. However, it has very less heat resistance over 1000 °C.In this study, we have developed an insulating material which has a great suppress radiation and its thermal conductivity was less than 0.3 W/(m K) at 1500 °C. The insulating material was considered to be porous magnesium aluminate spinel of two different pore sizes, 0.05–1 and 1–5 μm, with a porosity of 78%. Among the two pores, the 1–5 μm pores were more efficient to restrain heat transfer through radiation.