Thermal Properties of Monolithic Silica and Silica-Zirconia with Bimodal Pore Structures

Abstract

Thermal properties of bimodal porous silica and silica-zirconia with humidity control ability are investigated in order to clarify their potential as a multi-functional building material. Thermal conductivity of the silica decreases with increasing the porosity of the silica, and 0.06 W m^-1K^-1 is achieved when the porosity exceeds 90%. The silica shows thermal resistance of ca. 800°C, which is much higher than conventional thermal insulators. The thermal resistance can be improved by the addition of zirconia: a silica-zirconia sample maintains its high porosity up to 1050°C. Thus, the bimodal porous silica and silica-zirconia are expected to be a thermal insulator with humidity control and thermal resistance abilities.