Effect of Porosity on Thermal Conductivity and Flexural Strength of Ceramic Foam

Abstract

Refractory ceramics used for thermal insulating applications should be porous; containing large number of air cells.This work addresses a highly porous local ceramic prepared via simple and low cost process (direct foaming method) by using Iraqi raw material (kaolin) and egg white as a binder and a foaming agent. Porosity, thermal conductivity and flexural strength were obtainedafter sintering of the specimens at 1100 and 1300 oC. The prepared ceramic foam contained a large amount of spherical microspores; it has high porosity (68.1-80%), low thermal conductivity (0.2-0.6) W/m.K with flexural strength range (0.4-2.8) MPa.The direct foaming method, using egg white foam, proved to be an efficient and feasible method for producing highly porous ceramics with good mechanical properties for thermal insulating applications.