Colloidal Processing and Slip Casting of Mullite

Abstract

Mullite an aluminosilicate ceramic due to its excellent refractory, mechanical and dielectric properties find wide applications as structural and high temperature ceramics as well as for electric and optical applications. Slip casting is a well established shaping or forming method to fabricate ceramic shapes having simple to reasonably complicated shapes. In the present study commercially available mullite powders were characterized for crystallographic phase purity, particle size distribution and morphology. The optimum dispersion condition of the powder in de-ionised water was studied through measurement of zeta potential as a function of pH. The mullite powder dispersed in deionised water with and without addition of MgO was slip cast in plaster mould. The slip cast samples were sintered at different temperatures to study the effect of MgO addition on the sinterability of mullite. The products were characterized for density, porosity and microstructure.