CORRELATION OF GREEN MICROSTRUCTURE OF AL2O3 WITH COLLOID/INTERFACE VARIABLES

Abstract

Density and microstructure of A12O3 green bodies were analyzed in terms of kinetic stability and interfacial characteristics of colloidal suspension. Density and the most frequent pore diameter of Al2O3 green bodies were directly correlated with the critical stability ratio (W(c)) and critical zeta potential (xi(c)). These observations were explained using concepts of the critical stability ratio, critical zeta potential and the potential energy barrier between two interacting particles in a ceramic slip. Analysis of data indicated that the potential energy barrier between two interacting colloid particles should be higher than its critical value for fabricating of A12O3 green bodies with dense and uniform microstructure. A rapid decrease in the most frequent pore diameter occurred for a green compact prepared from a kinetically stable slip having the stability ratio larger than a certain critical value, demonstrating a direct influence of colloid/interface variable on pore microstructure of Al2O3 green bodies.