Preparation and characterisation of alumina-based composite support layers

Abstract

Porous ceramic membranes are of special interest owing to their outstanding thermal and chemical stability. However, porous ceramic membranes with permeability usually suffer from low mechanical strength. Therefore, there have been a number of studies of the optimisation of membrane mechanical strength and permeability. In this paper, to avoid a trade-off between mechanical strength and permeability, we attempt to enhance these parameters by incorporating diatomite as both a pore former and a bonding phase. Because the flexural strength and air permeability of alumina support layers cannot be enhanced simultaneously by just changing the sintering temperature, we investigate whether they can be controlled by changing the amount of added diatomite. We study the effectiveness of diatomite as both a pore former and a bonding phase through a comparison of alumina–diatomite and the alumina–pyrophyllite composite support layers.