Microstructure of ceramic foams

This paper describes the preparation of ceramic foams by expansion of a cer amic suspension based on a polyurethane system. The microstructure and degr ee of reticulation of the foamed ceramic were examined and analysed with th e help of a simple geometrical model. Like the porous ceramics prepared by the replica processing method, these foamed ceramics possess open cells in a nearly equiaxed shape but the cell size is much finer. The ratio of the w indow size to the cell size is a useful parameter for characterising the ge ometry of the foam and is related to the qualitative concept of degree of r eticulation. For a face centred cubic array of cells it is related geometri cally to the volume fraction of porosity and this relationship is tested us ing microstructural measurements for a range of ceramic foams. (C) 2000 Els evier Science Ltd. All rights reserved.