Gelcasting of alumina foams consolidated by epoxy resin

A water-soluble epoxy resin combined with a polyamine hardener was developed to consolidate foamed suspensions to manufacture alumina foams. This gelling system could be carried out in air atmosphere, thus more convenient than those based on acrylamide derivatives. The influence of solid loading on the viscosity of suspensions as well as on the relative density of sintered foams was evaluated. The resulting alumina foams, with relative densities between 17% and 38%, comprised microstructures of spherical cells. Both the flexural strength and the compressive strength of the foams had a power law relation against the relative density. The permeability of sintered foams decreased exponentially with the relative density.