A process has been developed for obtaining closed cell metallic foams using a ceramic foam precursor based on chemically bonded ceramics. In the present study, the major constituent of the ceramic foam precursor was iron oxide (Fe2O3) which was mixed with various foaming/setting additives. The mixture set rapidly at room temperature due to the reaction of acidic phosphates with metal oxides, stabilizing the foam generated by hydrogen release. The chemically bonded ceramic foam was then reduced by heating at 1240°C in a non-flammable hydrogen/inert gas mixture to obtain metallic foams with a relative density of 0.12--0.24, and average cell diameters on the range of 1--2mm. The compressive stress-strain curves obtained were typical of cellular metals. The normalized strengths of the metal foams obtained in the present study compare favorably with those of steel foams produced by other techniques. The rate of reduction was five times lower than previously reported values.
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