a process for preparing a silicon carbide foam by impregnating a polyurethane foam with a suspension of silicon powder in an organic resin , heating progressively to polymerize the resin , heating further to carbonize the polyurethane foam and resin , and finally further heating to carburize the silicon contained in the resin suspension by means of carbon obtained from the carbonization of the foam and resin . the foam obtained is characterized by high macroporosity and a mesoporosity which is variable according to the carburizing temperature .