Preparation of silicium carbide foam from a polyurethane foam impregnated with silicium-containing resin.

摘要

Process for the preparation of a silicon carbide foam consisting in attacking a polyurethane foam with an alkaline solution, in impregnating it, after rinsing and drying, with a suspension of silicon powder in an organic resin, in heating gradually to polymerise the resin, in carbonising the polyurethane foam and the resin, finally carbiding the silicon present in the resin suspension with the carbon originating from the carbonisation of the foam and of the resin. The foams obtained are characterised by a high macroporosity and a mesoporosity which can vary depending on the carbiding temperature. The invention finds its application in the manufacture of catalyst supports for exhaust silencers and filters for diesel engines.