Mechanical reinforcement of carbon foam by hafnium carbide deposit

Hafnium carbide made by chemical vapour deposition is being investigated as promising coating and mechanical reinforcement of carbon foams used at high temperature (above 3000 degrees C). This substrate presents an exceptionally high open porosity (98 %) with a characteristic size of 65 pores per inch. The chemical composition of HfC deposit are determined by both electrical resistivity and Auger electron spectroscopy. The experimental conditions leading to an uniform thickness coating on the reticulated open cell foam are optimized. The evaluation and measurements of the reinforcement effect of such a coating on carbon foam properties are studied by compressive mechanical testing at room temperature and 2500 degrees C.