SiC Material Produced by Carbothermal Reduction of a Freeze Gel Silica-Carbon Artefact.

Abstract A carbon–silica artefact was produced by infiltration of phenolic resin into the macroporous texture of a silica sample followed by subsequent carbonisation. The silica material was manufactured using an original sol–gel method. This work reports on the conversion into SiC of the silica–carbon artefact heat-treated up to 1550 °C under different gaseous environments. The extent of the carbothermal reduction was followed by thermogravimetric analysis, X-ray diffraction, gas adsorption and scanning electron microscopy. Experiment results demonstrate that a β-SiC artefact with a shape similar to the starting material is obtained by heat treatment of the carbon-silica artefact above 1470 °C. Quantitative formation of SiC is observed by lowering the partial pressure of CO in the reactor. Moreover, the as-obtained SiC material exhibits a granular aspect associated with a significant specific surface area. In a more general way, the procedure described in this work to obtain the SiC material may be a promising route for designing ceramic materials with specific properties.