Abstract: The production of a reaction-bonded silicon carbide artefact by siliconizing a green body comprising a coherent mixture of carbon and silicon carbide particles includes the step of forming a layer of carbon of open cellular structure on the green body by carbonization of a sleeve or tube on the green body by carbonization of a sleeve or tube of carbonaceous material in contact with the body. This material may be impregnated with particulate silicon suspended in water or a paste. The material may be a quilted or woven fabric of fibrous material or it may be in the form of paper. The material is in a flexible strip or sheet form to enable it to be wrapped around the green body or a former about which the green body is to be formed.

Abstract: A silicon carbide-silicon matrix composite incorporates unreacted coarse carbon particles (e.g. graphite particles) dispersed throughout the composite. The coarse particles are incorporated in a coherent mixture of carbon and silicon carbide powders which, after compaction, is infiltrated with molten silicon to form a matrix of reaction bonded silicon carbide in a substantially continuous free silicon carbide phase. By using coarse carbon particles of density of at least 0.963 g/ml, the molten silicon reacts only with the surfaces of those particles which may as a result remain unreacted and dispersed throughout the composite.

Abstract: Reaction-bonded silicon carbide artefacts are produced by siliconizing a green body formed from a coherent mixture of silicon carbide and carbon powders. The surface of the green body is coated with a paste comprising silicon powder suspended in a carbonizable viscous medium which, on heating of the coating, is converted to an open cellular carbon structure and then, on siliconizing the green body, to a silicon carbide skeleton through which molten silicon is drawn.