Method of making molten silicon infiltration reaction products and products made thereby

Claim 1

Composites comprising, (A) a contiguous machinable exterior layer, and (B) a refractory base structure, where the contiguous machinable exterior layer (A) is the infiltration product of reaction by molten silicon, and a substantially uniform mixture comprising by volume, from 45% to 90% of particulated carbon having up to an equal proportion by volume, based on the total volume of the mixture, of silicon carbide particles, and from 10% to 55% of a particulated inorganic material selected from the class consisting of boron nitride, aluminum oxide, magnesium oxide, and silicon nitride, substantially inert to molten silicon at temperatures up to 1600° C., having an average particle size of from 0.1 to 2000 microns, and a Mohs hardness value falling within the range of 1-7, and the refractory base structure (B) is a member selected from the class of shaped silicon carbide refractories and the infiltration product of reaction by molten silicon and a carbon fiber preform.