Prodn. of reaction-bonded silicon carbide bodies - by flowing elemental molten silicon into compact of silicon carbide grain and carbon

摘要

Reaction bonded SiC body is formed by heating in an inert atmos. or a vacuum to a temp. of at least the m.pt. of Si a porous compact (I) of a uniform mixt. of SiC grain and finely divided elemental C in contact with a mixt. (II) of finely divided Si and a small amt. of finely divided C. A portion of the Si in (II) reacts with the C in (II) to form a porous, friable SiC matrix which guides the flow of molten Si from (II) to (I), where it reacts with the C to form additional SiC and produce a reaction bonded SiC body. Used esp. in the prodn. of SiC sealing rings for rotary pump shafts etc. Prod. is easily machined since excess Si is easily removed, and there is no need for the amt. of Si or C in (I) or the porosity of (I) to be closely controlled since the use of excess Si ensures quality control.