DENSE SiC CERAMIC PRODUCTS

摘要

PCT No. PCT/AU90/00518 Sec. 371 Date Jun. 20, 1991 Sec. 102(e) Date Jun. 20, 1991 PCT Filed Oct. 26, 1990 PCT Pub. No. WO91/06515 PCT Pub. Date May 16, 1991.A process for the liquid phase sintering of silicon carbide, comprising forming a shaped, consolidated powder body which, not allowing for binder, comprises a powder mixture containing at least 75 wt % silicon carbide and from 1 to 25 wt % (calculated as Al2O3) of a powder comprising a source of aluminum selected from alumina, precursors for alumina and mixtures thereof. The body is heated in a non-oxidising atmosphere to a sintering temperature of from 1500 DEG C. to 2300 DEG C. to form a liquid phase and a resultant liquid phase sintered body. In said heating step, the body is heated in the presence of a source of magnesium which is distinct from the source of aluminum and comprises at least one of magnesia, precursors for magnesia, magnesium vapour and combinations thereof, whereby said liquid phase produces secondary oxide constituent.