REACTION-INHIBITION DURING SINTERING OF SIC WITH AL2O3 ADDITIONS

The mechanisms and products of the reactions which occur during the si ntering of SiC with Al2O3 as a sintering aid were analysed. The effect s of two sintering atmospheres, namely pressurised CO acid Ar gases, o n the reaction thermodynamics and reaction products were investigated. Thermodynamically predicted reaction products were correlated with ex perimentally determined reaction products. The observed weight losses and the final sintered densities are explained on the basis of the pro posed reaction mechanisms. The major finding of the present analysis i s that a pressurised CO gas atmosphere greatly enhances the densificat ion characteristics of SiC ceramics.