China's Refractories

Abstract: This work aims at preparing SiAlON-bonded SiC products with high SiAlON contents. Silicon carbide fines, micropowders of Si, Al and alumina with different activities were premixed in a ball mill to obtain different composite micropowders. Then silicon carbide particles, the composite micropowders and binder were wet mixed. After shaping the specimens were fired under insulation from direct flame in a shuttle kiln at 1 450 ℃ in nitrogen atmosphere. The chemical composition, microstructure, pore size distribution and CO resistance of the prepared specimens were tested. The results showed that: after introducing high-activity micropowder additives the SiAlON content grows from 14.8 mass% to 23.5 mass%; the amount of unreacted alumina and silicon nitride in the specimens falls from 8.78 mass% to 1.79 mass%; micropores with size under 1 μm increase from 30% to 68%; CO resistance reaches level A.