Effect of Micropowder Introduction on Synthesis of SiAlON-bonded SiC Products

摘要

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 1450℃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????m increase from 30%to 68%;CO resistance reaches level A.