Preparation of silicon nitride-silicon carbide composites from abrasive SiC powders

Silicon nitride - silicon carbide composite was developed by using an abrasive SiC powders as a raw material. The composites were prepared by mixing abrasive SiC powder with silicon, pressing and sintering at 1400 degrees C under nitrogen atmosphere in atmosphere controlled vacuum furnace. The proportion of silicon in the initial mixtures varied from 20 to 50 wt%. After sintering, crystalline phases and microstructure were characterized. All composites consisted of alpha-Si3N4 and beta-Si3N4 as the bonding phases in SiC matrix. Their physical and mechanical properties were also determined. It was found that the density of the obtained composites increased with an increase in the Si3N4 content formed in the reaction.