Preparation of silicon carbide ceramics using chemical treated powder by DCC via dispersant reaction and liquid phase sintering

Abstract

Dense silicon carbide ceramics using chemical treated powder by DCC via dispersant reaction method and liquid phase sintering was reported. Ammonium peroxydisulfate ((NH4)2S2O8) and ammonium carbonate ((NH4)2CO3) were used as acid and base solutions to treat the silicon carbide powder, respectively. Influence of silicon carbide powder with chemical treatment on the preparation of silicon carbide suspension was studied. It was indicated that 50vol% and 52vol% silicon carbide suspensions with viscosities of 0.71Pas and 0.80Pas could be prepared using acid and base treated powders. Influence of silicon carbide powder with chemical treatment on the coagulation process and properties of green bodies and sintered ceramics were studied. It was indicated that silicon carbide green bodies with compressive strength of 1.13MPa could be prepared using base treated powder. Dense silicon carbide ceramics with relative density above 99.3% and flexural strength of 697±30MPa had been prepared by DCC via dispersant reaction and liquid phase sintering using Al2O3 and Y2O3 as additives at 1950°C for 2h.