Effects of YAG-phase amount on the microstructure and phase transformation during the liquid-phase sintering of β-SiC

beta-silicon carbides with yttrium aluminum garnet(YAG) of 2, 5, 10 mol% were prepared by a liquid-phase sintering, and the microstructural evolution and phase transformation were investigated during sintering as functions of liquid-phase (YAG) amount and sintering time. By increasing the amount of YAG addition in the SiC starting powder, the rate of grain growth during sintering decreases, but the apparent density and the aspect ratio of grains in sintered body increase. The phase transformation from beta- to alpha-SiC was enhanced by increasing the liquid-phase amount, and the kinds of transformed polytypes of alpha-silicon carbide were dependent on the liquid-phase amount and sintering time.