In situ growth of elongated α-sialon grains in Li-α-sialon ceramics

In situ growth of elongated α-sialon grains has been studied in Li-α-sialon ceramics. The morphology of α-sialon grains is mainly determined by the overall composition, with low m and high n values promoting the anisotropic grain growth of α-sialon needles with even more pronounced effects at higher sintering temperatures and pressures. β-Si3N4 starting powder can also facilitate the growth of elongated α-sialon grains since it reduces the number of sites where α-sialon grains can nucleate. The effects of processing parameters on the growth of elongated α-sialon grains were examined. For single-phase α-sialon starting compositions, increases in sintering time do not promote the elongated (or even equiaxed) growth of α-sialon grains after the formation of α-sialon is complete.