α-Si_3N_4と水酸化アルミニウム溶液から得たβ-サイアロン焼結体の室温強度

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β-sialon, with z=0.5, was fabricated by hot-pressing of a spray dried mixture of a-Si_3N_4 powder and aluminumhydroxide aqueous solution prepared by hydrolysis and peptization of aluminum-iso-propoxide. Flexural strength, phase composition and microstructure of the sintered bodies have been investigated. Phases identified by XRD in the sintered body were β-sialon and σ sialon. Hydrolization of Si_3N_4 during mixing with aluminumhydroxide solution gave an increasing amount of σ sialon compared with a sample prepared without water i. e. , aluminum-iso-propoxide dissolved in C_6H_<14> solution. The microstructure study showed that β-sialon consisted of 0.5-2 μm equiaxed grains and a small amount of 2-5μm plate-like grains which was assumed to be σ sialon. The room temperature flexural strength (3-point bending) was 119 kg/ mm^2. This value was slightly lower than that of β-sialon obtained from aluminum-iso-propoxide solution. However it was remark-ably higher than that of β-sialon obtained from Al_2O_3 powder mainly due to a finer and more homogeneous microstructure. The degradation of the strength as compared with β-sialon from aluminum-iso-propoxide solution has been; explained by the existence of plate like grains which occurred due to a higher amount of oxygen from the hydrolysis of Si_3N_4.
社団法人日本セラミックス協会の論文
1988-05-01