アルミニウムイソプロポキシド溶液とSi₃N₄粉末の相互作用

抄録

The dispersability of Si₃N₄ powder in n-C₆H₁₄ and Al(Oi-Pr)₃/n-C₆H₁₄, and the amount of Al(Oi-Pr)₃ adsorbed on the surface of Si₃N₄ particles after mixing Al(Oi-Pr)₃/n-C₆H₁₄ and Si₃N₄ were examined. The zeta-potential of the powder prepared by spray-drying and calcining a mixture of Al(Oi-Pr)₃/n-C₆H₁₄ and Si₃N₄ was measured. The dispersablity of Si₃N₄ in Al(Oi-Pr)₃/n-C₆H₁₄ was much higher than in n-C₆H₁₄, due to the formation of-Al(Oi-Pr)_n layer on Si₃N₄ particle surfaces. The Si₃N₄ powder which was separated from the mixture of Al(Oi-Pr)₃/n-C₆H₁₄ and Si₃N₄ by filtration after hydrolysis by addition of water and peptization by addition of diluted HCl at pH 2, contained 0.07wt% Al. The isoelectric point of the powder which was prepared by spray-drying and calcining the mixture of Al(Oi-Pr)₃/n-C₆H₁₄ and Si₃N₄ was about 8.2, while that of Si₃N₄ was 5.5. These results suggested that Si₃N₄ particles were coated with a γ-Al₂O₃-like layer.