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Journal of the Korean Ceramic Society 1990;27(7): 851. |
$Al_2O_3$로 피복시킨 세라믹 복합분체의 제조 및 특성 : (I) 피복용 혼합 알루미늄 염 용액의 가수분해 |
현상훈, 정형구 |
연세대학교 요업공학과 |
Preparation and Characteristics of Ceramic Composite Powders Coated with $Al_2O_3$: (I) Hydrolysis of Mixed Aluminum Salt Solution for Coating |
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ABSTRACT |
The hydrolysis-precipitation reaction of mixed aluminum salt solutions of aluminum sulfate, aluminum nitrate, and urea has been investigated to obtain narrow-sized and unagglomerated fine spherical precipitates of aluminum hydroxide required for coating core particles. The hydrolysis-precipitatin reaction could be controlled to be appropriate to coating processes by usign urea as a pH control-agent. As the concetration of total Al3+ ion and the molar ratio of SO42-/Al3+ in starting solutions became smaller and also as the vol. ratio of water/solution for hydrolyzing mixed aluminum salt solution became larger, the morphology of precipitates tended to be more unagglomerated and spherical, while their size(0.5longrightarrow0.05${mu}{textrm}{m}$) to be smaller. The optimum hydrolysis condition for coating processes was to hydrolyze the mixed aluminum salt solution, in which the molar ratio of SO42-/Al3+ was 0.75, while the amount of water corresponding to the vol. ratio of water/solution of 15. The precipitate was the aluminum hydroxide which sulfate ions were strongly adsorbed on and the maximum yield in the hydrolysis-precipitation reaction was about 20%. |
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