Preparation of Al2O3-ZrO2 Composite Powders by the Use of Emulsions: I. Thermodynamic Model of the Emulsion Stability

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J. Korean Ceram. Soc. > Volume 24(6); 1987 > Article

Journal of the Korean Ceramic Society 1987;24(6): 593.

에멀젼을 이용한 Al2O3-ZrO2 복합분체의 제조 : I. 에멀젼 안정화에 대한 열역학적 모델

한상훈, 백종규, 송승룡

연세대학교 요업공학과

Preparation of Al2O3-ZrO2 Composite Powders by the Use of Emulsions: I. Thermodynamic Model of the Emulsion Stability

ABSTRACT

A thermodynamic model to predict the stability of the water-in-oil type emulsion and the size of the droplets in stable emulsions was developed. Using this model, the effects of various factors government the droplet size in the metal salt solution-kerosene-span 80 system for the preparation of Al2O3-ZrO2 composite powders were investigated. It was shown that the given emulsion systems were thermodynamically unstable in every case but could be kinetically meta stable. When radius ofthe droplet was below nm, the increase in entropy change due to the configurational contribution of small droplets dominated the total free energy change for emulsification. The optimum conditions under which smaller deoplet was obtained were proposed and the validity of the model was proved with diameters of the droplet and composite powders experimentally determined.