J. Korean Ceram. Soc. > Volume 35(6); 1998 > Article
 Journal of the Korean Ceramic Society 1998;35(6): 543.
 에멀젼 증발법에 의한 산화텅스텐 분말의 제조에 관한 연구 신창훈, 안종관, 이응조 고려대학교 공과대학 재료·금속공학부 A Study on the Preparation of Tungsten Oxide powders Using Emulsion Evaporation Methods ABSTRACT A process for the preparation of spherical tungsten oxide powders by the emulsion evaporation method was developed. The characteristics of the powders thus prepared were examined by means of TGA X-ray diffraction SEM and image analysis. The emulsion was prepared by fast mixing of tungsten containing aque-ous phase and the organic phase which contained kerosene surfactant and paraffin oil. The precursor was made by evaporating the emulsion in the kerosene bath at $160^{circ}C$ and then calcined at $650^{circ}C$ in order to pro-duce tungsten oxide powders. The average particle size of the tungsten oxide powders was $0.5;mutextrm{m}$ and their shapes were spherical. Water-in-oil type emulsion wasmore advantageous to make less agglmerated. $W_{3}$ powders than the oil-in-water type emulsion for the emulsion evaporation experiments. As the HLB value of the surfactant increased and the concentration of tungsten ions in the aqueous phase decreased the mean particle size of tungsten oxide powders decreased whereas agglomeration increased. The optimum con-centration of Span 80 was 8 percent by volume and the optimum stirring speed in the emulsion formation was 5000 rpm in order to obtain find less agglomerated $W_{3}$ powders. Key words: Emulsion, Tungsten, $W_{3}$ powders, Emulsion evaporation, Surfactant
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