Surface Properties and interfacial Potential Distribution of Surface Treated-Alumina

,; ,; ,; ,

J. Korean Ceram. Soc. > Volume 33(7); 1996 > Article

Journal of the Korean Ceramic Society 1996;33(7): 823.

표면처리한 알루미나의 표면물성과 계면전위분포

홍영호, 함영민¹

혜전전문대학 공업화학과
¹단국대학교 공과대학 화학공학과

Surface Properties and interfacial Potential Distribution of Surface Treated-Alumina

ABSTRACT

Due to the intrinsic low surface activation of ${gamma}$-alumina it has been used limitely in practice. Accordingly forward enhancing its utility ${gamma}$-alumina surface was treated with slfuricf aicd nitric acid and chloric acid respec-tively. Subsequently the effects of surface activity on the surface electrical characteristics were investigated. The ${gamma}$-alumina was prepared by the precipitation of aluminium nitrate [Al(NO3)3.9H2O] using ammonia water as a precipitator and it was chemically treated with such acids mentioned above. The surface and morphology of the acid-treated ${gamma}$-alumina were analysed by XRD, BET and the surface activities were measured by the amine titration methods. The interfacial properties of the ${gamma}$-alumina dispersed in electrolyte solution were esti-mated by the surface charge density measured using potentiometric tiration. Based on the relation between surface charge density and the acid amount the following results were drawn for the surface and interfacial electrical properties ; Acidic properties of surface-treated alumina increase with anion load on alumina surface. P. Z. C decreases with acid amount on alumina surface. The surface charge densities were apart from electrolyte ionic strength. The acidity of ${gamma}$-alumina is linearly dependent on the P. Z,.C when the ${gamma}$-alumina was dispersed in aqueous electrolyte solution.

Key words: Surface treatment, Surface activity, Electic potential, Ionization constants