The Characteristics of Water Based Ferrofluid of Magnetite Prepared by Air Oxidation

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J. Korean Ceram. Soc. > Volume 27(1); 1990 > Article

Journal of the Korean Ceramic Society 1990;27(1): 109.

공기산화법으로 제조한 Magnetite의 물분산매 자성 유체의 특성

신학기, 장현명¹, 한창덕², 김태옥²

경남전문대학 화공과
¹포항공과대학 재료공학과
²부산대학교 무기재료공학과

The Characteristics of Water Based Ferrofluid of Magnetite Prepared by Air Oxidation

ABSTRACT

Magnetite for Water-based ferrofluid was synthesized by air oxidation of aqueous suspension in the pH range 7-12 at $65^{circ}C$. The optimum condition of magneite formation was delineated by examining various physicochemcial properties such as Fe2+ content, phase characteristics, MHC and $sigma$max. The point of zero charge of iron oxide powders obtained at various pH conditions were correlated with the oxidation state of Fe in the iron oxide. The magnetite powder prepared at pH 9 ws dispersed using sodium oleate and sodium dodecylbenzenesulfonate (SDBS) as dispersants, and the dispersion characteristics of the magnetite ferrofluid were examined by means of the fraction of solid dispersed, zeta potential data and FT-IR spectrum. A simple calculation on the potential energy of two interacting magnetite particles showed that the dispersion stability was directly correlated with height of the potential energy barrier or the shape of zeta potential.