Fine Strontium Ferrite Powders from an Ethanol-Based Microemulsion

Authors

  • Jiye Fang,

    1. Department of Materials Science, Faculty of Science, National University of Singapore, Singapore 119260, Republic of Singapore
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  • John Wang,

    1. Department of Materials Science, Faculty of Science, National University of Singapore, Singapore 119260, Republic of Singapore
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    • *

      Member, American Ceramic Society.

  • Leong-Ming Gan,

    1. Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 119260, Republic of Singapore
    2. Institute of Materials Research and Engineering, Faculty of Science, National University of Singapore, Singapore 119260, Republic of Singapore
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  • Ser-Choon Ng,

    1. and Department of Physics, Faculty of Science, National University of Singapore, Singapore 119260, Republic of Singapore
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  • Jun Ding,

    1. Department of Materials Science, Faculty of Science, National University of Singapore, Singapore 119260, Republic of Singapore
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  • Xiangyuan Liu

    1. Department of Materials Science, Faculty of Science, National University of Singapore, Singapore 119260, Republic of Singapore
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  • L. Levinson—contributing editor

  • Supported by the National University of Singapore, under Research Grant No. RP3979900, and the Institute of Materials Research and Engineering (IMRE), under Research Grant No. GR6611.

Abstract

A fine strontium ferrite powder with high coercivity was successfully prepared by forming hydroxide precursor particles in the continuous ethanol-based phase of a microemulsion consisting of iso-octane, NP9, and an ethanol solution containing Sr2+ and Fe3+ cations at a molar ratio of 1:12. The microemulsion-derived hydroxide precursor was calcined at various temperatures, ranging from 600° to 1100°C, to develop the hexagonal strontium ferrite phase. X-ray diffractometry and infrared characterizations revealed that the formation mechanisms of strontium ferrite in the microemulsion-derived precursor differed from those of the precursor derived by conventional coprecipitation. The microemulsion resulted in a strontium ferrite of finer particle size and better magnetic properties than those of the conventionally coprecipitated strontium ferrite. The microemulsion-derived strontium ferrite exhibited an intrinsic coercivity of 6195 Oe and a saturation magnetization of 58.28 emu/g when calcined at 900oC. The saturation magnetization increased further, to 69.75 emu/g, when the microemulsion-derived precursor was calcined at 1100oC.

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