Ultrafine Barium Titanate Powders via Microemulsion Processing Routes

Authors

  • John Wang,

    1. Department of Materials Science, Department of Physics, Department of Chemistry, and Institute of Materials Research and Engineering, National University of Singapore, Singapore 119260
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    • Member, American Ceramic Society.

    • Department of Materials Science.

  • Jiye Fang,

    1. Department of Materials Science, Department of Physics, Department of Chemistry, and Institute of Materials Research and Engineering, National University of Singapore, Singapore 119260
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    • Department of Materials Science.

  • Ser-Choon Ng,

    1. Department of Materials Science, Department of Physics, Department of Chemistry, and Institute of Materials Research and Engineering, National University of Singapore, Singapore 119260
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    • Department of Physics.

  • Leong-Ming Gan,

    1. Department of Materials Science, Department of Physics, Department of Chemistry, and Institute of Materials Research and Engineering, National University of Singapore, Singapore 119260
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    • Department of Chemistry.

    • Institute of Materials Research and Engineering.

  • Chwee-Har Chew,

    1. Department of Materials Science, Department of Physics, Department of Chemistry, and Institute of Materials Research and Engineering, National University of Singapore, Singapore 119260
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    • Department of Chemistry.

  • Xianbin Wang,

    1. Department of Materials Science, Department of Physics, Department of Chemistry, and Institute of Materials Research and Engineering, National University of Singapore, Singapore 119260
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    • Department of Physics.

  • Zexiang Shen

    1. Department of Materials Science, Department of Physics, Department of Chemistry, and Institute of Materials Research and Engineering, National University of Singapore, Singapore 119260
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    • Department of Physics.


  • P. P. Phule—contributing editor

  • Supported by Research Grant No. RP960692 from the National University of Singapore.

Abstract

Three processing routes have been used to prepare barium titanate powders, namely conventional coprecipitation, single-microemulsion coprecipitation using diether oxalate as the precipitant, and double-microemulsion coprecipitation using oxalic acid as the precipitant. A single-phase perovskite barium titanate was obtained when the double-microemulsion-derived oxalate precursor was calcined for 2 h at a temperature of as low as 550°C, compared to 600°C required by the single-microemulsion-derived precursor. A calcination for 2 h at >700°C was required for the conventionally coprecipitated precursor in order to develop a predominant barium titanate phase. It was, however, impossible to eliminate the residual TiO2 impurity phase by raising the calcination temperature, up to 1000°C. The microemulsion-derived barium titanate powders also demonstrated much better powder characteristics, such as more refined crystallite and particle sizes and a much lower degree of particle agglomeration, than those of the conventionally coprecipitated powder, although they contained ∼0.2 wt% BaCO3 as the impurity phase.

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