Effect of Rare-earth Substitution for Ca on High-temperature Thermoelectric Properties and Microstructure of Ca<SUB>3</SUB>Co<SUB>4</SUB>O<SUB>9</SUB>

DOI
  • NONG NGO VAN
    Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, 816-8580, Japan CREST, Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012
  • OHTAKI MICHITAKA
    Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, 816-8580, Japan CREST, Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012

説明

Polycrystalline Ca3-xLnxCo4O9 (x < 0.5) samples with Ln = Dy, Ho, Er and Lu for x < 0.5 were prepared using hot-pressing (HP) technique and investigate the influence of rare-earth substitution for Ca on their thermoelectric properties and microstructure. With the Ln substitution, high-temperature thermopower increases and both the thermal and electrical conductivities decrease. However, the decrease in the electrical conductivity is more substantial in low temperature region (T < 600 K) than that in higher temperature region. High-temperature thermoelectric figure-of-merit is significantly improved by the Ho and Lu substitutions, particularly those for the Lu-doped samples. From scanning electron microscope (SEM) observation, sheet-like grains are thinner and smaller in size for the Ln-doped samples than those for non-doped one.

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詳細情報 詳細情報について

  • CRID
    1390282680591939968
  • NII論文ID
    130006971908
  • DOI
    10.14853/pcersj.2007f.0.200.0
  • 本文言語コード
    en
  • データソース種別
    • JaLC
    • CiNii Articles
  • 抄録ライセンスフラグ
    使用不可

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