Thermoelectric Properties of NaxCo2O4 Prepared by the Polymerized Complex Method and Spark Plasma Sintering

• Nagira Tomoya

  Department of Materials Science and Processing, Graduate School of Engineering, Osaka University

• Ito Mikio

  Department of Materials Science and Processing, Graduate School of Engineering, Osaka University

• Katsuyama Shigeru

  Department of Materials Science and Processing, Graduate School of Engineering, Osaka University

• Hara Shigeta

  Department of Materials Science and Processing, Graduate School of Engineering, Osaka University

書誌事項

タイトル別名

• Thermoelectric Properties of Na<SUB>x</SUB>Co<SUB>2</SUB>O<SUB>4</SUB> Prepared by the Polymerized Complex Method and Spark Plasma Sintering

抄録

Na_xCo₂O₄ powders were synthesized using the polymerized complex (PC) method and then the polycrystalline samples were prepared by the spark plasma sintering (SPS) method. The microstructure and thermoelectric properties of these samples were evaluated, and their differences due to the preparation process of the polycrystalline Na_xCo₂O₄ samples were investigated. The crystal grain sizes of the annealed PC samples after SPS at 1073 K and 1173 K were much smaller than that of the sample prepared by the conventional solid-state reaction (SSR) method and the sintered PC sample without pressure. Their relative densities were greater than 99%. We have obtained the dense sintered Na_xCo₂O₄ samples with a finer microstructure. In the case of the annealed PC sample after SPS at 1073 K, the thermoelectric power, α, was remarkably higher than that of the SSR sample, and the α value was as high as that of the PC sample without pressure. The electrical resistivity, ρ, increased because of its finer crystal grains compared to the SSR sample and the sintered PC sample without pressure. In the case of the annealed PC sample after SPS at 1173 K, the ρ was the lowest of all samples in spite of its finer microstructure. Based on these results, the power factors of the annealed PC samples after SPS at 1073 K and 1173 K were markedly higher than that of the SSR sample over the entire temperature range. For the annealed PC sample after SPS at 1073 K, the maximum power factor, 1.4×10⁻³ W/mK², was obtained at 1073 K.

収録刊行物

• MATERIALS TRANSACTIONS

  MATERIALS TRANSACTIONS 44 (9), 1866-1871, 2003

  公益社団法人 日本金属学会

キーワード

• Na<SUB>x</SUB>Co<SUB>2</SUB>O<SUB>4</SUB>
• thermoelectric properties
• polymerized complex method
• spark plasma sintering

詳細情報

• CRID: 1390001204246977408
• NII論文ID: 130004452276
• NII論文ID: 10011915000
• NII書誌ID: AA1151294X
• DOI: 10.2320/matertrans.44.1866
• COI: 1:CAS:528:DC%2BD3sXos1Glt7k%3D
• ISSN: 13475320
• ISSN: 13459678
• NDL書誌ID: 6692090
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I6692090
• Web Site: https://www.jstage.jst.go.jp/article/matertrans/44/9/44_9_1866/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可