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2002 Fiscal Year Final Research Report Summary

Physical Properties of Oxide Thermoelectric Materials Prepared by the Polymerized Complex Method

Research Project

Project/Area Number 12650714
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Material processing/treatments
Research InstitutionOsaka University

Principal Investigator

KATSUYAMA Shigeru  Osaka Univ., Grad. School of Eng., Associate Prof., 大学院・工学研究科, 助教授 (00224478)

Project Period (FY) 2000 – 2002
KeywordsPolymerized Complex Method / Thermoelectric Materials / Seebeck Coefficient / Electrical Resistivity / Thermal Conductivity / Zinc Oxide / Layered Co-oxide / Control of Microscopic Structure
Research Abstract

In this Study we have prepared the oxide thermoelectric materials with controlled microscopic structure by the polymerized complex method, and measured their physical properties. It is generally considered that the polymerized complex method is a convenient method for preparing various oxide materials. We have investigated the Zn_<1-x>Al_xO and Layered-Na_xCo_2O_4 systems. Stoichiometric amounts of metal nitrate hydrate and citric acid were dissolved in ethylene glycol. The solution was concentrated and the viscous polymerized complexes were formed. These polymeric products were decomposed to a fine and uniform powder in air. In the case of Zn_<1-x>Al_xO system the obtained powder was sintered by SPS (Spark Plasma Sintering) apparatus at 1100℃ for 10min at a pressure of 10〜30MPa, while in the case of Na_xCo_2O_4 system the obtained powder was sintered by Hot-Pressing at 900℃ for 1〜2h at a pressure of 25MPa. The phase identification of the samples was made by X-ray diffraction and the m … More icroscopic structure of the samples was examined using SEM. The physical properties such as Seebeck coefficient, the electrical resistivity and thermal conductivity of the samples were measured. The crystal grain size of Zn_<1-x>Al_xO prepared by the polymerized complex method is about 1〜2μm, which is much smaller than that by the conventional solid state reaction method, 10μm. The absolute value of the Seebeck coefficient and the electrical resistivity for Zn1-xAlxO generally decreases with increasing Al content of x. Comparing theses values at fixed Al content between the samples prepared by the polymerized complex and solid state reaction methods, the samples by the polymerized complex method have smaller values. There is almost no difference in the thermal conductivity between these samples, although the crystal grain size of the former is much smaller. These results indicate that the more homogeneous samples were obtained by the polymerized complex method and the doping of the carrier into the material can be more easily realized in the samples prepared by the polymerized complex method. On the other hand, NaxCo2O4 ceramics prepared by the polymerized complex method show higher crystallographic anisotropy than that by the solid state reaction method, and have lower electrical resistivity maintaining moderate Seebeck coefficient. As a result, lager figure of merit was obtained on the samples prepared by the polymerized complex method. Less

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] 勝山茂, 吉岡大貴, 井藤幹夫, 真島一彦, 永井宏: "錯体重合法によるZn_<1-x>Al_xOの作製とその熱電特性"粉体および粉末冶金. 47. 619-624 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Katsuayma, Y.Kanayama, M.Ito, K.Majima, H.Nagai: "Thermoelectric Properties of CoSb_3 with FeSb_2 Particles Dispersion"J.Appl.Phys.. 88. 3484-3489 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Katsuyama, S.Tokuno, M.Ito, K.Majima, H.Nagai: "Phase Relation and Thermoelectric Properties of the Ternary Lanthanum Chalcogenide System L-A-S (A=Ca, Ba)"J Alloys and Compounds. 320. 126-132 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Katsuyama, Y.Takagi, M.Ito, K.Majima, H.Nagai et al.: "Thermoelectric Properties of (Zn_<1-y>Mg_y)_<1-x>Al_xO Ceramics Prepared by the Polymerized Complex Method"J.Appl.Phys.. 92. 1391-1398 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Nagira, M.Ito, S.Katsuyama: "Thermoelectric Properties of Na_xCo_2O_4 Prepared by the Polymerized Complex Method and Hot-Pressing"Materials Transactions. 44. 155-160 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 勝山茂: "錯体重合法により作製した酸化亜鉛系熱電変換材料の物性"生産と技術. 55. 13-18 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Katsuyama, H.Yoshioka, M.Ito, K.Majima and H.Nagai: "Thermoelectric Properties of Zn_<1-x>Al_xO Prepared by the Polymerized Complex Method"J. Japan Society of Powder and Powder Metallurgy. 47(6). 619-624 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Katsuyama, Y.Kanayama, M.Ito, K.Majima and H.Nagai: "Thermoelectric Properties of CoSb_3 with FeSb_2 Particles Dispersion"Appl. Phys.. 88(6). 3484-3489 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Katsuyama, S.Tokuno, M.Ito, K.Majima and H.Nagai: "Phase Relation and Thermoelectric Properties of the Ternary Lanthanum Chalcogenide System La-A-S (A=Ca, Ba)"J. Alloys and Compounds. 320. 126-132 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Katsuyama, Y.Takagi, M.Ito, K.Majima, H.Nagai et al.: "Thermoelectric Properties of (Zn_<1-y>Mg_y)_<1-x>Al_xO Ceramics Prepared by the Polymerized Complex Method"J. Appl. Phys.. 92(3). 1391-1398 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nagira, M.Ito and S.Katsuyama: "Thermoelectric Properties of Na_xCo_2O_4 Prepared by the Polymerized Complex Method and Hot-Pressing"Materials Transactions. 44(1). 155-160 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Katsuyama: "Thermoelectric Properties of Al-substituted Zinc Oxide Prepared by the Polymerized Complex Method"The Production & Technique. 55(1). 13-18 (2003)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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