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Microstructure and Coercivity of Rare Earth Magnets

Research Project

Project/Area Number 63460199
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 金属材料(含表面処理・腐食防食)
Research InstitutionThe University of Tokyo

Principal Investigator

UMEDA Takateru  the University of Tokyo, Department of Metallurgy, Professor, 工学部, 教授 (50011078)

Co-Investigator(Kenkyū-buntansha) NAGAYAMA Katsuhisa  the University of Tokyo, Department of Metallurgy, Research assistant, 工学部, 助手 (80189167)
SUZUKI Toshio  the University of Tokyo, Department of Metallurgy, Associate Professor, 工学部, 助教授 (70115111)
Project Period (FY) 1988 – 1989
Project Status Completed (Fiscal Year 1989)
Budget Amount *help
¥8,700,000 (Direct Cost: ¥8,700,000)
Fiscal Year 1989: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1988: ¥6,600,000 (Direct Cost: ¥6,600,000)
KeywordsNd_2Fe_<14>B / microstructure / metastable grain boundary / coercivity / Sm_2Co_<17> / TbCu_7 / TbCu_7 / 急冷薄帯 / Nd_<15>Fe_<77>B_8合金 / 液体急冷法 / 準安定相 / セル構造 / 保磁力 / 結晶配向
Research Abstract

High coercivity of 23 kOe was obtained on melt-spun Nd_<15>Fe_<77>B_8 ribbons with 40-100 m in thichness. The samples which showed high coercivity contained a new metastable boundary phase with 20-80 nm in width Nd_2Fe_<14>B grains were surrounded with this phase and they formed smooth and coherent interface structures. These microstructures indicated a strong pinning effect on the motion of the domain wall. The new phase was identified by analysis of electron diffraction patterns as a tetragonal structure with lattice constants of a=0.512 nm, and c=0.801 nm. By heat treatment over than 760 K, it was decomposed into fcc-Nd and a small amount of NdFe_4B_4. Interface structures between Nd_2Fe_<14>B and grain boundaries became incohent and also coercivity decreased.
The vertical sections of Sm-Co-Cu-Fe quaternary and Sm-Co-Cu-Fe -Zr quinary phase diagrams were determined in composition range from 6 to 16 at%Sm. The 2/17 phase has hexagonal TbCu_7, hexagonal Th_2Ni_<17> and rhombohedral Th_2Zn_<17> type structures. Only alloys with TbCu_7 phase at high temperature have superior magnetic properties with high coercivity. The Sm content with 2/17 single phase of TbCu_7 type structure shifts to the Sm-poor side with addition of Zr.

Report

(3 results)
  • 1989 Annual Research Report   Final Research Report Summary
  • 1988 Annual Research Report
  • Research Products

    (14 results)

All Other

All Publications (14 results)

  • [Publications] 岩村栄治: "Nd_<15>Fe_<77>B_8急冷薄帯における準安定相" 日本金属学会誌. 52. 1301-1302 (1988)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] 岩村栄治: "液体急冷法により作製したNd_<15>Fe_<77>B_8薄帯における準安定粒界相と高保磁力に対する効果" 日本金属学会誌. 54. 111-116 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Yoshio MORITA: "MRS Int'l.Mtg.on Adv.Mats.vol.11." Meterials Research Society, 11 (1989)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Eiji IWAMURA: "Proc.of the 10th International Workshop on Rare-Earth Magnets and Their Applications(II)." The Society of Non-Traditional Technology, 7 (1989)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Eiji Iwamura, Katsuhisa Nagayama, Toshio Suzuki and Takateru Umeda: "Metastable Phase in Melt-Spun Nd_<15>Fe_<77>B_8 Ribbons" J.Japan Inst.Metals, 52, pp.1301-1302, 1988.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Yoshio Morita, Takateru Umeda and Yasuo Kimura: "Phase Diagrams for Sm_2Co_<17> Magnets" MRS Int'l.Mtg.on Adv.Mats.11, pp.97-107, 1989.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Eiji Iwamura, Katsuhisa Nagayama, Tosho Suzuki, and Takateru Umeda: "High Coercivity of Melt-Spun Nd_<15>Fe_<77>B_8 Ribbons with a New Metastable Boundary Phase" Proc.of the 10th International Workshop on Rare-Earth Magnets and Their Applications (2), pp.293-301, 1989.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Eiji Iwamura, Katsuhisa Nagayama, Tosho Suzuki, and Takateru Umeda: "Structure of the New Metastable Grain Boundary Phase in Melt-Spun Nd_<15>Fe_<77>B_8 Ribbons and its Roles on High Coercivity" J.Japan Inst.Metals, 54, pp.111-116, 1990.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] 岩村栄治: "Nd_<15>Fe_<77>B_8急冷薄帯における準安定相" 日本金属学会誌. 52. 1301-1302 (1988)

    • Related Report
      1989 Annual Research Report
  • [Publications] 岩村栄治: "液体急冷法による製作したNd_<15>Fe_<77>B_8薄帯における準安定粒界相と高保磁力に対する効果" 日本金属学会誌. 54. 111-116 (1990)

    • Related Report
      1989 Annual Research Report
  • [Publications] 岩村栄治: 日本金属学会誌. 52. 1301-1302 (1988)

    • Related Report
      1988 Annual Research Report
  • [Publications] 岩村栄治: 日本金属学会誌投稿予定.

    • Related Report
      1988 Annual Research Report
  • [Publications] 吉田 裕: 日本金属学会誌投稿予定.

    • Related Report
      1988 Annual Research Report
  • [Publications] 永山勝久: 日本金属学会誌投稿予定.

    • Related Report
      1988 Annual Research Report

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Published: 1988-04-01   Modified: 2016-04-21  

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