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1992 Fiscal Year Final Research Report Summary

High Temperature Deformation and Coercivity of R_2Fe_<14>B compound

Research Project

Project/Area Number 02402046
Research Category

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

Allocation TypeSingle-year Grants
Research Field 金属加工(含鋳造)
Research InstitutionThe University of Tokyo

Principal Investigator

UMEDA Takateru  The Univ.of Tokyo,Faculty of Engineering,Professor, 工学部, 教授 (50011078)

Co-Investigator(Kenkyū-buntansha) NAGAYAMA Kazuhisa  Shibaura Institute of Technology,Faculty of Engineering,Lecturer, 工学部, 講師 (80189167)
Project Period (FY) 1990 – 1992
KeywordsNd_2Fe_<14>B / Pr_2Fe_<14>B / Pr_6Fe_<13>Cu / Coercivity / Boundary phases / Hot deformation / Antiferromagnetic
Research Abstract

Rare earth magnets of Nd_2Fe_<14>B that has high magnetic saturation and crystal magnetic anisotropy have been made mainly by the sintering and the rapid solidification processing. In 1988 Shimoda et al. showed that Pr_2Fe_<14>B has a hot deformability and a new type of magnetos was inroduced by utilizing the relation between the magnetic anisotropy and casting and deformation ones. Therefore rare earth magnets by a common metals processing route of casting, hot deformation and heat-treatment are expected to develop. In this research we investigated magnetic properties and micro structures determined by each processing. Hot pressing was divided into three deformation stages. At initial stage a rapid increase in stress with deformation resulted in fine cracks inside the sample that induced heavily stress relaxation. At second stage liquid existed in the boundary healed cracks and crystal grains were reoriented to the direction of flow stress that caused the anisotropy. At final stage the samples were damaged by a heavier deformation. Primary Fe particles disappeared by the soaking process and a lower temperature soaking brought about fine structures that resulted in high coercivity and energy product was formed during the annealing of 600゚C and its formation caused high coercivity. Pr_6Fe_<13>Cu that is formed by peritectic reaction is tetragonal and antiferromagnetic. Materials design is requested with consideration to the coupling between ferromagnetic and antiferromagnetic phases. Other new boundary phase Nd(Pr)_<11>Fe_<87>B_2.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] 梶谷 敏之: "Pr-Fe-B系磁石材料のプロセッシングと磁性" 東京大学工学部紀要. A-29. 46-47 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Toshiyuki Kajitani: "Microstructure of Cu-added Pr-Fe-B magnets:Crystallization of antiferromagnetic Pr_6Fe_<13>Cu in the boundary reqion" Journal of Magnetism and Magnetic Materials. 117. 379-386 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Toshiyuki Kajitani: "Microstructure Pr-Fe-B Magnets with added Cu:Crvstallization of Anitiferromagnetic Pr_6Fe_<13>Cu in the boundary" Proceedings of the 12th International workshop on Rare-earth Magnets and their Applications. 574-584 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 永山 勝久: "Fe-Pr-B3元系鉄コーナー部の状態図作製と凝固反応" 日本金属学会誌.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Kajitani,K.Nagayama,N.Niwa and T.Umeda: "Material Processing and Magnetic Properties of Pr-Fe-B Hard Magnets" J.Fac.Eng.,Univ.Tokyo. A-29. 46-47 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Kajitani,K.Nagayama and T.Umeda;Microstructure of Cu-added Pr-Fe-B magnets:Crystallization of Antiferromagnetic Pr_6Fe_<13>Cu in the boundary region: Journal of Magnetism and Magnetic Materials. 117,No.3. 379-386 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Kajitani,K.Nagayama and T.Umeda: "Microstructure Pr-Fe-B Magnets witch added Cu:Crystallization of Antiferromagnetic Pr_6Fe_<13>Cu in the boundary" Proceedings of the 12th International Workshop on Rare-earth Magnets and their Applications. 574-584 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Nagayama and T.Umeda: "Construction of Phase Diagram and Solidification Reaction on Fe Comer of Fe-Pr-B Temary System" Journal of the Japan Institute of Metals.

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

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Published: 1994-03-24  

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