Coercivities of Sm-Fe-M sintered magnets with ThMn12-type structure (M = Ti, V)

Kazuki Otsuka, Masayuki Kamata, Tadao Nomura, Hiroki Iida, Hajime Nakamura

Research output: Contribution to journalArticlepeer-review

Abstract

Sm-Fe-M (M= Ti, V) sintered magnets with the ThMn12-type structure which consist of higher Sm content than the stoichiometric composition of ThMn12-type compound, were produced by the powder-metallurgy. Sm-Fe-Ti sintered magnets had a low level of coercivities of about 10kAm-1. In contrast, Sm-Fe-V anisotropic sintered permanent magnets, particularly, Sm10.5Fe74.1V15.4 magnet exhibited magnetic properties with a coercivity of 648.7kAm-1, a remanence of 0.73T and a (BH)max of 97.6 kJm-3. Through microstructure observation of the grain boundary between the adjacent ThMn12-type grains using STEM, no grain boundary phases were observed in Sm10.0Fe81.7Ti8.3 magnet, whereas two types were observed in Sm10.5Fe74.1V15.4 magnet: an amorphous structure with a thickness of about 1 nm and an incomplete periodic structure with a thickness of about 2 nm. EDS analysis indicated that the composition ratios of Sm to the sum of Fe and V were about 1 to 1 and 1 to 1.7, respectively. It suggested that the existence of a grain boundary phase is important to raise coercivity.

Original languageEnglish
Pages (from-to)887-891
Number of pages5
JournalMaterials Transactions
Volume62
Issue number6
DOIs
Publication statusPublished - 2021
Externally publishedYes

Keywords

  • Anisotropic magnet
  • Coercivity
  • Grain boundary phase
  • Sintered magnet
  • ThMn-type structure

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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