Elemental Distribution near the Grain Boundary in a Nd–Fe–B Sintered Magnet Subjected to Grain-Boundary Diffusion with Dy₂O₃

• Itakura M.

  Department of Engineering Sciences for Electronics and Materials, Faculty of Engineering Sciences, Kyushu University Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Science and Engineering, Kyushu University

• Namura M.

  Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Science and Engineering, Kyushu University

• Nishida M.

  Department of Engineering Sciences for Electronics and Materials, Faculty of Engineering Sciences, Kyushu University Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Science and Engineering, Kyushu University

• Nakamura H.

  Magnetic Materials Research Center, Shin-Etsu Chemical Co., Ltd.

Bibliographic Information

Other Title

• Elemental Distribution near the Grain Boundary in a Nd-Fe-B Sintered Magnet Subjected to Grain-Boundary Diffusion with Dy₂O₃

Abstract

We have investigated the microstructure in a Nd–Fe–B sintered magnet subjected to the grain-boundary diffusion (GBD) process with Dy₂O₃. It was found that thin (Nd,Dy)₂Fe₁₄B shells with a thickness of at least 10 nm and an average Dy concentration of approximately 0.7 at% were formed even at the center of the specimen, at a depth of approximately 1 mm from the specimen surface. However, the area fraction of the fcc NdO phase remained almost constant at approximately 3% throughout the magnet irrespective of depth, and the grain-boundary wetting phase hardly changed except in the vicinity of the surface. Furthermore, the thickness (ca. 3 nm) and structure (amorphous) of the thin grain boundary phase existing between Nd₂Fe₁₄B grains remained almost unchanged by the Dy-GBD process, despite the formation of the core–shell structure. Therefore, the Dy concentration in the thin Dy-substituted shell is important for improving the coercivity via the GBD process.

Journal

• MATERIALS TRANSACTIONS

  MATERIALS TRANSACTIONS 61 (3), 438-443, 2020-03-01

  The Japan Institute of Metals and Materials

Keywords

• neodymium magnet
• sintered magnet
• coercivity
• microstructure
• scanning transmission electron microscopy
• energy-dispersive X-ray spectrometry

Details

• CRID: 1390565134830847232
• NII Article ID: 130007801649
• NII Book ID: AA1151294X
• DOI: 10.2320/matertrans.mt-m2019265
• ISSN: 13475320
• ISSN: 13459678
• NDL BIB ID: 030275355
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I030275355
• Web Site: https://www.jstage.jst.go.jp/article/matertrans/61/3/61_MT-M2019265/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed