Microstructure of high coercivity Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment

N. Watanabe; M. Itakura; M. Nishida

doi:10.1016/j.jallcom.2012.12.084

Microstructure of high coercivity Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment

N. Watanabe, M. Itakura, M. Nishida

Materials Physics and Engineering

Research output: Contribution to journal › Article › peer-review

46 Citations (Scopus)

Abstract

Microstructure of Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment was investigated with high-resolution scanning electron microscopy (HRSEM), analytical transmission electron microscopy (ATEM) and high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). It was found that Dy diffuses along the thin grain boundary (GB) phase between Nd₂(Fe,Co)₁₄B grains, and then the Dy substitutes for a part of Nd near the surface of the Nd₂(Fe,Co)₁₄B grains. Consequently, two-layered-wrapping structure of thin GB phase and thin (Nd,Dy)₂(Fe,Co)₁₄B layer is formed on each Nd ₂(Fe,Co)₁₄B grain. Moreover, the Dy substitution occurs preferentially at the Nd-sites of a-planes compared with that of c-planes in the Nd₂(Fe,Co)₁₄B grains. These results indicate that the Dy diffusion treatment improves significantly the coercivity by forming the thin (Nd,Dy)₂(Fe,Co)₁₄B layer on the surface of Nd ₂(Fe,Co)₁₄B grains, although the treatment leads to grain growth and deterioration of the c-axis alignment of Nd₂(Fe,Co) ₁₄B grains.

Original language	English
Pages (from-to)	1-4
Number of pages	4
Journal	Journal of Alloys and Compounds
Volume	557
DOIs	https://doi.org/10.1016/j.jallcom.2012.12.084
Publication status	Published - Apr 25 2013

All Science Journal Classification (ASJC) codes

Mechanics of Materials
Mechanical Engineering
Metals and Alloys
Materials Chemistry

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10.1016/j.jallcom.2012.12.084

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title = "Microstructure of high coercivity Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment",

abstract = "Microstructure of Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment was investigated with high-resolution scanning electron microscopy (HRSEM), analytical transmission electron microscopy (ATEM) and high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). It was found that Dy diffuses along the thin grain boundary (GB) phase between Nd2(Fe,Co)14B grains, and then the Dy substitutes for a part of Nd near the surface of the Nd2(Fe,Co)14B grains. Consequently, two-layered-wrapping structure of thin GB phase and thin (Nd,Dy)2(Fe,Co)14B layer is formed on each Nd 2(Fe,Co)14B grain. Moreover, the Dy substitution occurs preferentially at the Nd-sites of a-planes compared with that of c-planes in the Nd2(Fe,Co)14B grains. These results indicate that the Dy diffusion treatment improves significantly the coercivity by forming the thin (Nd,Dy)2(Fe,Co)14B layer on the surface of Nd 2(Fe,Co)14B grains, although the treatment leads to grain growth and deterioration of the c-axis alignment of Nd2(Fe,Co) 14B grains.",

author = "N. Watanabe and M. Itakura and M. Nishida",

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AU - Itakura, M.

AU - Nishida, M.

PY - 2013/4/25

Y1 - 2013/4/25

N2 - Microstructure of Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment was investigated with high-resolution scanning electron microscopy (HRSEM), analytical transmission electron microscopy (ATEM) and high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). It was found that Dy diffuses along the thin grain boundary (GB) phase between Nd2(Fe,Co)14B grains, and then the Dy substitutes for a part of Nd near the surface of the Nd2(Fe,Co)14B grains. Consequently, two-layered-wrapping structure of thin GB phase and thin (Nd,Dy)2(Fe,Co)14B layer is formed on each Nd 2(Fe,Co)14B grain. Moreover, the Dy substitution occurs preferentially at the Nd-sites of a-planes compared with that of c-planes in the Nd2(Fe,Co)14B grains. These results indicate that the Dy diffusion treatment improves significantly the coercivity by forming the thin (Nd,Dy)2(Fe,Co)14B layer on the surface of Nd 2(Fe,Co)14B grains, although the treatment leads to grain growth and deterioration of the c-axis alignment of Nd2(Fe,Co) 14B grains.

AB - Microstructure of Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment was investigated with high-resolution scanning electron microscopy (HRSEM), analytical transmission electron microscopy (ATEM) and high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). It was found that Dy diffuses along the thin grain boundary (GB) phase between Nd2(Fe,Co)14B grains, and then the Dy substitutes for a part of Nd near the surface of the Nd2(Fe,Co)14B grains. Consequently, two-layered-wrapping structure of thin GB phase and thin (Nd,Dy)2(Fe,Co)14B layer is formed on each Nd 2(Fe,Co)14B grain. Moreover, the Dy substitution occurs preferentially at the Nd-sites of a-planes compared with that of c-planes in the Nd2(Fe,Co)14B grains. These results indicate that the Dy diffusion treatment improves significantly the coercivity by forming the thin (Nd,Dy)2(Fe,Co)14B layer on the surface of Nd 2(Fe,Co)14B grains, although the treatment leads to grain growth and deterioration of the c-axis alignment of Nd2(Fe,Co) 14B grains.

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Microstructure of high coercivity Nd-Fe-Co-Ga-B hot-deformed magnet improved by the Dy diffusion treatment

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