Coercivity Enhancement by the Grain Boundary Diffusion Process to Nd-Fe-B Sintered Magnets

K. Hirota; H. Nakamura; T. Minowa; M. Honshima

doi:10.1109/TMAG.2006.879906

Coercivity Enhancement by the Grain Boundary Diffusion Process to Nd-Fe-B Sintered Magnets

K. Hirota, H. Nakamura, T. Minowa, M. Honshima

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

208 Citations (Scopus)

Abstract

Changes in magnetic properties after applying grain boundary diffusion process to Nd-Fe-B sintered magnets with a thickness of several millimeters were investigated, and their microstructures were also observed. Coercivities of the magnets coated with heavy rare earths (HRE=Dy and Tb) oxide or fluoride powder and then heat-treated, were enhanced significantly without a considerable reduction in a remanence. During the heat treatment, HRE element diffused into the magnet through the grain boundary, and formed HRE-rich shells around the grain boundary of the Nd₂Fe₁₄B phase by substituting Nd. The coercivity increased by more than 400 kA/m with a thickness of up to 3 mm for the magnet processed with TbF₃.

Original language	English
Pages (from-to)	2909-2911
Number of pages	3
Journal	IEEE Transactions on Magnetics
Volume	42
Issue number	10
DOIs	https://doi.org/10.1109/TMAG.2006.879906
Publication status	Published - 2006 Oct
Externally published	Yes

Keywords

Coercive force
Dy2O3
DyF3
TbF3
diffusion
grain boundary
powder

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

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AU - Hirota, K.

AU - Nakamura, H.

AU - Minowa, T.

AU - Honshima, M.

PY - 2006/10

Y1 - 2006/10

N2 - Changes in magnetic properties after applying grain boundary diffusion process to Nd-Fe-B sintered magnets with a thickness of several millimeters were investigated, and their microstructures were also observed. Coercivities of the magnets coated with heavy rare earths (HRE=Dy and Tb) oxide or fluoride powder and then heat-treated, were enhanced significantly without a considerable reduction in a remanence. During the heat treatment, HRE element diffused into the magnet through the grain boundary, and formed HRE-rich shells around the grain boundary of the Nd2Fe14B phase by substituting Nd. The coercivity increased by more than 400 kA/m with a thickness of up to 3 mm for the magnet processed with TbF3.

AB - Changes in magnetic properties after applying grain boundary diffusion process to Nd-Fe-B sintered magnets with a thickness of several millimeters were investigated, and their microstructures were also observed. Coercivities of the magnets coated with heavy rare earths (HRE=Dy and Tb) oxide or fluoride powder and then heat-treated, were enhanced significantly without a considerable reduction in a remanence. During the heat treatment, HRE element diffused into the magnet through the grain boundary, and formed HRE-rich shells around the grain boundary of the Nd2Fe14B phase by substituting Nd. The coercivity increased by more than 400 kA/m with a thickness of up to 3 mm for the magnet processed with TbF3.

KW - Coercive force

KW - Dy2O3

KW - DyF3

KW - TbF3

KW - diffusion

KW - grain boundary

KW - powder

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Coercivity Enhancement by the Grain Boundary Diffusion Process to Nd-Fe-B Sintered Magnets

Abstract

Keywords

ASJC Scopus subject areas

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