Nano-Dimensional analysis of high-performance Nd-Fe-B-Based magnetic materials for micro-structural control

Masaru Itakura, Noriyuki Kuwano

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Changes in microstructure of Nd-Fe-B based magnetic materials were investigated with advanced electron microscopes to study the Tb diffusion treatment for high coercivity for sintered magnets and the hydrogenation- decomposition-desorption- recombination (HDDR) process for high anistropic magnet powders. In sintered magnets, it was found that morphology of a Nd- rich wetting-layer phase changes to be continuous in shape and uniform in thickness in association with diffusion of Tb. The formation of the continuous Nd-rich wetting-layer phase containing a small amount of Tb leads to an effective increase in coercivity. In the HDDR magnet powder, a recombined Nd 2Fe 14B phase is formed first as a rim phase on spherical NdH 2 grains during the DR-process. Small grain size of NdH 2 phase and large grain size of a-Fe matrix after the HD-process can produce small grains of highly aligned Nd 2Fe 14B that lead to high remanence and high coercivity. These results indicate that a nano-dimensional analysis is essentially important to develop the high-performance of magnetic materials.

Original languageEnglish
Pages (from-to)17-26
Number of pages10
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume76
Issue number1
DOIs
Publication statusPublished - Jan 1 2012

Fingerprint

Magnetic materials
dimensional analysis
magnetic materials
Magnets
magnets
Coercive force
coercivity
Powders
Hydrogenation
hydrogenation
wetting
Wetting
Desorption
Direct reduction process
grain size
desorption
Decomposition
decomposition
Remanence
remanence

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Materials Chemistry
  • Metals and Alloys
  • Condensed Matter Physics

Cite this

@article{ccc12067c66643258005d9add68616da,
title = "Nano-Dimensional analysis of high-performance Nd-Fe-B-Based magnetic materials for micro-structural control",
abstract = "Changes in microstructure of Nd-Fe-B based magnetic materials were investigated with advanced electron microscopes to study the Tb diffusion treatment for high coercivity for sintered magnets and the hydrogenation- decomposition-desorption- recombination (HDDR) process for high anistropic magnet powders. In sintered magnets, it was found that morphology of a Nd- rich wetting-layer phase changes to be continuous in shape and uniform in thickness in association with diffusion of Tb. The formation of the continuous Nd-rich wetting-layer phase containing a small amount of Tb leads to an effective increase in coercivity. In the HDDR magnet powder, a recombined Nd 2Fe 14B phase is formed first as a rim phase on spherical NdH 2 grains during the DR-process. Small grain size of NdH 2 phase and large grain size of a-Fe matrix after the HD-process can produce small grains of highly aligned Nd 2Fe 14B that lead to high remanence and high coercivity. These results indicate that a nano-dimensional analysis is essentially important to develop the high-performance of magnetic materials.",
author = "Masaru Itakura and Noriyuki Kuwano",
year = "2012",
month = "1",
day = "1",
doi = "10.2320/jinstmet.76.17",
language = "English",
volume = "76",
pages = "17--26",
journal = "Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals",
issn = "0021-4876",
publisher = "公益社団法人 日本金属学会",
number = "1",

}

TY - JOUR

T1 - Nano-Dimensional analysis of high-performance Nd-Fe-B-Based magnetic materials for micro-structural control

AU - Itakura, Masaru

AU - Kuwano, Noriyuki

PY - 2012/1/1

Y1 - 2012/1/1

N2 - Changes in microstructure of Nd-Fe-B based magnetic materials were investigated with advanced electron microscopes to study the Tb diffusion treatment for high coercivity for sintered magnets and the hydrogenation- decomposition-desorption- recombination (HDDR) process for high anistropic magnet powders. In sintered magnets, it was found that morphology of a Nd- rich wetting-layer phase changes to be continuous in shape and uniform in thickness in association with diffusion of Tb. The formation of the continuous Nd-rich wetting-layer phase containing a small amount of Tb leads to an effective increase in coercivity. In the HDDR magnet powder, a recombined Nd 2Fe 14B phase is formed first as a rim phase on spherical NdH 2 grains during the DR-process. Small grain size of NdH 2 phase and large grain size of a-Fe matrix after the HD-process can produce small grains of highly aligned Nd 2Fe 14B that lead to high remanence and high coercivity. These results indicate that a nano-dimensional analysis is essentially important to develop the high-performance of magnetic materials.

AB - Changes in microstructure of Nd-Fe-B based magnetic materials were investigated with advanced electron microscopes to study the Tb diffusion treatment for high coercivity for sintered magnets and the hydrogenation- decomposition-desorption- recombination (HDDR) process for high anistropic magnet powders. In sintered magnets, it was found that morphology of a Nd- rich wetting-layer phase changes to be continuous in shape and uniform in thickness in association with diffusion of Tb. The formation of the continuous Nd-rich wetting-layer phase containing a small amount of Tb leads to an effective increase in coercivity. In the HDDR magnet powder, a recombined Nd 2Fe 14B phase is formed first as a rim phase on spherical NdH 2 grains during the DR-process. Small grain size of NdH 2 phase and large grain size of a-Fe matrix after the HD-process can produce small grains of highly aligned Nd 2Fe 14B that lead to high remanence and high coercivity. These results indicate that a nano-dimensional analysis is essentially important to develop the high-performance of magnetic materials.

UR - http://www.scopus.com/inward/record.url?scp=84857519766&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84857519766&partnerID=8YFLogxK

U2 - 10.2320/jinstmet.76.17

DO - 10.2320/jinstmet.76.17

M3 - Article

VL - 76

SP - 17

EP - 26

JO - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals

JF - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals

SN - 0021-4876

IS - 1

ER -