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

Masaru Itakura, Noriyuki Kuwano

Research output: Contribution to journalArticlepeer-review

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 2012

All Science Journal Classification (ASJC) codes

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

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