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
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/1
Y1 - 2012/1
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 - https://www.scopus.com/pages/publications/84857519766
UR - https://www.scopus.com/inward/citedby.url?scp=84857519766&partnerID=8YFLogxK
U2 - 10.2320/jinstmet.76.17
DO - 10.2320/jinstmet.76.17
M3 - Article
AN - SCOPUS:84857519766
SN - 0021-4876
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
IS - 1
ER -