Dy gradient and coercivity in grain boundary diffusion processed Nd-Fe-B magnet

By controlling Dy vapor deposition process, the amount of Dy that diffused into the magnet was increased gradually from 0.1 wt.% to 0.3 wt.%. Compared with the original status, the coercivity increment was not proportional to the Dy diffusion amount. Subsequent H（cj） and Dy content gradient data sho...

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Bibliographic Details
Published inJournal of rare earths Vol. 35; no. 6; pp. 559 - 566
Main Author 周磊 李建 程星华 刘涛 喻晓军 李波
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.06.2017
Subjects
coercivity
Dy content
grain boundary diffusion process
Nd-Fe-B sintered magnet
rare earths
Dy content
coercivity
grain boundary diffusion process
Nd-Fe-B sintered magnet
rare earths
Online AccessGet full text
ISSN1002-0721
2509-4963
DOI10.1016/S1002-0721(17)60948-7

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Summary:By controlling Dy vapor deposition process, the amount of Dy that diffused into the magnet was increased gradually from 0.1 wt.% to 0.3 wt.%. Compared with the original status, the coercivity increment was not proportional to the Dy diffusion amount. Subsequent H（cj） and Dy content gradient data showed that slope of the 0.3 wt.% sample gradient was bigger than that of 0.1 wt.% one, and the gaps between outer flakes and inner flakes enlarged with the increasement of Dy diffusion amount. Although Dy mostly enriched in triple-junction regions in electron-probe microscope analysis（EPMA） images, the following Auger depth graph showed that Dy content was as high as 3.0 at.% in 1.5 mm deep center. It proved that Dy tended to get into the main phase rather than stayed in the grain boundary during the diffusion process, and over-diffusion of Dy in the main phase was unhelpful for the coercivity enhancement.
Bibliography:ZHOU Lei1, LI Jian1,2, CHENG Xinghua1, LIU Tao1, YU Xiaojun1, LI Bo2 （1. Functional Materials Division, Advanced Technology ＆ Materials Co., Ltd., Beijing 101318, China; 2. China Iron ＆ Steel Research Institute Group, Beijing 100081, China）
11-2788/TF
coercivity magnet processed junction enriched triple outer flake stayed mostly
By controlling Dy vapor deposition process, the amount of Dy that diffused into the magnet was increased gradually from 0.1 wt.% to 0.3 wt.%. Compared with the original status, the coercivity increment was not proportional to the Dy diffusion amount. Subsequent H（cj） and Dy content gradient data showed that slope of the 0.3 wt.% sample gradient was bigger than that of 0.1 wt.% one, and the gaps between outer flakes and inner flakes enlarged with the increasement of Dy diffusion amount. Although Dy mostly enriched in triple-junction regions in electron-probe microscope analysis（EPMA） images, the following Auger depth graph showed that Dy content was as high as 3.0 at.% in 1.5 mm deep center. It proved that Dy tended to get into the main phase rather than stayed in the grain boundary during the diffusion process, and over-diffusion of Dy in the main phase was unhelpful for the coercivity enhancement.
ISSN:1002-0721
2509-4963
DOI:10.1016/S1002-0721(17)60948-7