Title:
CORE-SHELL STRUCTURE R-T-B RARE EARTH PERMANENT MAGNET HAVING GD-RICH CORE FOR USE IN HIGH-TEMPERATURE ENVIRONMENT AND PREPARATION METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2024/077966
Kind Code:
A1
Abstract:
The present invention provides a core-shell structure R-T-B rare earth permanent magnet having a Gd-rich core for use in a high-temperature environment. In the magnet, the rare earth element R content is 29.0-34.0 wt%, R consisting of Gd and R1, and the Gd content is 1.0-20.0 wt% of the mass of the magnet; the main phase crystal grains contain Gd-rich core and Gd-poor shell layers, a volume ratio thereof being 20-80 vol%. The present invention uses a double-alloy method to separately smelt alloy sheets having high Gd content and low Gd content, and then prepares a sintered magnet; elemental Gd in the high-Gd content main phase may diffuse to the grain boundary of an R-rich phase during high-temperature diffusion treatment, the high-Gd content main phase crystal grain ultimately forming a core-shell structure having a Gd-poor shell layer and a Gd-rich core; the Gd-poor shell layer can significantly reduce the degradation effect of elemental Gd element on the coercivity of the magnet, thereby fully utilizing the characteristics of Gd, and preparing a magnet having a low temperature coefficient and high coercivity. The grain boundary diffusion treatment of elemental Dy/Tb may further improve the coercivity of the magnet, to prepare an R-T-B rare earth permanent magnet suitable for higher working temperatures.
Inventors:
FU SONG (CN)
CHEN BIAO (CN)
WANG RONGJIE (CN)
ZHU XIAOHANG (CN)
ZHANG ZHAONENG (CN)
YANG XIAOLU (CN)
CHEN BIAO (CN)
WANG RONGJIE (CN)
ZHU XIAOHANG (CN)
ZHANG ZHAONENG (CN)
YANG XIAOLU (CN)
Application Number:
PCT/CN2023/096203
Publication Date:
April 18, 2024
Filing Date:
May 25, 2023
Export Citation:
Assignee:
ZHEJIANG INNUOVO MAGNETICS CO LTD (CN)
International Classes:
H01F1/057
Foreign References:
CN115938708A | 2023-04-07 | |||
CN108695032A | 2018-10-23 | |||
CN105895286A | 2016-08-24 | |||
CN105895287A | 2016-08-24 | |||
CN103996475A | 2014-08-20 | |||
JP2018174205A | 2018-11-08 |
Attorney, Agent or Firm:
HANGZHOU SIKERUI PATENT OFFICE CO., LTD (CN)
Download PDF: