CORE-SHELL STRUCTURE R-T-B RARE EARTH PERMANENT MAGNET HAVING GD-RICH CORE FOR USE IN HIGH-TEMPERATURE ENVIRONMENT AND PREPARATION METHOD THEREFOR

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)

Application Number:

PCT/CN2023/096203

Publication Date:

April 18, 2024

Filing Date:

May 25, 2023

Export Citation:

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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)

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