Title:
HIGH-COERCIVITY HIGH-RESISTIVITY NEODYMIUM-IRON-BORON PERMANENT MAGNET AND PREPARATION METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2022/213491
Kind Code:
A1
Abstract:
Disclosed are a high-coercivity high-resistivity neodymium-iron-boron permanent magnet and a preparation method therefor. According to the method, a powder slurry comprising a heavy rare earth compound, an oxide and/or a carbide is sprayed on sheet-like neodymium-iron-boron magnet blanks treated by means of a surface cleaning process, and then the magnets are superimposed and then subject to a three-stage heat treatment to obtain a high-coercivity high-resistivity neodymium-iron-boron permanent magnet. The heavy rare earth penetrates into the interior of the sheet-like magnets at a high temperature, thereby improving the coercivity of the sheet-like magnets. However, the heavy rare earth element or alloy element as well as carbide powder or oxide powder, a portion of which does not penetrate into the sheet-like magnets, may form a spacer layer to bond two sheet-like magnets together. In addition, since the spacer layer contains a high proportion of non-conductive elements, such as oxygen elements or carbon elements, the resistivity of the whole magnet is improved. That is, the present invention simultaneously improves the coercivity and the resistivity of the neodymium-iron-boron magnet.
Inventors:
YAN CHANGJIANG (CN)
QIAN NIJIAN (CN)
WU ZHIGUO (CN)
QIAN NIJIAN (CN)
WU ZHIGUO (CN)
Application Number:
PCT/CN2021/103318
Publication Date:
October 13, 2022
Filing Date:
June 29, 2021
Export Citation:
Assignee:
NINGBO KETIAN MAGNET CO LTD (CN)
International Classes:
H01F41/02; H01F1/057
Foreign References:
| CN107958761A | 2018-04-24 | |||
| CN110911150A | 2020-03-24 | |||
| CN111477447A | 2020-07-31 | |||
| CN111326307A | 2020-06-23 | |||
| US4747874A | 1988-05-31 |
Attorney, Agent or Firm:
SHANGHAI SHENXIN LAW FIRM (CN)
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