Title:
R-T-B BASED PERMANENT MAGNET
Document Type and Number:
WIPO Patent Application WO/2021/107011
Kind Code:
A1
Abstract:
[Problem] To provide an R-T-B based permanent magnet which has high coercivity Hcj and high residual magnetic flux density Br at room temperature, while having excellent coercivity Hcj and excellent temperature characteristics at high temperatures.
[Solution] An R-T-B based permanent magnet which contains R2T14B main phase crystal grains and a grain boundary. Meanwhile, R represents one or more rare earth elements; T represents Fe or one or more iron group elements necessarily including Fe and Co; and B represents boron. In a cross-section that is parallel to the orientation direction of the R-T-B based permanent magnet, the area ratio of the R2T14B main phase crystal grains in the R-T-B based permanent magnet is 92.0% or more. The grain boundary contains an R-OCN phase. The volume ratio of the R-OCN phase in the grain boundary is 34.0% or less. The R-T-B based permanent magnet additionally contains O. The O content in the R-T-B based permanent magnet is less than 900 ppm.
Inventors:
FUJIKAWA YOSHINORI (JP)
WATANABE TAKASHI (JP)
KODA ATSUSHI (JP)
JINGU MIKA (JP)
WATANABE TAKASHI (JP)
KODA ATSUSHI (JP)
JINGU MIKA (JP)
Application Number:
PCT/JP2020/044023
Publication Date:
June 03, 2021
Filing Date:
November 26, 2020
Export Citation:
Assignee:
TDK CORP (JP)
International Classes:
H01F41/02; H01F1/057
Foreign References:
| JP2007266026A | 2007-10-11 | |||
| JP2007059619A | 2007-03-08 |
Attorney, Agent or Firm:
MAEDA & SUZUKI (JP)
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