Invention Grant
- Patent Title: R-T-B based permanent magnet
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Application No.: US16823487Application Date: 2020-03-19
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Publication No.: US10991492B2Publication Date: 2021-04-27
- Inventor: Mariko Fujiwara , Makoto Iwasaki
- Applicant: TDK CORPORATION
- Applicant Address: JP Tokyo
- Assignee: TDK CORPORATION
- Current Assignee: TDK CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Oliff PLC
- Priority: JPJP2019-053644 20190320
- Main IPC: C22C38/16
- IPC: C22C38/16 ; C22C38/14 ; C22C38/10 ; C22C38/00 ; C22C38/06 ; H01F1/057 ; B22F3/24

Abstract:
The present invention provides an R-T-B based permanent magnet capable of improving a coercive force HcJ while maintaining a residual magnetic flux density Br.
The R-T-B based permanent magnet includes Ga. R is one or more selected from rare earth elements, T is Fe or a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet has main phase grains including a crystal grain having an R2T14B crystal structure and grain boundaries formed between adjacent two or more main phase grains, and 0.030≤[Ga]/[R]≤0.100 is satisfied in which [Ga] represents an atomic concentration of Ga and [R] represents an atomic concentration of R in the main phase grains.
The R-T-B based permanent magnet includes Ga. R is one or more selected from rare earth elements, T is Fe or a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet has main phase grains including a crystal grain having an R2T14B crystal structure and grain boundaries formed between adjacent two or more main phase grains, and 0.030≤[Ga]/[R]≤0.100 is satisfied in which [Ga] represents an atomic concentration of Ga and [R] represents an atomic concentration of R in the main phase grains.
Public/Granted literature
- US20200303098A1 R-T-B BASED PERMANENT MAGNET Public/Granted day:2020-09-24
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