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公开(公告)号：US11145444B2
公开(公告)日：2021-10-12
申请号：US16364443
申请日：2019-03-26
申请人： TDK Corporation
发明人： Mariko Fujiwara , Masashi Miwa
摘要： An R-T-B-based sintered magnet 2 contains a rare earth element R, a transition metal element T, B, Ga, and O, the sintered magnet 2 includes a magnet body 4 and an oxidized layer 6 covering the magnet body 4, the magnet body 4 includes main phase grains 8 containing a crystal of R2T14B and a grain boundary phase 1 positioned between the main phase grains 8 and containing R, the oxidized layer 6 includes a plurality of oxide phases 3A containing R, T, Ga, and O, the oxide phase 3A satisfies the following Formulas (1) and (2) regarding the content (unit: atom %) of each element, and the oxide phase 3A in the oxidized layer 6 covers the grain boundary phase 1 in the magnet body 4. 0.3≤[R]/[T]≤0.5 (1) 0.2≤[O]/([R]+[T]+[Ga]+[O])≤0.7 (2)
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公开(公告)号：US11244779B2
公开(公告)日：2022-02-08
申请号：US16823997
申请日：2020-03-19
申请人： TDK Corporation
发明人： Mariko Fujiwara , Makoto Iwasaki
摘要： The object of the present invention is to provide an R-T-B based permanent magnet having a wide temperature range suitable for sintering. The R-T-B based permanent magnet in which R is one or more rare earth elements, T is a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet comprises M, O, C, and N. M is three or more selected from Cu, Ga, Mn, Zr, and Al; and at least comprises Cu, Ga, and Zr. A content of each component is within a predetermined range. The R-T-B based permanent magnet includes main phase grains made of R2T14B compound and grain boundaries existing between main phase grains. The grain boundaries include a two-grain boundary which is a grain boundary formed between two adjacent main phase grains, and a Zr—B compound is included in the two-grain boundary.
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公开(公告)号：US10991492B2
公开(公告)日：2021-04-27
申请号：US16823487
申请日：2020-03-19
申请人： TDK CORPORATION
发明人： Mariko Fujiwara , Makoto Iwasaki
摘要： 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.
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