公开(公告)号：US11469016B2

公开(公告)日：2022-10-11

申请号：US16909351

申请日：2020-06-23

申请人： TDK Corporation

发明人： Ayato Kakoki ,  Makoto Iwasaki ,  Tetsuya Hidaka ,  Takuma Hayakawa

IPC分类号： H01F1/057 ,  B22F9/04 ,  H01F41/02 ,  C22C38/00 ,  C22C38/06 ,  C22C38/16 ,  C22C38/14 ,  C22C38/10 ,  B22F3/16 ,  C22C28/00 ,  C22C30/02

摘要： An R-T-B based sintered magnet containing a first heavy rare earth element, in which R includes Nd, T includes Co and Fe, the first heavy rare earth element includes Tb or Dy, the R-T-B based sintered magnet has a region in which a concentration of the first heavy rare earth element decreases from the surface toward the inside, a first grain boundary phase which contains the first heavy rare earth element and Nd but does not contain Co is present in one cross section including the region, and an area occupied by the first grain boundary phase in one cross section including the region is 1.8% or less.

公开(公告)号：US10530198B2

公开(公告)日：2020-01-07

申请号：US15258589

申请日：2016-09-07

申请人： TDK CORPORATION

发明人： Naoto Tsukamoto ,  Hiroshi Miyasaka ,  Makoto Iwasaki ,  Takahiro Kawashima ,  Chikara Ishizaka

IPC分类号： H02K1/02

摘要： An R-T-B based sintered magnet includes a first main surface and a first side surface. The first main surface has a coercivity that is higher than that of the first side surface. ΔHcjM≤60 kA/m is satisfied, where ΔHcjM is a difference in coercivity between a portion having a highest coercivity on the first main surface and a portion having a lowest coercivity on the first main surface. ΔHcjG≤60 kA/m is satisfied, where ΔHcjG is a difference in coercivity between a portion having a highest coercivity on a first cross section and a portion having a lowest coercivity on the first cross section and the first cross section is a cross section parallel to the first main surface and spaced from the first main surface at a predetermined length or more.

公开(公告)号：US10964463B2

公开(公告)日：2021-03-30

申请号：US15936752

申请日：2018-03-27

申请人： TDK CORPORATION

发明人： Takuma Hayakawa ,  Makoto Iwasaki ,  Tetsuya Hidaka ,  Eiji Kato ,  Hidetake Kitaoka

IPC分类号： H01F1/057 ,  H01F41/02 ,  B22F3/16 ,  B22F9/04 ,  C22C38/00

摘要： Provided is an alloy for R-T-B based rare earth magnet. “R” is one or more of a rare earth element, ‘T’ is one or more of a transition metal element essentially including Fe or Fe and Co, and “B” is boron. The alloy includes a single or a plural number of main phase (A), having a minimum length of 10 μm or more and a maximum length of 30 μm or more and 300 μm or less, in a cross section cut along a thickness direction of the alloy. The main phase (A) includes an R2T14B phase, and an area ratio of the main phase (A) to an entire cross section is 2% or more and 60% or less.

公开(公告)号：US20140335268A1

公开(公告)日：2014-11-13

申请号：US14340957

申请日：2014-07-25

申请人： TDK Corporation

发明人： Satoshi Tanaka ,  Fumitaka Baba ,  Makoto Iwasaki ,  Chikara Ishizaka

IPC分类号： H01F41/02 ,  H01F41/00

CPC分类号： H01F41/0293 ,  B22F2207/01 ,  B60L50/61 ,  B60L2220/14 ,  B60L2220/16 ,  B60L2220/50 ,  C22C38/002 ,  C22C38/005 ,  H01F1/0577 ,  H01F41/005 ,  H02K1/02 ,  H02K1/04 ,  H02K1/276 ,  Y02T10/6217 ,  Y02T10/641 ,  Y02T10/7077 ,  Y10T428/32

摘要： A rare earth sintered magnet 10 including a magnet body that includes a rare earth compound, and a protective layer on the magnet body, having a first layer and a second layer in that order from the magnet body side, wherein the surface portion of the magnet body has a higher heavy rare earth element content than the interior of the magnet body that is surrounded by the surface portion, the first layer includes a rare earth oxide, the mass ratio of the heavy rare earth element being 1 or greater with respect to the light rare earth element, and the second layer includes an oxide containing iron and/or boron which is different from the rare earth oxide, the second layer having a lower rare earth oxide content than the first layer.

摘要翻译： 包括稀土类化合物的磁体和磁铁体上的保护层的稀土类烧结磁体10具有从磁铁体侧依次的第一层和第二层，其中磁体的表面部分 本体具有比由表面部包围的磁体的内部更高的重稀土元素含量，第一层包括稀土类氧化物，重稀土类元素的质量比相对于 轻稀土元素，第二层包括与稀土氧化物不同的含有铁和/或硼的氧化物，第二层具有比第一层低的稀土氧化物含量。

公开(公告)号：US11387024B2

公开(公告)日：2022-07-12

申请号：US17207950

申请日：2021-03-22

申请人： TDK CORPORATION

发明人： Hiroki Kawamura ,  Makoto Iwasaki

IPC分类号： H01F1/057 ,  C22C38/16 ,  C22C38/14 ,  C22C38/06 ,  C22C38/00 ,  C22C38/10 ,  C22C30/02 ,  H01F41/02

摘要： An R—T—B based rare earth sintered magnet in which R is a rare earth sintered magnet, T is an iron group element, and B is boron. R includes one or more selected from Nd and Pr. The R—T—B based rare earth sintered magnet includes M and C in which M is one ore more selected from Zr, Ti, and Nb. The R—T—B based rare earth sintered magnet includes main phase grains and grain boundaries, and the grain boundaries includes a coexisting part in which a M—C compound, a M—B compound, and a 6-13-1 phase coexist. The R—T—B based rare earth sintered magnet attains improved HcJ while maintaining good Br and Hk/HcJ.

公开(公告)号：US10755840B2

公开(公告)日：2020-08-25

申请号：US15967893

申请日：2018-05-01

申请人： TDK CORPORATION

发明人： Tetsuya Hidaka ,  Takuma Hayakawa ,  Makoto Iwasaki ,  Ayato Kakoki

IPC分类号： H01F1/057 ,  H01F41/02 ,  C22C38/00 ,  B22F1/00 ,  C22C38/04 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  H01F1/058

摘要： An R-T-B based sintered magnet includes “R”, “T”, and “B”. “R” represents a rare earth element. “T” represents a metal element other than rare earth elements including at least Fe, Cu, Mn, Al, Co, Ga, and Zr. “B” represents boron or boron and carbon. With respect to 100 mass % of a total mass of the R-T-B based sintered magnet, a content of “R” is 28.0 to 31.5 mass %, a content of Cu is 0.04 to 0.50 mass %, a content of Mn is 0.02 to 0.10 mass %, a content of Al is 0.15 to 0.30 mass %, a content of Co is 0.50 to 3.0 mass %, a content of Ga is 0.08 to 0.30 mass %, a content of Zr is 0.10 to 0.25 mass %, and a content of “B” is 0.85 to 1.0 mass %.

公开(公告)号：US10748683B2

公开(公告)日：2020-08-18

申请号：US15285178

申请日：2016-10-04

申请人： TDK CORPORATION

发明人： Tetsuya Hidaka ,  Takuma Hayakawa ,  Makoto Iwasaki ,  Ayato Kakoki ,  Naoto Tsukamoto ,  Fumitaka Baba

IPC分类号： H01F41/02 ,  H01F1/053 ,  H01F1/057 ,  B22F3/24 ,  C22C38/12 ,  C22C38/16 ,  C22C33/02 ,  C22C38/14 ,  C22C38/00 ,  C22C38/06 ,  C22C38/10 ,  C22C28/00

摘要： An R-T-B based sintered magnet includes “R”, “T”, and “B”. “R” represents a rare earth element including at least Tb. “T” represents a metal element except rare earth elements including at least Fe, Cu, Mn, Al, and Co. “B” represents boron or boron and carbon. With respect to 100 mass % of a total mass of the R-T-B based sintered magnet, a content of “R” is 28.0 to 32.0 mass %, a content of Cu is 0.04 to 0.50 mass %, a content of Mn is 0.02 to 0.10 mass %, a content of Al is 0.15 to 0.30 mass %, a content of Co is 0.50 to 3.0 mass %, and a content of “B” is 0.85 to 1.0 mass %. Tb2/Tb1 is 0.40 to less than 1.0, where Tb1 and Tb2 (mass %) denote a content of Tb at a surface portion and at a core portion, respectively.

公开(公告)号：US10523101B2

公开(公告)日：2019-12-31

申请号：US15608067

申请日：2017-05-30

申请人： TDK CORPORATION

发明人： Makoto Iwasaki ,  Fumitaka Baba ,  Chikara Ishizaka

IPC分类号： H02K41/03 ,  H02P29/66 ,  H02K1/27 ,  H02P21/22 ,  H02P27/04

摘要： A motor includes a magnet and a coil. α2=[{(Br2−Br1)/Br1}/(T2−T1)]×100≥−0.10 and α3=[{(Br3−Br1)/Br1}/(T3−T1)]×100≤−0.12 are satisfied. In the magnet, Br1 (mT) is a residual magnetic flux density at T1 (° C.), Br2 (mT) is a residual magnetic flux density at T2 (° C.), and Br3 (mT) is a residual magnetic flux density at T3 (° C.), and α2 (%/° C.) is a temperature coefficient at a target temperature of T2 (° C.) with respect to a reference temperature of T1 (° C.), and α3 (%/° C.) is a temperature coefficient at a target temperature of T3 (° C.) with respect to a reference temperature of T1 (° C.) in conditions of T1=23, T2=60, and T3=180.

公开(公告)号：US11492684B2

公开(公告)日：2022-11-08

申请号：US16295420

申请日：2019-03-07

申请人： TDK CORPORATION

发明人： Makoto Iwasaki

IPC分类号： C22C30/00 ,  H01F1/057 ,  H01F41/02 ,  B22F3/24 ,  B22F9/04 ,  B22F3/16

摘要： An R-T-B based permanent magnet, in which R is a rare earth element, T is Fe or a combination of Fe and Co, and B is boron, includes main phase grains made of an R2T14B crystal phase and grain boundaries formed between the main phase grains. The grain boundaries include an R—O—C—N concentrated part having higher concentrations of R, O, C, and N than that of the main phase grains. The R—O—C—N concentrated part includes a heavy rare earth element. The R—O—C—N concentrated part has a core part and a shell part covering at least part of the core part. A concentration of the heavy rare earth element in the shell part is higher than a concentration of the heavy element in the core part. A covering ratio of the shell part with respect to the core part of the R—O—C—N concentrated part is 45% or more in average.

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

IPC分类号： H01F1/057 ,  C22C30/02

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.