公开(公告)号：US11469016B2

公开(公告)日：2022-10-11

申请号：US16909351

申请日：2020-06-23

Applicant: TDK Corporation

Inventor： Ayato Kakoki ,  Makoto Iwasaki ,  Tetsuya Hidaka ,  Takuma Hayakawa

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

Abstract: 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

Applicant: TDK CORPORATION

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

IPC: H02K1/02

Abstract: 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

Applicant: TDK CORPORATION

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

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

Abstract: 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

Applicant: TDK Corporation

Inventor： Satoshi Tanaka ,  Fumitaka Baba ,  Makoto Iwasaki ,  Chikara Ishizaka

IPC: H01F41/02 ,  H01F41/00

CPC classification number: 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

Abstract: 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.

Abstract translation: 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：US11492684B2

公开(公告)日：2022-11-08

申请号：US16295420

申请日：2019-03-07

Applicant: TDK CORPORATION

Inventor： Makoto Iwasaki

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

Abstract: 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

Applicant: TDK Corporation

Inventor： Mariko Fujiwara ,  Makoto Iwasaki

IPC: H01F1/057 ,  C22C30/02

Abstract: 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.

公开(公告)号：US10991492B2

公开(公告)日：2021-04-27

申请号：US16823487

申请日：2020-03-19

Applicant: TDK CORPORATION

Inventor： Mariko Fujiwara ,  Makoto Iwasaki

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.

公开(公告)号：US10242777B2

公开(公告)日：2019-03-26

申请号：US15420151

申请日：2017-01-31

Applicant: TDK Corporation

Inventor： Makoto Iwasaki ,  Tetsuya Hidaka ,  Takuma Hayakawa ,  Ayato Kakoki ,  Yoshinori Fujikawa ,  Syota Goto ,  Haruna Nakajima ,  Takeshi Masuda ,  Chikara Ishizaka

IPC: H01F1/055 ,  B22F1/00 ,  B22F3/10 ,  B22F9/02 ,  C22C38/00 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  H01F1/057 ,  H01F41/02 ,  B22F9/04 ,  C22C33/02

Abstract: Provided is a sintered magnet that is an R-T-B based sintered magnet having a region having a concentration of at least one heavy rare earth element decreasing from the surface toward the inside, in which the at least one heavy rare earth element includes at least either of Tb or Dy, R includes Nd, T includes Fe, Co, and Cu, there is a grain boundary phase containing at least either of Tb or Dy and Nd between two main phase particles, and a value obtained by subtracting a half value width of a concentration distribution curve of Cu from a half value width of a concentration distribution curve of Tb or Dy in a part including the grain boundary phase is from 10 to 20 nm.

公开(公告)号：US10026532B2

公开(公告)日：2018-07-17

申请号：US15285113

申请日：2016-10-04

Applicant: TDK CORPORATION

Inventor： Tetsuya Hidaka ,  Takuma Hayakawa ,  Makoto Iwasaki ,  Ayato Kakoki

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

Abstract: 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：US11783973B2

公开(公告)日：2023-10-10

申请号：US16291950

申请日：2019-03-04

Applicant: TDK CORPORATION

Inventor： Hidetake Kitaoka ,  Makoto Iwasaki

IPC: H01F1/057 ,  C22C38/16 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00 ,  B22F9/04 ,  B22F3/10

CPC classification number: H01F1/0577 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/16 ,  B22F3/10 ,  B22F9/04 ,  B22F2009/044 ,  B22F2301/355 ,  C22C2202/02

Abstract: 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, B is boron, and further includes M. The R-T-B based permanent magnet includes main phase grains consisting of R2T14B phase. M at least includes Ga and Zr. The R-T-B based permanent magnet further includes C and O. R content is 29.0 mass % to 33.0 mass %, B content is 0.85 mass % to 1.05 mass %, Ga content is 0.30 mass % to 1.20 mass %, 0 content is 0.03 mass % to 0.20 mass %, and C content is 0.03 mass % to 0.30 mass %. Further, the R-T-B based permanent magnet satisfies 3.48m(B)−2.67≤m(Zr)≤3.48m(B)−1.87 in which m(B) (mass %) is B content and m(Zr) (mass %) is Zr content.