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：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：US10755840B2

公开(公告)日：2020-08-25

申请号：US15967893

申请日：2018-05-01

Applicant: TDK CORPORATION

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

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

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：US10748683B2

公开(公告)日：2020-08-18

申请号：US15285178

申请日：2016-10-04

Applicant: TDK CORPORATION

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

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

Abstract: 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：US20200321151A1

公开(公告)日：2020-10-08

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 ,  H01F41/02 ,  C22C38/00 ,  C22C38/06 ,  C22C38/16 ,  C22C38/14 ,  C22C38/10 ,  B22F3/16 ,  B22F9/04 ,  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：US09991035B2

公开(公告)日：2018-06-05

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 %.