公开(公告)号：US20200299813A1

公开(公告)日：2020-09-24

申请号：US16824218

申请日：2020-03-19

Applicant: TDK CORPORATION

Inventor： Taeko Tsubokura ,  Takeshi Masuda

IPC: C22C28/00 ,  H01F1/057

Abstract: The present invention provides an R-T-B based permanent magnet having excellent magnetic properties and corrosion resistance even when Co content is small.The R-T-B based permanent magnet in which R is a rare earth element including one or more selected from Nd and Pr and one or more selected from Dy and Tb, T is a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet further includes Zr. A total content of Nd, Pr, Dy, and Tb is 30.00 mass % to 32.20 mass %, Co content is 0.30 mass % to 1.30 mass %, Zr content is 0.21 mass % to 0.85 mass %, and B content is 0.90 mass % to 1.02 mass % with respect to 100 mass % of the R-T-B based permanent magnet.

公开(公告)号：US20200303100A1

公开(公告)日：2020-09-24

申请号：US16823456

申请日：2020-03-19

Applicant: TDK CORPORATION

Inventor： Taeko Tsubokura ,  Takeshi Masuda

IPC: H01F1/055 ,  C22C38/06 ,  C22C38/00 ,  C22C38/10

Abstract: To provide an R-T-B based permanent magnet having excellent magnet properties and corrosion resistance even in case Co content is too small, and also to provide R-T-B based permanent magnet suitable for a grain boundary diffusion.The R-T-B based permanent magnet in which R represents a rare earth element including at least one selected from Nd, Pr, Dy, and Tb, T represents a combination of Fe and Co, and B represents boron. The R-T-B based permanent magnet further includes Zr. A total content of Nd, Pr, Dy, and Tb is 29.5 mass % to 31.5 mass %, Co content is 0.35 mass % to 1.50 mass %, Zr content is 0.21 mass % to 0.85 mass %, B content is 0.90 mass % to 1.02 mass % with respect to 100 mass % of the R-T-B based permanent magnet.

公开(公告)号：US20200176184A1

公开(公告)日：2020-06-04

申请号：US16698083

申请日：2019-11-27

Applicant: TDK Corporation

Inventor： Taeko TSUBOKURA ,  Takeshi Masuda ,  Taku Murase

IPC: H01F41/02 ,  H01F1/057 ,  C23C10/30 ,  C22C28/00 ,  C22C30/02

Abstract: A method for manufacturing an R-T-B permanent magnet comprises a diffusion step of adhering a diffusing material to the surface of a magnet base material and heating the magnet base material with the diffusing material adhered thereto, wherein the magnet base material comprises rare-earth elements R, transition metal elements T and boron B; at least some of R are Nd; at least some of T are Fe; the diffusing material comprises a first component, a second component and a third component; the first component is at least one of a simple substance of Tb and a simple substance of Dy; the second component comprises a metal comprising at least one of Nd and Pr and not comprising Tb and Dy; and the third component is at least one selected from the group consisting of a simple substance of Cu, an alloy comprising Cu, and a compound of Cu.

公开(公告)号：US11335483B2

公开(公告)日：2022-05-17

申请号：US16159764

申请日：2018-10-15

Applicant: TDK Corporation

Inventor： Taeko Tsubokura ,  Takeshi Masuda ,  Toshihiro Kuroshima

IPC: H01F1/057 ,  C22C28/00

Abstract: The present invention provides a magnet structure comprising a first magnet, a second magnet, and an intermediate layer joining the first magnet and the second magnet. In the magnet structure, each of the first magnet and the second magnet is a permanent magnet comprising a rare earth element R, a transition metal element T, and boron B. In addition, the rare earth element R comprises: a light rare earth element RL comprising at least Nd; and a heavy rare earth element RH, and the transition metal element T comprises Fe, Co, and Cu. Further, the intermediate layer comprises: an RL oxide phase comprising an oxide of the light rare earth element RL; and an RL—Co—Cu phase comprising the light rare element RL, Co, and Cu.

公开(公告)号：US11244777B2

公开(公告)日：2022-02-08

申请号：US16698019

申请日：2019-11-27

Applicant: TDK Corporation

Inventor： Takeshi Masuda ,  Taeko Tsubokura ,  Taku Murase

IPC: H01F1/057 ,  C22C38/16 ,  C22C38/14 ,  C22C38/00 ,  C22C38/10 ,  C22C38/06

Abstract: An R-T-B permanent magnet comprises rare-earth elements R, transition metal elements T, and boron B; wherein at least some of the rare-earth elements R is Nd and at least one of Tb and Dy; at least some of the transition metal elements T are Fe; the R-T-B permanent magnet comprises a plurality of main phase grains and grain boundary triple points each surrounded by the main phase grains; the grain boundary triple points comprise at least one of Nd and Pr, at least one of Tb and Dy, at least one of Fe and Co, and copper; the average contents of Nd, Pr, Tb, Dy, Fe, Co and Cu each (unit: atom %) are represented by [Nd], [Pr], [Tb], [Dy], [Fe], [Co] and [Cu]; ([Fe]+[Co])/([Nd]+[Pr]) is 2 or more and 5 or less; and [Cu]/([Tb]+[Dy]) is 1 or more and 4 or less.

公开(公告)号：US11242580B2

公开(公告)日：2022-02-08

申请号：US16824218

申请日：2020-03-19

Applicant: TDK CORPORATION

Inventor： Taeko Tsubokura ,  Takeshi Masuda

IPC: C22C28/00 ,  H01F1/057

Abstract: The present invention provides an R-T-B based permanent magnet having excellent magnetic properties and corrosion resistance even when Co content is small.
The R-T-B based permanent magnet in which R is a rare earth element including one or more selected from Nd and Pr and one or more selected from Dy and Tb, T is a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet further includes Zr. A total content of Nd, Pr, Dy, and Tb is 30.00 mass % to 32.20 mass %, Co content is 0.30 mass % to 1.30 mass %, Zr content is 0.21 mass % to 0.85 mass %, and B content is 0.90 mass % to 1.02 mass % with respect to 100 mass % of the R-T-B based permanent magnet.

公开(公告)号：US11817241B2

公开(公告)日：2023-11-14

申请号：US17186770

申请日：2021-02-26

Applicant: TDK Corporation

Inventor： Taeko Tsubokura ,  Toshihiro Kuroshima ,  Koji Mitake ,  Takeshi Masuda

IPC: H01F1/057 ,  H01F41/02

CPC classification number: H01F1/0577 ,  H01F41/0293

Abstract: A magnet structure includes a first sintered magnet, a second sintered magnet, and an intermediate layer disposed between the first sintered magnet and the second sintered magnet. Each of the first sintered magnet and the second sintered magnet independently includes crystal grains containing a rare earth element, a transition metal element, and boron. The intermediate layer contains rare earth element oxide phases and crystal grains containing a rare earth element, transition metal element, and boron. Each of the transition metal elements independently includes Fe or a combination of Fe and Co. An average coverage factor of the rare earth element oxide phases measured on the basis of a cross section perpendicular to the intermediate layer of the magnet structure is within a range of 10% to 69%.

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.