公开(公告)号：US20180287441A1

公开(公告)日：2018-10-04

申请号：US15936790

申请日：2018-03-27

Applicant: TDK CORPORATION

Inventor： Hidetake KITAOKA ,  Makoto IWASAKI ,  Tetsuya HIDAKA ,  Eiji KATO ,  Takuma HAYAKAWA

IPC: H02K1/27 ,  H02K9/19

Abstract: Provided is a motor including a permanent magnet, in which the permanent magnet includes a high temperature side permanent magnet part exposed to a high temperature inside the motor, and a low temperature side permanent magnet part exposed to a temperature lower than the high temperature inside the motor, and a coercive force of the high temperature side permanent magnet part is higher than the coercive force of the low temperature side permanent magnet part.

公开(公告)号：US20200303099A1

公开(公告)日：2020-09-24

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：US20200303098A1

公开(公告)日：2020-09-24

申请号：US16823487

申请日：2020-03-19

Applicant: TDK CORPORATION

Inventor： Mariko FUJIWARA ,  Makoto IWASAKI

IPC: H01F1/057 ,  C22C38/16 ,  C22C38/14 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00 ,  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：US20180277288A1

公开(公告)日：2018-09-27

申请号：US15928378

申请日：2018-03-22

Applicant: TDK CORPORATION

Inventor： Makoto IWASAKI ,  Tetsuya HIDAKA ,  Eiji KATO ,  Takuma HAYAKAWA ,  Hidetake KITAOKA

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

Abstract: Provided is an R-T-B based rare earth magnet. R is one or more rare earth elements, T is one or more transition metal elements essentially including Fe or Fe and Co, and B is boron. B content with respect to a total R-T-B based rare earth magnet is 0.80 mass % or more and 0.98 mass % or less. The R-T-B based rare earth magnet includes an R1T4B4 phase.

公开(公告)号：US20170076846A1

公开(公告)日：2017-03-16

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: H01F7/02 ,  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.

Abstract translation: R-T-B系烧结磁体包括第一主表面和第一侧表面。 第一主表面的矫顽力高于第一侧表面的矫顽力。 ΔHcjM≤60kA/ m，其中ΔHcjM是第一主表面具有最高矫顽力的部分与第一主表面具有最低矫顽力的部分之间的矫顽力差。 ΔHcjG≤60kA/ m，其中ΔHcjG是在第一横截面上具有最高矫顽力的部分与第一横截面具有最低矫顽力的部分之间的矫顽力的差异与第一横截面是横截面平行 到第一主表面并且以预定长度或更长的距离与第一主表面间隔开。

公开(公告)号：US20210296029A1

公开(公告)日：2021-09-23

申请号：US17207950

申请日：2021-03-22

Applicant: TDK CORPORATION

Inventor： Hiroki KAWAMURA ,  Makoto IWASAKI

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

Abstract: 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：US20200312491A1

公开(公告)日：2020-10-01

申请号：US16827851

申请日：2020-03-24

Applicant: TDK CORPORATION

Inventor： Hiroki KAWAMURA ,  Hidetake KITAOKA ,  Makoto IWASAKI

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

Abstract: An alloy for R-T-B based permanent magnet in which R is a rare earth element, T is a combination of Fe and Co, and B is boron. R includes one or more selected from Nd, Pr, Dy, and Tb. The alloy for R-T-B based permanent magnet includes M and C. M is one or more selected from Al, Cu, Zr, and Ga. Relative to 100 mass % of the alloy for R-T-B based permanent magnet, a total content of Nd, Pr, Dy, and Tb is 28.00 mass % or more and 34.00 mass % or less, Co content is 0.05 mass % or more and 3.00 mass % or less, B content is 0.70 mass % or more and 0.95 mass % or less, C content is 0.12 mass % or more and 0.19 mass % or less, a total content of M is more than 0 mass % and 4.00 mass % or less, and Fe is a substantial balance.

公开(公告)号：US20200303097A1

公开(公告)日：2020-09-24

申请号：US16822772

申请日：2020-03-18

Applicant: TDK CORPORATION

Inventor： Makoto IWASAKI ,  Akihiro HARADA

IPC: H01F1/057 ,  C22C30/02

Abstract: An R-T-B based permanent magnet wherein R is one or more rare earth elements, T is Fe and Co, and B is boron. The R-T-B based permanent magnet includes M, C and N, wherein M is two or more selected from Cu, Ga, Mn, Zr, and Al, and includes at least Cu and Ga. A total content of R is ≥29.0 and ≤33.5 mass %, Co content is ≥0.10 and ≤0.49 mass %, B content is ≥0.80 and ≤0.96 mass %, a total content of M is ≥0.63 and ≤4.00 mass %, Cu content is ≥0.51 and ≤0.97 mass %, Ga content is ≥0.12 and ≤1.07 mass %, C content is ≥0.065 and ≤0.200 mass %, N content is ≥0.023 and ≤0.323 mass %, and Fe is a substantial balance.

公开(公告)号：US20190295752A1

公开(公告)日：2019-09-26

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

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 3.48 m(B)−2.67≤m (Zr)≤3.48 m(B)−1.87 in which m (B) (mass %) is B content and m (Zr) (mass %) is Zr content.

公开(公告)号：US20190276917A1

公开(公告)日：2019-09-12

申请号：US16295420

申请日：2019-03-07

Applicant: TDK CORPORATION

Inventor： Makoto IWASAKI

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

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.