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    R-T-B BASED PERMANENT MAGNET
    1.
    发明申请
    R-T-B BASED PERMANENT MAGNET 有权

    公开(公告)号：US20230025223A1

    公开(公告)日：2023-01-26

    申请号：US17779619

    申请日：2020-11-26

    Applicant: TDK CORPORATION

    Inventor： Yoshinori FUJIKAWA ,  Atsushi KODA ,  Mika JINGU ,  Takashi WATANABE

    IPC: H01F1/057 ,  C22C38/00

    Abstract: An R-T-B based permanent magnet including R2T14B main phase crystal grains and a grain boundary. R represents one or more rare earth elements, T represents one or more iron group elements essentially including Fe or Fe and Co, and B represents boron. In a cross-section parallel to the alignment direction of the R-T-B based permanent magnet, the coverage of the R2T14B main phase crystal grains is 50.0% or more, and the area ratio of the R2T14B main phase crystal grains is 92.0% or more.

    RARE EARTH BASED MAGNET
    2.
    发明申请
    RARE EARTH BASED MAGNET 审中-公开
    基于稀土的磁铁

    公开(公告)号：US20140290803A1

    公开(公告)日：2014-10-02

    申请号：US14228808

    申请日：2014-03-28

    Applicant: TDK CORPORATION

    Inventor： Eiji KATO ,  Yoshinori FUJIKAWA ,  Taeko TSUBOKURA ,  Chikara ISHIZAKA ,  Katsuo SATO

    IPC: H01F1/153 ,  H01F1/053

    CPC classification number: H01F1/0577 ,  H01F41/0273

    Abstract: The present invention provides a rare earth based magnet including R2T14B main-phase crystal grains, and two-grain boundary phases between adjacent two R2T14B main-phase crystal grains, the two-grain boundary phases are controlled such that the thickness thereof is 5 nm or more and 500 nm or less, and it is composed of a phase with a magnetism different from that of a ferromagnet.

    Abstract translation: 本发明提供一种包含R2T14B主相晶粒和相邻的两个R2T14B主相晶粒之间的双晶界相的稀土类磁体，控制两晶界相的厚度为5nm， 多于500nm或更小，并且由具有与铁磁体不同的磁性的相组成。

    R-T-B-BASED PERMANENT MAGNET AND METHOD FOR PRODUCING SAME, MOTOR, AND AUTOMOBILE
    3.
    发明申请
    R-T-B-BASED PERMANENT MAGNET AND METHOD FOR PRODUCING SAME, MOTOR, AND AUTOMOBILE 有权

    公开(公告)号：US20230118859A1

    公开(公告)日：2023-04-20

    申请号：US17911760

    申请日：2021-03-29

    Applicant: TDK CORPORATION

    Inventor： Yoshinori FUJIKAWA ,  Reiji YAMADA

    IPC: H01F1/057 ,  C22C30/02 ,  B22F9/02 ,  B22F3/16

    Abstract: An R-T-B-based permanent magnet which contains R that represents at least one rare earth element essentially including Tb or Dy, T that represents Fe or at least one iron-group element essentially including Fe and Co, and B that represents boron, and further contains Cu. The total content of R is 28.35 to 29.95% by mass, inclusive, the content of Cu is 0.05 to 0.40% by mass, inclusive, and the content of B is 0.93 to 1.00% by mass, inclusive. The distribution of the concentration of Tb or Dy decreases from the outside of the R-T-B-based permanent magnet toward the inside of the R-T-B-based permanent magnet.

    R-T-B BASED PERMANENT MAGNET
    4.
    发明申请
    R-T-B BASED PERMANENT MAGNET 审中-公开

    公开(公告)号：US20190304638A1

    公开(公告)日：2019-10-03

    申请号：US16367650

    申请日：2019-03-28

    Applicant: TDK CORPORATION

    Inventor： Yuki NAGAMINE ,  Masashi MIWA ,  Yoshinori FUJIKAWA

    IPC: H01F1/055 ,  C22C38/16 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00

    Abstract: An R-T-B based permanent magnet excellent in magnetic properties relatively reduces the amount of a heavy rare earth element used. An R-T-B based permanent magnet, wherein R represents a rare earth element, T an iron group element and B boron, includes main phase grains including an R2T14B crystal phase and grain boundaries formed between main phase grains. Grain boundaries include R-O-C-N concentrated parts where concentrations of R, O, C and N are all higher than those in main phase grains. C/R(S)>C/R(C) is satisfied in which C/R(S) represents a C/R ratio (atomic ratio) in R-O-C-N concentrated parts present in a surface of a R-T-B based permanent magnet and C/R(C) represents a C/R ratio (atomic ratio) in the R-O-C-N concentrated parts present in the center of a R-T-B based permanent magnet, and a heavy rare earth element RH is included in the R-T-B based permanent magnet.

    R-T-B BASED SINTERED MAGNET
    5.
    发明申请
    R-T-B BASED SINTERED MAGNET 审中-公开

    公开(公告)号：US20180286545A1

    公开(公告)日：2018-10-04

    申请号：US15939778

    申请日：2018-03-29

    Applicant: TDK CORPORATION

    Inventor： Yoshinori FUJIKAWA ,  Masashi MIWA

    IPC: H01F1/057 ,  H01F41/02 ,  C22C38/00

    CPC classification number: H01F1/0577 ,  C22C38/005 ,  H01F41/0293

    Abstract: An R-T-B based sintered magnet including a plural number of main phase particles having an R2T14B type crystal structure. R is at least one rare earth element essentially including heavy rare earth elements RH, T is at least one transition metal element essentially including Fe or Fe and Co, and B is boron. At least one of the main phase particles is a reverse core-shell main phase particle including a core part and a shell part, in which CRC/CRS>1.0 is satisfied when a total RH concentration (at %) in the core part is defined as CRC and a total RH concentration (at %) in the shell part is defined as CRS. An existence ratio of the reverse core-shell main phase particles is larger in a surface layer part of the magnet than in a central part of the magnet.

    R-T-B BASED PERMANENT MAGNET
    8.
    发明申请
    R-T-B BASED PERMANENT MAGNET 有权

    公开(公告)号：US20220199301A1

    公开(公告)日：2022-06-23

    申请号：US17554208

    申请日：2021-12-17

    Applicant: TDK Corporation

    Inventor： Kenichi SUZUKI ,  Yoshinori FUJIKAWA

    IPC: H01F1/057 ,  C22C38/00

    Abstract: To provide an R-T-B based permanent magnet in which the residual magnet flux density and the coercivity are improved. Provided is an R-T-B based permanent magnet including a rare-earth element R, and transition metal elements T and B. The R-T-B based permanent magnet includes at least Nd as R, the R-T-B based permanent magnet includes at least Fe among Fe and Co as T, the R-T-B based permanent magnet includes a plurality of main phase grains containing a crystal of R2T14B, and a two-grain boundary located between two main phase grains adjacent in an axis-of-easy-magnetization direction, the thickness of the two-grain boundary is 3 nm or less, and the two-grain boundary is crystalline, and is non-oriented.

    R-T-B BASED SINTERED MAGNET
    9.
    发明申请
    R-T-B BASED SINTERED MAGNET 审中-公开

    公开(公告)号：US20180301256A1

    公开(公告)日：2018-10-18

    申请号：US15939719

    申请日：2018-03-29

    Applicant: TDK CORPORATION

    Inventor： Yoshinori FUJIKAWA ,  Masashi MIWA

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

    CPC classification number: H01F1/0577 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  C22C2202/02 ,  H01F41/0266 ,  H01F41/0293

    Abstract: An R-T-B based sintered magnet including main phase particles having an R2T14B type crystal structure. R is at least one rare earth element essentially including a heavy rare-earth element RH. T is at least one transition metal element essentially including Fe or Fe and Co. B is boron. At least one of the main phase particles includes low RH crystal phases inside the main phase particle. The low RH crystal phases include the R2T14B type crystal structure, wherein an RH concentration in the low RH crystal phases is relatively lower than the RH concentration in the whole main phase particles. The R-T-B based sintered magnet may satisfy rs−rc≥20% when an existence ratio of the main phase particles including the low RH crystal phases in a magnet surface layer part is rs (%) and the same in a magnet central part is rc (%).

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