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    Rare earth based magnet
    11.
    发明授权
    Rare earth based magnet 有权

    公开(公告)号：US10083783B2

    公开(公告)日：2018-09-25

    申请号：US14579315

    申请日：2014-12-22

    Applicant: TDK CORPORATION

    Inventor： Yoshinori Fujikawa ,  Yuki Nagamine ,  Wakako Okawa ,  Chikara Ishizaka ,  Eiji Kato ,  Katsuo Sato

    IPC: H01F1/057

    CPC classification number: H01F1/057 ,  H01F1/0577

    Abstract: The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises R2T14B crystal grains as the main phases and the crystal boundary phases among R2T14B crystal grains. The microstructure of the sintered body is controlled by at least containing the first crystal boundary phases and the second crystal boundary phases, wherein the first crystal boundary phases contain at least R-T-M in the ranges of 20 to 40 atomic % for R, 60 to 75 atomic % for T and 1 to 10 atomic % for M, and the second crystal boundary phases contains at least R-T-M in the ranges of 50 to 70 atomic % for R, 10 to 30 atomic % for T and 1 to 20 atomic % for M.

    Rare earth based magnet
    14.
    发明授权
    Rare earth based magnet 有权

    公开(公告)号：US10546672B2

    公开(公告)日：2020-01-28

    申请号：US14229253

    申请日：2014-03-28

    Applicant: TDK CORPORATION

    Inventor： Eiji Kato ,  Yoshinori Fujikawa ,  Taeko Tsubokura ,  Chikara Ishizaka ,  Katsuo Sato

    IPC: H01F1/057

    Abstract: The present invention provides a rare earth based magnet that inhibits the high temperature demagnetization rate even when less or no heavy rare earth elements such as Dy, Tb and the like are used. The rare earth based magnet according to the present invention includes R2T14B main phase crystal grains and grain boundary phases between adjacent main phase crystal grains. In any cross-section of the rare earth based magnet, when evaluating the circular degree of the main phase crystal grains with Wadell's Roundness A, the shape of the main phase crystal grains is controlled such that the Roundness A becomes 0.24 or more.

    Rare earth based magnet
    17.
    发明授权
    Rare earth based magnet 有权

    公开(公告)号：US10090087B2

    公开(公告)日：2018-10-02

    申请号：US14578713

    申请日：2014-12-22

    Applicant: TDK CORPORATION

    Inventor： Yoshinori Fujikawa ,  Yuki Nagamine ,  Wakako Okawa ,  Chikara Ishizaka ,  Eiji Kato ,  Katsuo Sato

    IPC: H01F1/057 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/16 ,  C22C33/02

    Abstract: The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises R2T14B crystal grains as the major phases and the crystal boundary phases among the R2T14B crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 60 to 80% for R, 15 to 35% for T and 1 to 20% for M.

    Rare earth based magnet
    18.
    发明授权
    Rare earth based magnet 有权
    稀土类磁铁

    公开(公告)号：US09548149B2

    公开(公告)日：2017-01-17

    申请号：US14229296

    申请日：2014-03-28

    Applicant: TDK CORPORATION

    Inventor： Eiji Kato ,  Yoshinori Fujikawa ,  Taeko Tsubokura ,  Chikara Ishizaka ,  Katsuo Sato

    IPC: H01F1/057

    CPC classification number: H01F1/0571 ,  H01F1/0577

    Abstract: The present invention provides a rare earth based magnet having a microstructure in which in a section of the R2T14B main-phase crystal grains, the number density of the fine products in the interior of (inside) the crystal grains is larger than that in the periphery of (outside) the crystal grains. That is, the rare earth based magnet includes R2T14B main-phase crystal grains and grain boundary phases formed between the R2T14B main-phase crystal grains. The R2T14B main-phase crystal grains include a substance where fine products are formed in the crystal grains. In the section of the main-phase crystal grains, when the crystal grains are divided into the interior of the crystal grains and the periphery of the crystal grains with a specific ellipse, the fine products are formed such that the number density in the interior is larger than that in the periphery.

    Abstract translation: 本发明提供一种稀土类磁体，其具有微结构，其中在R2T14B主相晶粒的截面中，晶粒内部（内部）的细微产物的数量密度大于周边 （外）晶粒。 也就是说，稀土类磁体包括在R2T14B主相晶粒之间形成的R2T14B主相晶粒和晶界相。 R2T14B主相晶粒包括在晶粒中形成细小产物的物质。 在主相晶粒的截面中，当晶粒分为晶粒内部和具有特定椭圆的晶粒周边时，形成精细产物，使得内部的数量密度为 大于周边的。

    SINTERED MAGNET
    19.
    发明申请
    SINTERED MAGNET 有权
    烧结磁铁

    公开(公告)号：US20150170810A1

    公开(公告)日：2015-06-18

    申请号：US14409186

    申请日：2013-06-21

    Applicant: TDK Corporation

    Inventor： Masashi Miwa ,  Atsushi Fujiwara ,  Eiji Kato ,  Taeko Tsubokura ,  Koji Mitake ,  Chikara Ishizaka

    IPC: H01F1/057 ,  C22C38/16 ,  B22F3/10 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00 ,  H01F7/02 ,  C22C38/14

    CPC classification number: H01F1/0577 ,  B22F3/10 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  H01F7/02

    Abstract: A sintered magnet of a preferred embodiment has a composition comprising: R (R is a rare earth element that must contain any one of Nd and Pr.): 29.5 to 33.0 mass %; B: 0.7 to 0.95 mass %; Al: 0.03 to 0.6 mass %; Cu: 0.01 to 1.5 mass %; Co: 3.0 mass % or less (provided that 0 mass % is not included.); Ga: 0.1 to 1.0 mass %; C: 0.05 to 0.3 mass %; O: 0.03 to 0.4 mass %; and Fe and other elements: a balance, and wherein a content of heavy rare earth elements in total is 1.0 mass % or less, and wherein the following relations are satisfied: 0.29

    Abstract translation: 优选实施方案的烧结磁体具有如下组成：R（R是必须含有Nd和Pr中的任一种的稀土元素）：29.5〜33.0质量％ B：0.7〜0.95质量％ Al：0.03〜0.6质量％ Cu：0.01〜1.5质量％ Co：3.0质量％以下（不含0质量％）。 Ga：0.1〜1.0质量％ C：0.05〜0.3质量％ O：0.03〜0.4质量％ Fe等元素：余量，其中重稀土元素的含量总计为1.0质量％以下，其中满足以下关系：0.29 <[B] /（[Nd] + [Pr]） <0.40和0.07 <（[Ga] + [C]）/ [B] <0.60，其中[Nd]，[Pr]，[B]，[C]和[Ga]表示Nd，Pr ，B，C和Ga。

    Rare earth based magnet
    20.
    发明授权
    Rare earth based magnet 有权

    公开(公告)号：US10256016B2

    公开(公告)日：2019-04-09

    申请号：US14578621

    申请日：2014-12-22

    Applicant: TDK CORPORATION

    Inventor： Yoshinori Fujikawa ,  Yuki Nagamine ,  Wakako Okawa ,  Chikara Ishizaka ,  Eiji Kato ,  Katsuo Sato

    IPC: H01F1/057

    Abstract: The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises R2T14B crystal grains as the main phases and the crystal boundary phases among the R2T14B crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 25 to 35% for R, 60 to 70% for T and 2 to 10% for M.

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