公开(公告)号：US10530198B2

公开(公告)日：2020-01-07

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: 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.

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.

公开(公告)号：US09613737B2

公开(公告)日：2017-04-04

申请号：US14351199

申请日：2012-10-11

Applicant: TDK CORPORATION

Inventor： Eiji Kato ,  Chikara Ishizaka ,  Taeko Tsubokura ,  Tamotsu Ishiyama ,  Nobuhiro Jingu

IPC: C22C33/02 ,  C22C38/10 ,  B22D11/06 ,  H01F1/053 ,  H01F1/057 ,  H01F1/08 ,  H01F41/02 ,  C22C38/00 ,  C22C38/06 ,  C22C38/14 ,  C22C38/16

CPC classification number: H01F1/053 ,  B22D11/0611 ,  C22C33/02 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  C22C2202/02 ,  H01F1/0536 ,  H01F1/0571 ,  H01F1/0577 ,  H01F1/086 ,  H01F41/0266

Abstract: An R-T-B sintered magnet including a composition containing a rare earth element, a transition element and boron, containing essentially no dysprosium as a rare earth element, and having crystal grains with a composition containing a rare earth element, a transition element and boron, and grain boundary regions formed between the crystal grains, wherein the triple point regions which are grain boundary regions surrounded by 3 or more crystal grains have a composition containing a rare earth element, a transition element and boron and have a higher mass ratio of the rare earth element than the crystal grains, the average value of the area of the triple point regions in a cross-section being no greater than 2 μm2 and the standard deviation of the area distribution being no greater than 3.

公开(公告)号：US09514869B2

公开(公告)日：2016-12-06

申请号：US14378432

申请日：2013-02-13

Applicant: TDK CORPORATION

Inventor： Masashi Miwa ,  Haruna Nakajima ,  Ken-ichi Nishikawa ,  Tetsuya Hidaka ,  Jun Hagiwara ,  Chikara Ishizaka

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

CPC classification number: H01F1/057 ,  B22F3/10 ,  C22C38/00 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  H01F1/0577 ,  H01F7/02

Abstract: The present invention provides an R-T-B based sintered magnet including R2T14B crystal grains wherein; a grain boundary is formed by two or more adjacent R2T14B crystal grains, an R—O—C concentrated part, in which concentrations of R, O and C are higher than those in the R2T14B crystal grains respectively, is in the grain boundary, and an area of the R—O—C concentrated part occupying in that of the grain boundary on a cut surface of the R-T-B based sintered magnet is within a range of 10% or more to 75% or less.

Abstract translation: 本发明提供一种包含R2T14B晶粒的R-T-B系烧结磁体，其中： 晶界由两个或更多个相邻的R2T14B晶粒形成，其中R，O和C的浓度分别高于R2T14B晶粒中的R-O-C浓缩部分在晶界中，并且 在RTB型烧结磁体的切断面上占据晶界边界的R-O-C浓缩部分的面积在10％以上至75％以下的范围。

公开(公告)号：US20140286815A1

公开(公告)日：2014-09-25

申请号：US14351119

申请日：2012-10-11

Applicant: TDK CORPORATION

Inventor： Tamotsu Ishiyama ,  Taeko Tsubokura ,  Eiji Kato ,  Nobuhiro Jingu ,  Chikara Ishizaka

IPC: H01F1/053 ,  H01F1/08 ,  H01F41/02

CPC classification number: H01F1/053 ,  B22D11/0611 ,  C22C33/02 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  C22C2202/02 ,  H01F1/0536 ,  H01F1/0571 ,  H01F1/0577 ,  H01F1/086 ,  H01F41/0266

Abstract: An R-T-B based alloy strip containing dendritic crystals including a R2T14B phase, wherein on at least one surface, the average value for the widths of the dendritic crystals is no greater than 60 μm, and the number of crystal nuclei in the dendritic crystals is at least 500 per 1 mm square area.

Abstract translation: 一种含有包含R2T14B相的树枝状晶体的RTB基合金条，其中在至少一个表面上，树枝状晶体的宽度的平均值不大于60μm，树枝状晶体中的晶核数目至少为 每平方毫米面积500个。

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.

公开(公告)号：US09997284B2

公开(公告)日：2018-06-12

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 ,  C22C38/00 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  B22F3/10 ,  H01F7/02

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

公开(公告)号：US09607742B2

公开(公告)日：2017-03-28

申请号：US14351119

申请日：2012-10-11

Applicant: TDK CORPORATION

Inventor： Tamotsu Ishiyama ,  Taeko Tsubokura ,  Eiji Kato ,  Nobuhiro Jingu ,  Chikara Ishizaka

IPC: C22C33/02 ,  C22C38/10 ,  B22D11/06 ,  H01F1/053 ,  H01F1/057 ,  H01F1/08 ,  H01F41/02 ,  C22C38/00 ,  C22C38/06 ,  C22C38/14 ,  C22C38/16

CPC classification number: H01F1/053 ,  B22D11/0611 ,  C22C33/02 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  C22C2202/02 ,  H01F1/0536 ,  H01F1/0571 ,  H01F1/0577 ,  H01F1/086 ,  H01F41/0266

Abstract: An R-T-B based alloy strip containing dendritic crystals including a R2T14B phase, wherein on at least one surface, the average value for the widths of the dendritic crystals is no greater than 60 μm, and the number of crystal nuclei in the dendritic crystals is at least 500 per 1 mm square area.

公开(公告)号：US20150235750A1

公开(公告)日：2015-08-20

申请号：US14378428

申请日：2013-02-13

Applicant: TDK CORPORATION

Inventor： Masashi Miwa ,  Haruna Nakajima ,  Ken-ichi Nishikawa ,  Tetsuya Hidaka ,  Jun Hagiwara ,  Chikara Ishizaka

IPC: H01F7/02

CPC classification number: H01F7/021 ,  B22F1/0007 ,  B22F3/02 ,  B22F3/24 ,  B22F2003/248 ,  B22F2202/05 ,  B22F2999/00 ,  C22C33/0278 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  H01F1/0577

Abstract: The present invention provides an R-T-B based sintered magnet including R2T14B crystal grains wherein; a grain boundary is formed by two or more adjacent R2T14B crystal grains, an R—O—C concentrated part, in which concentrations of R, O and C are higher than those in the R2T14B crystal grains respectively, is in the grain boundary, and a ratio (O/R) of O atom to R atom in the R—O—C concentrated part satisfies the following formula (1): 0.4

Abstract translation: 本发明提供一种包含R2T14B晶粒的R-T-B系烧结磁体，其中： 晶界由两个或更多个相邻的R2T14B晶粒形成，其中R，O和C的浓度分别高于R2T14B晶粒中的R-O-C浓缩部分在晶界中，并且 R-O-C浓缩部分中的O原子与R原子的比率（O / R）满足下式（1）：0.4 <（O / R）<0.7。

公开(公告)号：US20140335268A1

公开(公告)日：2014-11-13

申请号：US14340957

申请日：2014-07-25

Applicant: TDK Corporation

Inventor： Satoshi Tanaka ,  Fumitaka Baba ,  Makoto Iwasaki ,  Chikara Ishizaka

IPC: H01F41/02 ,  H01F41/00

CPC classification number: H01F41/0293 ,  B22F2207/01 ,  B60L50/61 ,  B60L2220/14 ,  B60L2220/16 ,  B60L2220/50 ,  C22C38/002 ,  C22C38/005 ,  H01F1/0577 ,  H01F41/005 ,  H02K1/02 ,  H02K1/04 ,  H02K1/276 ,  Y02T10/6217 ,  Y02T10/641 ,  Y02T10/7077 ,  Y10T428/32

Abstract: A rare earth sintered magnet 10 including a magnet body that includes a rare earth compound, and a protective layer on the magnet body, having a first layer and a second layer in that order from the magnet body side, wherein the surface portion of the magnet body has a higher heavy rare earth element content than the interior of the magnet body that is surrounded by the surface portion, the first layer includes a rare earth oxide, the mass ratio of the heavy rare earth element being 1 or greater with respect to the light rare earth element, and the second layer includes an oxide containing iron and/or boron which is different from the rare earth oxide, the second layer having a lower rare earth oxide content than the first layer.

Abstract translation: 包括稀土类化合物的磁体和磁铁体上的保护层的稀土类烧结磁体10具有从磁铁体侧依次的第一层和第二层，其中磁体的表面部分 本体具有比由表面部包围的磁体的内部更高的重稀土元素含量，第一层包括稀土类氧化物，重稀土类元素的质量比相对于 轻稀土元素，第二层包括与稀土氧化物不同的含有铁和/或硼的氧化物，第二层具有比第一层低的稀土氧化物含量。