公开(公告)号：US20190080827A1

公开(公告)日：2019-03-14

申请号：US16123534

申请日：2018-09-06

Applicant: TDK CORPORATION

Inventor： Tetsuya Hidaka ,  Hidetake Kitaoka ,  Eiji Kato

IPC: H01F1/057 ,  H01F7/02

Abstract: Provided is an R-T-B based permanent magnet including main phase grains including an R2T14B compound and a grain boundary. R is one or more rare earth elements essentially including Nd, T is Fe or Fe and Co and B is boron. the R-T-B based permanent magnet further includes X, Z and M. X is one or more selected from Ti, V, Zr, Nb, Hf and Ta, Z is one or more selected from C and N, M essentially includes Ga and further includes one or more selected from Al, Si, Ge, Cu, Bi and Sn. The grain boundary includes an XZ phase having a face-centered cubic structure.

公开(公告)号：US10109403B2

公开(公告)日：2018-10-23

申请号：US14909563

申请日：2014-08-08

Applicant: TDK CORPORATION

Inventor： Isao Kanada ,  Hiroyuki Ono ,  Eiji Kato ,  Masashi Miwa

IPC: H01F1/057 ,  H01F1/055 ,  C22C38/00 ,  C22C38/06 ,  C22C38/10 ,  C22C38/16 ,  H02K1/02 ,  H01F41/02

Abstract: The present invention provides an R-T-B based sintered magnet that inhibits the demagnetization rate at high temperature even when less or no heavy rare earth elements such as Dy, Tb and the like are used. The R-T-B based sintered magnet comprises R2T14B crystal grains and two-grain boundary parts between the R2T14B crystal grains. Two-grain boundary parts formed by a phase containing R, Cu, Co, Ga and Fe with a ratio of 40≤R≤70, 1≤Co≤10, 5≤Cu≤50, 1≤Ga≤15, and 1≤Fe≤40 (wherein, R+Cu+Co+Ga+Fe=100, and R is at least one selected from rare earth elements) exists in the magnet.

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：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。