公开(公告)号：US12020836B2

公开(公告)日：2024-06-25

申请号：US17356178

申请日：2021-06-23

申请人： TDK CORPORATION

发明人： Koji Miura ,  Masashi Miwa

IPC分类号： H01F1/057 ,  C22C38/00

CPC分类号： H01F1/0577 ,  C22C38/005

摘要： To provide an R-T-B based permanent magnet having a high residual magnetic flux density Br at room temperature and a high coercivity HcJ at high temperature. In the R-T-B based permanent magnet, R is a rare earth element, T is an iron group element, and B is boron, and the R-T-B based permanent magnet includes a light rare earth element and a heavy rare earth element as R. The R-T-B based permanent magnet further includes Al, Ga, and Zr. With respect to 100 mass % of the R-T-B based permanent magnet, a total content of R is 28.50 mass % to 30.25 mass % (not including 28.50 mass %), B content is 0.93 mass % to 0.98 mass %, Al content is 0.03 mass % to 0.19 mass %, Ga content is 0.03 mass % to 0.15 mass %, and Zr content is 0.30 mass % to 0.50 mass %.

公开(公告)号：US11410804B2

公开(公告)日：2022-08-09

申请号：US16819071

申请日：2020-03-14

申请人： TDK Corporation

发明人： Masashi Miwa

IPC分类号： H01F1/057 ,  H01F41/02 ,  H01F7/02 ,  C22C38/00

摘要： A permanent magnet 2 includes Nd, Fe, and B, the permanent magnet 2 contains a plurality of main phase grains; and grain boundaries positioned between the main phase grains, the main phase grains include Nd, Fe, and B, at least a portion of the grain boundaries contains an R′—O—C phase, the R′—O—C phase includes a rare earth element R′, O, and C, the concentration of each of R′, O, and C in the R′—O—C phase is higher compared to the main phase grains, the permanent magnet 2 comprises a surface layer portion 21 and a central portion 22, the surface layer portion 21 is positioned on the surface side of the permanent magnet 2, the central portion 22 is positioned on the inner side of the permanent magnet 2, the proportion of the area of the R′—O—C phase occupying in a cross-section of the surface layer portion 21 is S1 %, the proportion of the area of the R′—O—C phase occupying in a cross-section of the central portion 22 is S2%, and S1 is higher than S2.

公开(公告)号：US10734143B2

公开(公告)日：2020-08-04

申请号：US15940049

申请日：2018-03-29

申请人： TDK CORPORATION

发明人： Yoshinori Fujikawa ,  Masashi Miwa

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

摘要： An R-T-B based sintered magnet including a main phase particle comprising an R2T14B type crystal structure. R is at least one rare earth element, T is at least one transition metal element essentially including Fe or Fe and Co, and B is boron. The R-T-B based sintered magnet includes a magnet surface layer part and a magnet central part existing inside the magnet surface layer part. A crystal orientation degree of the main phase particle in the magnet surface layer part having a magnetic pole surface is lower than the crystal orientation degree of the main phase particle in the magnet central part.

公开(公告)号：US09773599B2

公开(公告)日：2017-09-26

申请号：US14378428

申请日：2013-02-13

申请人： TDK CORPORATION

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

IPC分类号： H01F7/02 ,  H01F1/057

CPC分类号： 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

摘要： 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

公开(公告)号：US11657934B2

公开(公告)日：2023-05-23

申请号：US16367917

申请日：2019-03-28

申请人： TDK CORPORATION

发明人： Yuki Nagamine ,  Masashi Miwa ,  Yoshinori Fujikawa

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

CPC分类号： H01F1/0577 ,  C22C38/002 ,  C22C38/005 ,  C22C38/06 ,  C22C38/10 ,  C22C38/16 ,  C22C2202/02 ,  H01F41/0293

摘要： An R-T-B based permanent magnet, excellent in magnetic properties relatively reducing amount of heavy rare earth element used, wherein R represents rare earth element, T iron group element and B boron, includes main phase grains including R2T14B crystal phase and grain boundaries 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 in main phase grains. O/R(S)>O/R(C) wherein O/R(S) represents O/R ratio (atomic ratio) in R—O—C—N concentrated parts in a surface of an R-T-B based permanent magnet and O/R(C) represents O/R ratio (atomic ratio) in R—O—C—N concentrated parts in a center of an R-T-B based permanent magnet. A heavy rare earth element RH is in a surface of an R-T-B based permanent magnet as R. R—O—C—N concentrated parts in a surface of an R-T-B based permanent magnet have RH/R ratio (atomic ratio) of 0.2 or less.

公开(公告)号：US10943717B2

公开(公告)日：2021-03-09

申请号：US15440755

申请日：2017-02-23

申请人： TDK CORPORATION

发明人： Masashi Miwa ,  Takurou Iwasa

IPC分类号： H01F1/057 ,  B22F9/04 ,  B22F3/16 ,  C22C33/02 ,  B22D11/00 ,  B22F5/00 ,  C21D3/06 ,  C22C38/00 ,  C22C38/06 ,  C22C38/10 ,  C22C38/14 ,  C22C38/16 ,  H01F1/058

摘要： An R-T-B based permanent magnet includes main phase grains composed of R2T14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 μm or more and 2.8 μm or less. The R-T-B based permanent magnet contains at least C and Zr in addition to R, T, and B. B is contained at 0.75 mass % or more and 0.88 mass % or less. Zr is contained at 0.65 mass % or more and 5.00 mass % or less. A formula (1) of 5.0≤[B]+[C]−[Zr]≤5.6 is satisfied, where [B] is a B content represented by atom %, [C] is a C content represented by atom %, and [Zr] is a Zr content represented by atom %.

公开(公告)号：US10748685B2

公开(公告)日：2020-08-18

申请号：US15939719

申请日：2018-03-29

申请人： TDK CORPORATION

发明人： Yoshinori Fujikawa ,  Masashi Miwa

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

摘要： 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 (%).

公开(公告)号：US10109403B2

公开(公告)日：2018-10-23

申请号：US14909563

申请日：2014-08-08

申请人： TDK CORPORATION

发明人： Isao Kanada ,  Hiroyuki Ono ,  Eiji Kato ,  Masashi Miwa

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

摘要： 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：US09514869B2

公开(公告)日：2016-12-06

申请号：US14378432

申请日：2013-02-13

申请人： TDK CORPORATION

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

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

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

摘要： 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.

摘要翻译： 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：US11145444B2

公开(公告)日：2021-10-12

申请号：US16364443

申请日：2019-03-26

申请人： TDK Corporation

发明人： Mariko Fujiwara ,  Masashi Miwa

IPC分类号： H01F1/057 ,  C22C30/02 ,  B22F9/04 ,  B22F3/16 ,  B22F3/24 ,  C22C38/00

摘要： An R-T-B-based sintered magnet 2 contains a rare earth element R, a transition metal element T, B, Ga, and O, the sintered magnet 2 includes a magnet body 4 and an oxidized layer 6 covering the magnet body 4, the magnet body 4 includes main phase grains 8 containing a crystal of R2T14B and a grain boundary phase 1 positioned between the main phase grains 8 and containing R, the oxidized layer 6 includes a plurality of oxide phases 3A containing R, T, Ga, and O, the oxide phase 3A satisfies the following Formulas (1) and (2) regarding the content (unit: atom %) of each element, and the oxide phase 3A in the oxidized layer 6 covers the grain boundary phase 1 in the magnet body 4. 0.3≤[R]/[T]≤0.5  (1) 0.2≤[O]/([R]+[T]+[Ga]+[O])≤0.7  (2)