公开(公告)号：US20180040400A1

公开(公告)日：2018-02-08

申请号：US15649048

申请日：2017-07-13

Applicant: TDK CORPORATION

Inventor： Keiji TAKEDA ,  Shota MIYAZAKI

IPC: H01F1/057 ,  C22C38/00

Abstract: An R-T-B based rare earth permanent magnet is expressed by a compositional formula: (R11-x(Y1-y-z Cey Laz)x)aTbBcMd in which R1 is one or more kinds of rare earth element not including Y, Ce and La, “T” is one or more kinds of transition metal, and includes Fe or Fe and Co as an essential component, “M” is an element having Ga or Ga and one or more kinds selected from Sn, Bi and Si, and 0.4≦x≦0.7, 0.00≦y+z≦0.20, 0.16≦a/b≦0.28, 0.050≦c/b≦0.075 and 0.005≦d/b≦0.028. The magnet includes a main phase, including a compound having a R2T14B type tetragonal structure, and a grain boundary phase. D10, D50, D90 of crystal grain diameter according to the main phase crystal grains satisfies the following formula: D50≦4.00 μm and (D90−D10)/D50≦1.60. A coating rate of the grain boundary is 70.0% or more.

公开(公告)号：US20170047151A1

公开(公告)日：2017-02-16

申请号：US15304193

申请日：2015-03-10

Applicant: TDK CORPORATION

Inventor： Shogo KADOTA ,  Kenichi SUZUKI ,  Yuji UMEDA ,  Ryuji HASHIMOTO ,  Keiji TAKEDA

IPC: H01F1/057 ,  C22C38/00 ,  H01F1/055 ,  B22F3/16 ,  H01F1/058 ,  H01F1/059

CPC classification number: H01F1/057 ,  B22F3/16 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C2202/02 ,  H01F1/0556 ,  H01F1/0557 ,  H01F1/0577 ,  H01F1/058 ,  H01F1/059

Abstract: To provide a permanent magnet which uses Ce of an abundant resource and has a great magnetic anisotropy in rare earth permanent magnets. To obtain a permanent magnet having a high magnetic anisotropy due to the trivalent Ce state by setting the abundance ratio C3/(C3+C4) in the main phase grains to be 0.1≦C3/(C3+C4)≦0.5 where C3 denotes the number of trivalent Ce atoms and C4 denotes the number of tetravalent Ce atoms.

Abstract translation: 提供一种使用丰富资源的Ce并且在稀土永磁体中具有很大的磁各向异性的永磁体。 为了通过将主相晶粒中的丰度比C3 /（C3 + C4）设定为0.1≤C3/（C3 + C4）≤0.5，由于三价Ce状态而获得具有高磁各向异性的永磁体，其中C3表示 三价Ce原子数，C4表示四价Ce原子数。

公开(公告)号：US20210242727A1

公开(公告)日：2021-08-05

申请号：US17059390

申请日：2019-05-17

Applicant: TDK CORPORATION

Inventor： Tomohiro KAJITA ,  Shota MIYAZAKI ,  Keiji TAKEDA

IPC: H02K1/02 ,  H01F1/057 ,  H01F7/02

Abstract: The R-T-B-based magnet contains one or more kinds of rare earth elements (R), a transition metal element (T) including iron or iron and Co as an essential element, B, an element M that is Ga or Ga and Al, and C. When ratios of the number of atoms of R, T, B, M, and C are set as a, b, c, d, and e, respectively, relationships of 14%≤a≤20%, 70%≤b≤82%, 4%≤c≤7%, 0.009≤d/b≤0.035, and 0.025≤e/b≤0.055 are satisfied. The R-T-B-based magnet includes main phase crystal grains having an R2T14B-type tetragonal structure, and a grain boundary phase including an R-T-M-C phase. When ratios of R, T, M, and C in the main phase crystal grains are set as RMP, TMP, MMP, and CMP, and ratios of R, T, M, and C in the R-T-M-C phase are set as RRC, TRC, MRC, and CRC, relationships of RRC>RMP, TRC MMP, and CRC>CMP are satisfied, and a relationship of 0.07≤MRC/TRC≤0.65 is satisfied.

公开(公告)号：US20180294080A1

公开(公告)日：2018-10-11

申请号：US15939878

申请日：2018-03-29

Applicant: TDK CORPORATION

Inventor： Shota MIYAZAKI ,  Keiji TAKEDA

IPC: H01F1/057 ,  C22C38/00 ,  C22C38/10 ,  H01F7/02

Abstract: An object of the present invention is to provide an R-T-B based permanent magnet having a low coercive force and a low magnetizing field, and having a high residual magnetic flux density and a high minor curve flatness even in the low magnetizing field. Provided is an R-T-B based permanent magnet including a main phase crystal grain including a compound having an R2T14B type tetragonal structure and a grain boundary phase existing between the main phase crystal grains, in which R is at least one rare earth element including scandium and yttrium, T is at least one transition metal element including iron, or at least two transition metal elements including iron and cobalt, an average diameter D50 of the main phase crystal grain is 1.00 μm or less, and a content of carbon included in the R-T-B based permanent magnet is 3,000 ppm or more.

公开(公告)号：US20180294079A1

公开(公告)日：2018-10-11

申请号：US15939536

申请日：2018-03-29

Applicant: TDK CORPORATION

Inventor： Keiji TAKEDA ,  Shota MIYAZAKI

IPC: H01F1/057 ,  C22C38/00 ,  C22C38/10 ,  H01F7/02

Abstract: An object of the present invention is to provide an R-T-B based permanent magnet having a low coercive force and a low magnetizing field, and having a high residual magnetic flux density and a high minor curve flatness even in the low magnetizing field. Provided is an R-T-B based permanent magnet including a main phase including a compound having an R2T14B type tetragonal structure and a grain boundary phase existing between the main phases, in which R is at least one rare earth element including scandium and yttrium, T is at least one transition metal element including iron, or at least two transition metal elements including iron and cobalt, the grain boundary includes an R-T-B—C based compound having a higher R concentration, B concentration and C concentration than that of the main phase and having a lower T concentration than that of the main phase.

公开(公告)号：US20210043343A1

公开(公告)日：2021-02-11

申请号：US16965956

申请日：2019-01-29

Applicant: TDK CORPORATION

Inventor： Keiji TAKEDA ,  Shota MIYAZAKI

IPC: H01F1/057 ,  C22C38/00

Abstract: An R-T-B-based rare earth permanent magnet in which the composition formula is represented by (R11-x-ySmXR2y)aTbBcMd, wherein: R1 is one or more rare earth elements not including Sm and Y; R2 is one or more rare earth elements from among Y, Ce, and La; T is Fe, etc.; M is Ga, etc.; x and y are in the region indicated in FIG. 1; the relationships 0.16≤a/b≤0.28, 0.050≤c/b≤0.075, and 0.005≤d/b≤0.028 are satisfied; the R-T-B-based rare earth permanent magnet includes a grain boundary phase and a main phase comprising an R2T14B compound; the average crystal grain diameter of the main-phase crystal grains is D50≤4.00 μm; the granularity distribution is (D90−D10)/D50≤1.60; and the coverage of the grain boundary phase is at least 70.0%.

公开(公告)号：US20180040399A1

公开(公告)日：2018-02-08

申请号：US15648759

申请日：2017-07-13

Applicant: TDK CORPORATION

Inventor： Shota MIYAZAKI ,  Keiji TAKEDA

IPC: H01F1/057 ,  C22C38/00

Abstract: An R-T-B based rare earth permanent magnet is expressed by formula: (R11-x(Y1-y-z Cey Laz)x)aTbBcMd in which, R1 is one or more kinds of rare earth element not including Y, Ce and La. “T” is one or more kinds of transition metal, and includes Fe or Fe and Co as an essential component, “M” is an element having Ga or Ga and one or more of Sn, Bi and Si, 0.4≦x≦0.7, 0.00≦y+z≦0.20, 0.16≦a/b≦0.28, 0.050≦c/b≦0.070, 0.005≦d/b≦0.028, 0.25≦(a-2c)/(b-14c)≦2.00 and 0.025≦d/(b-14c)≦0.500. The magnet has a structure having a main phase, having a compound having a R2T14B type tetragonal structure, and a grain boundary phase, on an arbitrary cross sectional area, an area ratio of R-T-M, T-rich and R-rich phases, with respect to a total grain boundary phase area is 10.0% or more, 60.0% or less and 70.0% or less, respectively, and the coating rate of the grain boundary phase is 70.0% or more.