公开(公告)号：US11205532B2

公开(公告)日：2021-12-21

申请号：US16465397

申请日：2017-11-30

Applicant: TDK CORPORATION

Inventor： Masashi Ito ,  Yuki Nagamine

IPC: H01F1/058 ,  H01F1/055 ,  B22F1/00 ,  C22C33/02 ,  C22C38/00 ,  B22F9/04

Abstract: A permanent magnet includes R and T (R essentially includes Sm one or more of rare earth elements in addition to Sm, and T essentially includes Fe, or Fe and Co, one or more of transition metal elements in addition to Fe, or Fe and Co). A composition ratio of R in the permanent magnet is 20 at % or more and 40 at % or less. A remaining part is substantially only T, or only T and C. T amount is more than 1.5 times of R amount and less than 4.0 times of the R amount. Main phase grains included in the permanent magnet have an Nd5Fe17 type crystal structure. An average crystal grain size of the main phase grains of the permanent magnet is greater than 1 μm. A number ratio of main phase grains having a crystal grain size of less than 0.4 μm is less than 20%.

公开(公告)号：US10886044B2

公开(公告)日：2021-01-05

申请号：US16292681

申请日：2019-03-05

Applicant: TDK CORPORATION

Inventor： Masashi Ito ,  Eiichiro Fukuchi

IPC: H01F1/058 ,  H01F1/053 ,  H01F1/055 ,  C22C38/00

Abstract: A rare earth permanent magnet that is high in residual magnetization and coercivity is obtained and includes R and T. A main phase of crystal grains having an Nd5Fe17 type crystal structure is included. In an X-ray diffraction profile drawn by performing an XRD measurement for a rare earth permanent magnet, peaks of detected intensity are present in specific ranges. In which the detected intensity of the peak with the highest detected intensity in the range of 41.60°

公开(公告)号：US11302465B2

公开(公告)日：2022-04-12

申请号：US16465412

申请日：2017-11-30

Applicant: TDK CORPORATION

Inventor： Ryuji Hashimoto ,  Masashi Ito ,  Eiichiro Fukuchi ,  Yuki Nagamine

IPC: H01F1/057 ,  C22C38/10

Abstract: To provide a rare earth permanent magnet having as a main phase a compound with a Nd5Fe17 crystalline structure having strong coercive force. A rare earth permanent magnet having as a main phase a compound with a Nd5Fe17 crystalline structure, wherein when the composition ratio of the rare earth permanent magnet is expressed as RaT(100-a-b)Cb, where R is one or more rare earth elements requiring Sm, and T is one or more transition metal elements requiring Fe or Fe and Co, a and b satisfy 18

公开(公告)号：US10366814B2

公开(公告)日：2019-07-30

申请号：US15074491

申请日：2016-03-18

Applicant: TDK CORPORATION

Inventor： Masashi Ito ,  Tomoko Kitamura ,  Masaki Tomita

IPC: H01F1/057 ,  H01F1/058

Abstract: The present invention provides a permanent magnet with a composition ratio of RXT(100-X-Y)CY having a main phase with Nd5Fe17 type crystal structure, wherein: R is one or more rare earth elements including Sm as a necessary element, and the rare earth elements are Sm, Y, La, Pr, Ce, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; and T is one or more transition metal elements including Fe or a combination of Fe and Co as necessary elements; and 15

公开(公告)号：US20250111968A1

公开(公告)日：2025-04-03

申请号：US18899295

申请日：2024-09-27

Applicant: TDK Corporation

Inventor： Kazuhiro YOSHIDOME ,  Hiroyuki Matsumoto ,  Shota Otsuka ,  Masashi Ito ,  Hitoshi Ohkubo

IPC: H01F3/08 ,  H01F1/20 ,  H01F41/02

Abstract: A soft magnetic metal powder includes soft magnetic metal particles with a particle size of 5.0 μm or more. (y95/y50−y90/y50)/(0.95−0.90) is 20.0 or less, where y95 (μm) denotes D95, y90 (μm) denotes D90, and y50 (μm) denotes D50 of a particle size distribution of the soft magnetic metal particles with a particle size of 5.0 μm or more. A magnetic core includes soft magnetic metal particles with a Heywood diameter of 5.0 μm or more in a section of the magnetic core. (Y95/Y50−Y90/Y50)/(0.95−0.90) is 20.0 or less, where Y95 (μm) denotes D95, Y90 (μm) denotes D90, and Y50 (μm) denotes D50 of a particle size distribution of the soft magnetic metal particles with a Heywood diameter of 5.0 μm or more.

公开(公告)号：US11081265B2

公开(公告)日：2021-08-03

申请号：US16465402

申请日：2017-11-30

Applicant: TDK CORPORATION

Inventor： Takurou Iwasa ,  Ryuji Hashimoto ,  Masashi Ito

IPC: H01F1/055 ,  C22C33/02 ,  C22C38/00 ,  C22C38/10 ,  H01F1/053

Abstract: A rare-earth sintered magnet contains main phase crystal grains having an Nd5Fe17-type crystal structure, includes R and T (where R represents one or more rare-earth elements that essentially include Sm and T represents Fe or one or more transition metal elements that essentially include Fe and Co), and wherein the compositional ratio of R is 20-40 at % and the remaining portion is substantially T; the remaining portion other than R is substantially only T or only T and C; and when the main phase crystal grains' average grain size in one cross-sectional surface of the rare-earth sintered magnet is defined as Dv, while grain size of individual main phase crystal grains is defined as Di, Dv is at least 1.0 μm, and the main phase crystal grains' area ratio that satisfy 0.7Dv≤Di≤2.0Dv is at least 80% with respect to the area of a cross-sectional surface of the rare-earth sintered magnet.