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.