R-T-B SINTERED MAGNET AND PRODUCTION METHOD THEREFOR
2022-06-06
1260
3578K
0
The R-T-B sintered magnet according to one embodiment of the present invention has a composition comprising : 27-37 mass% of R (R represents at least one of the rare-earth elements and essentially includes Nd and/or Pr); 0.75-0.97 mass% of B; 0.1-1.0 mass% of Ga; 0-1.0 mass% of Cu; at least 61.03 mass% of T (T represents at least one member selected from the group consisting of Fe, Co, Al, Mn, and Si, and essentially includes Fe such that the Fe content is at least 80 mass% with respect to T overall). The molar ratio of T with respect to B ([T]/[B]) exceeds 14.0. The amount of R in the surface portion of the magnet is greater than that in the central portion of the magnet, while the amount of Ga in the surface portion of the magnet is greater than that in the central portion of the magnet. The molar ratio of T with respect to B ([T]/[B]) in the surface portion of the magnet is higher than that in the central portion of the magnet.