R-T-B SINTERED MAGNET
2022-06-06
3910
1970K
0
This R-T-B sintered magnet includes a main-phase crystal and a grain-boundary phase, and includes 27.5-35.0 mass% of R (where R is at least one rare-earth element, necessarily including Nd and Pr), 0.80-1.05 mass% of B, 0.05-1.0 mass% of Ga, and 0-2 mass% of M (where M is at least one of Cu, Al, Nb, and Zr), the remainder being T (T is Fe or Fe and Co) and impurities. Pr/Nd, which is the ratio of the concentration of Pr to the concentration of Nd in the center section of the main-phase crystal grains positioned at a depth of 300 μm from the magnet surface, is less than 1; Pr/Nd, which is the ratio of the concentration of Pr to the concentration of Nd within the two-particle grain boundary positioned at a depth of 300 μm from the magnet surface, is greater than 1; and the magnet includes a portion in which the Ga concentration gradually decreases from the magnet surface toward the interior of the magnet.