R-T-B RARE EARTH PERMANENT MAGNET

摘要

Sintered material comprising 25 to 35 wt.% of R (R represents at least one rare earth element, provided that the rare earth element comprehends Y), 0.5 to 4.5 wt.% of B, 0.02 to 0.6 wt.% of one or both of Al and Cu, 0.03 to 0.25 wt.% of Zr, 4 wt.% or less (not including 0) of Co and the rest composed substantially of Fe. This sintered material exhibits a coefficient of variation (CV value), being an index for the degree of dispersion of Zr, of 130 or below. This sintered material has an intergranular phase including a region enriched with both Zr and at least one element selected from the group consisting of Cu, Co and R. This sintered material enables inhibiting the growth of grain while minimizing the deterioration of magnetic properties and enables attaining improvement with respect to the width of sintering temperature.