ANISOTROPIC RARE EARTH-IRON-BORON AND RARE EARTH-IRON-COBALT-BORON MAGNET.

摘要

A hot press molding product or a HIP molding product having any of a composition comprising 10 to 20 at.% of R, 3 to 20 at.% of B, 0.001 to 5.0 at.% of one or more atoms selected among Ga, Zr and Hf, and the balance of Fe and unavoidable impurities, a composition comprising 10 to 20 at.% of R, 3 to 20 at.% of B, 0.001 to 5.0 at.% of one or more atoms selected among Ti, V, Nb, Ta, Al and Si, and the balance of Fe and unavoidable impurities, and a composition comprising 0.1 to 50 at.% of Co in addition to any of the two abovementioned compositions. It has an aggregate structure of crystal grains with a mean diameter of 0.05 to 20 mu m wherein a tetragonal R2Fe14B or R2(Fe, Co)14B intermetallic compound constitutes a main phase and crystal grains having a major axis (b) to minor axis (a) ratio of less than 2 account for at least 50 vol% of all the crystal grains.