Anisotropic rare earth-based permanent magnet material

摘要

Disclosed is a magnetically anisotropic rare earth-based permanent magnet having a nanocomposite structure consisting of fine dispersion of a magnetically hard phase, e.g., Nd₂Fe₁₄B, in alignment relative to the easy magnetization axis, a magnetically soft phase and a non-magnetic phase having a melting point lower than those of the magnetically hard and soft phases. The permanent magnet is prepared in a process in which a quenched thin magnet alloy ribbon having a composition capable of forming a magnetically hard phase, magnetically soft phase and non-magnetic phase by a heat treatment is subjected to a heat treatment in a magnetic field of at least 3 T at a temperature not lower than the melting point of the non-magnetic phase so that the liquid phase formed from the non-magnetic phase serves to facilitate rotating orientation of the magnetically hard grains to be aligned in the direction of the magnetic field relative to the easy magnetization axis.