PERMANENT MAGNET AND METHOD FOR PRODUCING PERMANENT MAGNET

摘要

Disclosed is a method for producing a permanent magnet having extremely high coercivity and high magnetic characteristics with high productivity. Specifically, there are performed a first step for adhering at least one of Dy and Tb to at least a part of the surface of an iron-boron-rare earth sintered magnet, and a second step for dispersing at least one of Dy and Tb adhering to the surface of the sintered magnet into the crystal grain boundary phase of the sintered magnet by conducting a heat treatment at a certain temperature. A magnet obtained by mixing a powder of a main phase alloy (which is mainly composed of an R₂T₁₄B phase wherein R represents at least one rare earth element mainly composed of Nd, and T represents a transition metal alloy mainly composed of Fe) and a powder of a liquid phase alloy (which has a higher R content than the R₂T₁₄B phase and is mainly composed of an R-rich phase) at a certain mixing ratio, press molding the thus-obtained mixed powder in a magnetic field, and then sintering the molded body in a vacuum or in an inert gas atmosphere is used as the sintering magnet.