RARE EARTH PERMANENT MAGNET AND METHOD FOR PREPARING SAME

摘要

Disclosed in the present invention are a rare earth permanent magnet and a method for preparing the same. There is a phenomenon of heavy rare earth elements volume diffusion in the material of the rare earth permanent magnet from the magnet surface to the depth of 5μm to 100μm inside the magnet in the direction of the magnetic field orientation, forming a volume diffusion layer. The volume diffusion region is divided into magnet units having a volume of 10 * 100 * 5 μm, wherein the concentration difference of the heavy rare earth elements in the magnet units at each position within the volume diffusion layer is 0.5 at% or less. Provided is a sintered neodymium-iron-boron magnet having a high intrinsic coercive force Hcj without affecting the remanence Br and the maximum magnetic energy product (BH) max. In the method of preparing the rare earth permanent magnet, the rough magnet coated with heavy rare earth source slurry is subjected to microwave heat treatment under vacuum conditions. The method can effectively improve the heating efficiency, shorten the heat treatment time, reduce the energy consumption and reduce the magnet production cost.