NEODYMIUM MAGNET AND METHOD FOR MANUFACTURING NEODYMIUM MAGNET BY THREE-DIMENSIONAL GRAIN BOUNDARY DIFFUSION

The present invention provides a neodymium magnet. The neodymium magnet is a neodymium magnet having experienced diffusion and permeation of a heavy rare-earth element; the neodymium magnet comprises surface heavy rare-earth diffusion regions and a core non-diffusion region; the neodymium magnet has surface heavy rare-earth diffusion regions in three-dimensional directions of the magnet. In the present invention, the principle of diffusion is extended from a microscopic grain to a macroscopic magnet, i.e., extended from deposition of a heavy rare-earth on the surface of a microscopic grain to deposition of the heavy rare-earth on the surface of a macroscopic magnet, and 20% or more of the core volume is not involved in the permeation. Diffusion layers having different depths can be obtained by adjusting the heat treatment temperature and time, and by means of magnetic hardening of the surface magnet, the purposes of improving the coercivity of the magnet and reducing the remanence (Br) and the maximum energy