HIGH-COERCIVITY NEODYMIUM IRON BORON MAGNET AND PREPARATION METHOD THEREFOR

摘要

The present invention belongs to the field of permanent magnet materials, and discloses a high-coercivity neodymium iron boron magnet and a method for preparing same. First, a low-melting-point non-rare-earth alloy having a melting point of 450°C to 950°C is prepared; a surface diffusion medium is then placed onto the surface of the neodymium iron boron magnet to form a diffusion couple, or a metal oxide film is magnetron-sputtered onto a neodymium iron boron substrate as a surface diffusion medium; finally, the described neodymium iron boron magnet is subjected to diffusion heat treatment in a vacuum to obtain a high-coercivity neodymium iron boron magnet. The surface diffusion process of the present invention is simple and effective and does not use rare-earth alloys or compounds as diffusion media; on the basis of significantly reducing the content of rare-earth elements in neodymium iron boron magnets, it is possible to effectively improve the distribution of the grain boundary phase of a magnetic body, significantly increasing the coercivity of the magnet.