RFEB-BASED MAGNET PRODUCTION METHOD, AND COATING MATERIAL FOR GRAIN BOUNDARY DIFFUSION PROCESS

The present invention addresses the problem of providing a method for producing an RFeB system magnet with high coercivity by preventing a coating material from peeling off the surface of a base material during a grain boundary diffusion treatment. Provided is a method for producing an R L 2 Fe 14 B system magnet which is a sintered magnet or a hot-deformed magnet containing, as the main rare-earth element, a light rare-earth element R L which is at least one of the two elements ofNd and Pr, the method including the steps of: applying, to a surface of a base material M of the R L 2 Fe 14 B system magnet, a coating material 10 prepared by mixing a silicone grease 11 and an R H -containing powder 14 containing a heavy rare-earth element R H composed of at least one element selected from the group of Dy, Tb and Ho; and heating the base material M together with the coating material. The silicone having a siloxane bond prevents the coating material 10 from peeling off the surface of the base material M during the heating process. The improved adhesion of the coating material 10 to the base material M facilitates transfer of R H into the grain boundaries of the base material M, whereby the coercivity is increased.