RFeB-BASED MAGNET PRODUCTION METHOD, RFeB-BASED MAGNET, AND COATING MATERIAL FOR GRAIN BOUNDARY DI

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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 RL2Fe14B system magnet which is a sintered magnet or a hot-deformed magnet containing, as the main rare-earth element, a light rare-earth element RL 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 RL2Fe14B system magnet, a coating material 10 prepared by mixing a silicone grease 11 and an RH-containing powder 14 containing a heavy rare-earth element RH 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 RH into the grain boundaries of the base material M, whereby the coercivity is increased.