Method for preparing high-performance bulk neodymium-iron-boron magnet through grain boundary diffusion

The invention discloses a method for preparing a high-performance bulk neodymium-iron-boron magnet through grain boundary diffusion. One coating surface of each sheet neodymium iron boron magnet is coated with an RxMy alloy film layer; the other coating surface is coated with a GaFb alloy film layer; a plurality of thin neodymium-iron-boron magnets coated with the RxMy alloy film layers and the GaFb alloy film layers are attached and arranged at intervals in the thickness direction to obtain a laminated parison; and in a vacuum environment or an inert gas protection environment, the laminatedparison is subjected to heat treatment to obtain a high-performance large neodymium-iron-boron magnet, and in the heat treatment process, element mutual diffusion occurs between each thin neodymium-iron-boron magnet and the RxMy alloy film layer and the GaFb alloy film layer coating the thin neodymium-iron-boron magnet to form a transition layer. The method has the advantages that the limitation of the grain boundary diff