The invention discloses a method for enhancing the coercive force of a
neodymium-iron-
boron magnet through
evaporation grain boundary diffusion, and belongs to the technical field of magnetic materials. The method comprises the specific technical steps that a
neodymium-iron-
boron orientated compact is subjected to vacuum pre-
sintering, and a pre-sintered compact is obtained;
rare earth and
alloy elements are subjected to
evaporation deposition to be in a form of ionized atoms / molecules and are diffused into the
neodymium-iron-
boron pre-sintered compact through pores of the pre-sintered compact, subsequently, the
rare earth and
alloy elements are densified through
microwave sintering, and
grain boundary diffusion is generated, so that the
grain boundary structure of the
magnet is improved,and the coercive force of sintered neodymium-iron-boron is improved. The method has the advantages that the
rare earth and
alloy elements as a
diffusion source are in the form of gas-phase atoms / molecules, compared with a
liquid diffusion source, the elements can more uniformly, effectively and deeply permeate into the
magnet, and the periphery of the neodymium-iron-boron main phase is coated withthe elements; through testing, the coercive force of the neodymium-iron-boron magnet product obtained through gas-phase grain boundary diffusion can be increased by 30% or above, the diffusion depthcan reach 6 mm, and the neodymium-iron-boron magnet product has no
hydrogen or
fluorine generated through liquid-
phase diffusion.