Grain boundary diffusion material, R-T-B magnet and preparation method of R-T-B magnet

The invention discloses a grain boundary diffusion material, an R-T-B magnet and a preparation method of the R-T-B magnet. The grain boundary diffusion material comprises a diffusion substrate and a diffusion source, the diffusion matrix comprises the following components: 28.5-33.5 wt.% of R, wherein R is a rare earth element; % of Ga: 0 to 0.5 wt.%; b: 0.9 to 1.02 wt.%; 65 to 70 wt.% of Fe; the diffusion source comprises the following components: 0-70 wt.% but not 0 wt.% of HR; the HR is a heavy rare earth element and comprises Dy and/or Tb; ga > = 10 wt.%; 0 to 10 wt.% of Cu; 0 to 10 wt.% of Co; 0 to 8 wt.% of Al; and 0-8 wt.% of Fe. Compared with a diffusion matrix before grain boundary diffusion, an R-T-B magnet prepared from the grain boundary diffusion material has the advantages that the coercive force and the temperature stability are remarkably improved, and the residual magnetism is basically unchanged. 本发明公开了一种晶界扩散材料、R-T-B磁体及其制备方法。该晶界扩散材料包括扩散基体和扩散源；扩散基体包括以下组分：R：28.5～33.5wt.％，R为稀土元素；Ga：0～0.5wt.％；B：