Method for improving sintered nd-fe-b magnet crystal boundary

The invention discloses a method for improving the sintered nd-fe-b magnet crystal boundary. The method includes the following specific operation steps that 1, nd-fe-b powder is prepared through a conventional method; 2, a sort of metal or alloy powder M is collected, and surface fluorinated treatment is conducted on the powder M; 3, the surface-fluorinated powder is doped into the nd-fe-b powder through a double-alloy method; 4, the evenly-mixed powder is sintered after being formed and pressed, a sintered sample is then subjected to annealing treatment, and accordingly a sintered nd-fe-b magnet is obtained. The method has the advantages that on one hand, F elements are aptly added in the crystal boundary, accordingly, an ordered NdOF phase can be generated, and thus the coercivity of the magnet is improved; on the other hand, the exchange coupling action between crystals is weakened by adding the F elements; furthermore, the lattice deformation thickness can be effectively reduced by adding the F elements, and the coercivity of the magnet can be effectively improved as well.