Method for preparing R-Fe-B series sintered magnets

The invention relates to a method for preparing R-Fe-B series sintered magnets. The method for preparing the R-Fe-B series sintered magnets comprises the steps that firstly a conventional method is utilized to prepare the R-Fe-B series sintered magnets which are 1-10 millimeters in thickness; then, a thermal spraying method is utilized to spray metal Tb or metal Dy which is 10-200 micrometers in thickness on the surfaces of the R-Fe-B series sintered magnets in a sealing box under the protective atmosphere of Ar gas; finally the sintered magnets are placed in a vacuum sintering furnace, the surfaces of the sintered magnets are sprayed with the metal Tb or the metal Dy, under the vacuum atmosphere or the protective atmosphere of the Ar gas, thermal treatment is conducted on the sintered magnets under temperature of 750-1000 DEG C, so that a heavy rare earth element Tb or a heavy rare earth element Dy enters the interiors of the sintered magnets. According to the method for preparing the R-Fe-B series sintered magnets, the thermal spraying method is utilized to spray a layer of Tb or Dy on the surfaces of the sintered magnets, treating speed is high, coatings are uniform, yield is high, and coercivity of the sintered magnets is greatly improved after thermal treatment.