Coercivity Enhancement of the Nd-Fe-B Sintered Magnets with Grain Boundary Diffused by Dy or Tb Element

In the present study, the enhanced magnetic properties of Nd-Fe-B sintered magnet pieces treated with the Dy or Tb metal as reduced by heating their oxides or fluorides with CaH2 are reported together with the results obtained on the samples simply coated and heated with the oxide or fluoride of Dy and Tb elements and the mechanism for enhancing the coercivity is disscussed to produced much powerful Nd-Fe-B sintered magnets.