Improvement of the thermal stability of sintered Nd-Fe-B magnets by intergranular addition of Pr 34.4 Co 65.6

Due to excellent magnetic properties, sintered Nd-Fe-B magnets have been used in various fields for many years [1, 2]. However, Nd-Fe-B magnets show a relatively low temperature stability of performance which is a main disadvantage for the application in some special cases. In order to improve the temperature stability of performance, Co, Dy and Tb elements have been added to the Nd-Fe-B sintered magnets [2, 3]. It should be pointed out that the addition of heavy rare earth (Tb, Dy) leads to a drastic reduction of the saturation magnetization. In the present work, Pr 34.4 Co 65.6 alloy powder was blended with Nd-Fe-B master alloy powder using dual-alloy method. The effects of Pr 34.4 Co 65.6 powder on the thermal stability of properties and the microstructure were investigated in details.