Coercivity Enhancement of Sintered Nd–Fe–B Magnets by Intergranular Adding Micro-Structured Dy–Nd–Pr–Al–Cu Powder

Abstract

In this work, microstructure and magnetic properties of sintered Nd 16.5 Fe 77 B 6.5 magnets with intergranular addition of Dy 30 Nd 17 Pr 3 Al 40 Cu 10 were investigated. The additional particles with size in the range of 12 µm were homogeneously mixed into micrometer Nd 16.5 Fe 77 B 6.5 master powder with different weight fractions. The investigation shows that coercivity H c of the added magnets significantly increases, while their remanence B r decreases with increasing Dy 30 Nd 17 Pr 3 Al 40 Cu 10 additional fraction. The coercivity of the magnets increases from 14.5 kOe to 31.5 kOe with increasing the additional fraction from 0 to 9 wt.%. By adding Dy 30 Nd 17 Pr 3 Al 40 Cu 10 compound to grain boundary, the Dy concentration can be reduced by 60 wt.% in comparison with the conventional method.