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

In this work, microstructure and magnetic properties of sintered Nd16.5Fe77B6.5 magnets with intergranular addition of Dy30Nd17Pr3Al40Cu10 were investigated. The additional particles with size in the range of 1–2 µm were homogeneously mixed into micrometer Nd16.5Fe77B6.5 master powder with different weight fractions. The investigation shows that coercivity Hc of the added magnets significantly increases, while their remanence Br decreases with increasing Dy30Nd17Pr3Al40Cu10 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 Dy30Nd17Pr3Al40Cu10 compound to grain boundary, the Dy concentration can be reduced by 60 wt.% in comparison with the conventional method.