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_16.5Fe₇₇B_6.5 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 Nd_16.5Fe₇₇B_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 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.

Fig. 4 The dependences of coercivity H_c, remanence B_r and maximum energy product (BH)_max of the added magnets on various fractions of Dy₃₀Nd₁₇Pr₃Al₄₀Cu₁₀.