Additive blending effects on the magnetic properties of nanocrystalline NdFeB magnets

Isotropic NdFeB powders were blended with pure Zn and Sn powders by planetary ball milling. The mixed powders were compacted by the current applied pressing (CA-press) process and subsequently deformed by the current applied deformation (CA-deformation) process. The coercivity of CA-pressed magnets was nearly the same regardless of milling time; however, the coercivity of CA-deformed magnets decreased with an increase of milling time. The addition of Zn or Sn at less than 1 wt% resulted in an increase of coercivity and anti-corrosion properties of the CA-pressed isotropic magnets and CA-deformed anisotropic magnets. CA-deformed NdFeB magnets with 0.3 wt% Zn or Sn addition consisted of smaller grains and showed about 80% higher coercivity than additive-free magnets. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.