Magnetic Properties of Resin-Bonded Magnets of Anisotropic Nd-Fe-B-Cu Powder

Anisotropic Nd-Fe-B-Cu powder was fabricated by grinding melt-spun and subsequently hot-rolled materials. We prepared two types of powder with different particle shapes: one isotropic shape, and the other a flat shape with the c-axis perpendicular to the flat face. Perpendicular-field pressing experiments show that isotropic particles are better aligned in the bonded magnet than are flat particles. Radial-field pressing using isotropic particles yields high (BH)max values of up to 16 MGOe for bonded magnets with a density of 6.0 g/cm³. Nd-Fe-B-Cu powder has been found to be well aligned in a relatively weak magnetic field. This fact is useful when fabricating ring magnets with larger height to diameter aspect ratios.