Improvement of the Magnetic Properties of Nanocrystalline Nd 12.3

Nd12.3−xDyxFe81.7Zr0.8Nb0.8Cu0.4B6.0  (x=0–2.5) ribbons have been prepared by melt-spun at 30 m/s and subsequent annealing. The influence of addition of Dy on the crystallization behavior, magnetic properties, and microstructure were investigated. Differential scanning calorimeter (DSC) and X-ray diffraction (XRD) revealed a single-phase material. Microstructure studies using transmission electron microscopy (TEM) had shown a significant microstructure refinement with Dy addition. Wohlfarth’s analysis showed that the exchange coupling interactions increased first with Dy content x increasing, reached the maximum value at x=0.5, and then slightly decreased with x further increasing. Optimal magnetic properties with Jr=1.09 T, Hci=1048 kA/m, and BHmax=169.5 kJ/m3 are achieved by annealing the melt-spun ribbons with x=0.5 at% at 700°C for 10 min