Microstructure refinement and magnetic properties enhancement of nanocrystalline Nd12.3Fe81.7B6.0 ribbons by addition of Zr

Effects of Zr addition and annealing treatment on the formation, microstructure and magnetic properties of Nd12.3Fe81.7-x Zr (x) B-6.0 (x=0-3.0) ribbons melt-spun and annealed have been systematically investigated by means of vibrating sample magnetometer (VSM), differential scanning calorimeter (DSC), X-ray diffraction (XRD), and high resolution scanning electron microscopy (HRSEM). Phase analysis reveals that Nd2Fe14B is single-phase material. It has been found that the intrinsic coercivity H (ci) of the optimally processed Nd12.3Fe81.7-x Zr (x) B-6.0 ribbons increases monotonically from 751.7 kA/m for x=0 to 1005.3 kA/m for x=3.0. The remanence polarization J (r) and maximum energy product (BH)(max) increase first with Zr addition, then slightly decrease with further increasing Zr content. Optimum magnetic properties with J (r)=1.041 T, H (ci)=887.5 kA/m and (BH)(max)=175.2 kJ/m(3) have been achieved for the ribbons with x=1.5. The significant improvement of magnetic properties originates from the finer grains of the ribbons by introducing Zr.