Effect of pulsed magnetic field treatment on the magnetic properties for nanocomposite Nd2Fe14B/α-Fe alloys

Nanocomposite alloys with the compositions of Nd8.5Fe77.6−xCo5Zr2.7GaxB6.2 (x = 0, 0.3, 0.6, 0.8, 1.0) were prepared by melt spinning. It was found that a small amount of 0.6 at.% Ga addition is beneficial to improve the hard magnetic properties of the alloy. The melt-spun Nd8.5Fe77Co5Zr2.7Ga0.6B6.2 ribbons were annealed in a pulsed magnetic field. The results revealed that the remanence Jr and the maximum energy product (BH)max were obviously improved when annealed below the Curie temperature of the alloy. The best magnetic properties of Jr = 0.975 T, iHc = 582 kA/m, and (BH)max = 131 kJ/m3 were obtained for the ribbons annealed at 300 °C in a pulsed magnetic field. The (BH)max was enhanced by 23.8% compared with that of the ribbons without magnetic annealing. It provides a new way to improve the magnetic properties of permanent magnets produced by pulsed magnetic annealing at temperatures below the Curie point of the alloys.