Magnetic Properties, Corrosion Resistance and Crystallization Behavior of Nd-Fe-B Alloys

The microstructure and magnetic properties of the over-quenching (OQ), over-quenching followed by annealing and optimum direct quenching (DQ) for the Nd11Fe83B6 alloys are studied. It is shown that the OQ + annealed α-Fe/Nd2Fe14B alloy possesses a smaller and homogeneity nanocrystal microstructure, compared to the optimum DQ α-Fe/Nd2Fe14B alloy. Meanwhile, the proper OQ + annealed is optimal to enhance the corrosion resistance and the magnetic properties (Mr = 87.44 emu/g, Hcj = 329 kA/m, (BH)max = 64.42 kJ/m3) of the α-Fe/Nd2Fe14B nanocomposite alloys. The apparent activation energies Ec(x) of crystallization for Nd2Fe14B and α-Fe phase show that nucleation is difficult and growth is easy in the process of amorphous crystallization for the over-quenching (OQ) alloy.