Magnetic Properties of Ni-Fe-Nb Alloys

Measurements of magnetic properties, electrical resistivity and hardness have been carried out for Ni-Fe-Nb alloys of 72.98∼84.67%Ni, 6.59∼24.36%Fe and 2.43∼13.90%Nb heated in pure hydrogen atmosphere at 1100°C for 3 hr and then cooled at various rates. It is shown that the addition of Nb exceedingly improves the magnetic properties of Ni-Fe alloys. The highest values of 42300 in initial permeability and 179000 in maximum permeability are shown by the compositions of 79.56%Ni, 12.04%Fe and 8.40%Nb and of 79.62%Ni, 11.05%Fe and 9.33%Nb when cooled from a temperature above the order-disorder transformation point at a rate of 240°C/hr, respectively. The coercive forces of these two alloys for a maximum magnetic induction of 5000 G are 0.0107 and 0.0112 Oe, respectively, and the magnetic inductions in an effective magnetic field of 1000 Oe are 6550 and 5690 G, respectively. The electrical resistivity and Vickers hardness of the latter alloy are 69.5 μΩ-cm and 215, respectively.