Magnetic Characteristics of Ni–Fe–Nb Alloys

Ni–Fe–Nb alloys composed of 72.98∼84.67% Ni, 6.57∼24.36% Fe and 2.43∼13.90% Nb were melted in air and reduced to ring-shaped specimens. The specimens were heated in pure hydrogen atmosphere at 1100°C for 3 hr and then cooled at various rates. Measurements of their magnetic properties, electrical resistivity and hardness indicate that the addition of niobium to Ni–Fe alloys brings about a great improvement in the characteristics of the alloys. The highest values of 42300 in initial permeability and 179000 in maximum permeability are obtained when the alloy of 79.56% Ni, 12.04% Fe and 8.40% Nb and the alloy of 79.62% Ni, 11.05% Fe and 9.33% Nb are cooled from a temperature above the order-disorder transformation point at a rate of 240°C/hr, respectively. These alloys show the coercive forces of 0.0107 and 0.0112 Oe for the maximum magnetic induction of 5000 G, respectively. The magnetic inductions of these alloys in the effective magnetic field of 1000 Oe are shown to be 6550 and 5690 G, respectively. The electrical resistivity of the latter alloy are 69.5 μΩ cm, with the Vickers hardness of 215.