Properties of Ultrafine Crystalline (Fe-Cu1-Nb3)-Si-B Quasi-Ternary Alloys and Improvement of Their Magnetic Properties by Magnetic Field Annealing

The influence of the Si and B contents and of magnetic field annealing on the magnetic properties of ultrafine crystalline (Fe-Cu1-Nb3)-Si-B quasi-ternary alloys were studied. An alloy containing 13.5 at% Si and 9 at% B exhibited the best soft magnetic properties. The relative permeability of this alloy at 1 kHz is about 1 × 10⁵. On the other hand, alloys containing about 2 at% Si and 13 at% B show a high flux density of about 1.55 T, and those containing about 17 at% Si and 5 at% B have nearly zero magnetostriction. Magnetic field annealing is very effective for improving the hysteresis curves of these alloys for many applications.