Influence Of Magnetic Field Annealing On Magnetic Properties For Soft Magnetic Alloys

Amorphous ribbons with nominal composition of(Fe_1-xCo_x)_73.5Si_13.5B₉Nb₃Cu₁?x=0.25, 0.5, 0.75?, Fe₅Co₅₈Ni₁₀Si₁₁B₁₆, Fe₅Co₇₀Si₁₅B₁₀, Fe₆₅Co₁₅Si₅B₁₅ were prepared by single roller wheel melt spinning. We mainly explored that the influence of magnetic field annealing on soft magnetic properties for the above alloys. In order to estimate magnetic response of alloys, the saturation magnetostriction ?s, effective magnetic anisotropy <K> as well as temperature dependence of initial permeability??i-T curves? were investigated.For nanocrystalline(Fe_1-xCo_x)_73.5Si_13.5B₉Nb₃Cu₁?x=0.25, 0.5, 0.75? alloys,different magnetic field annealing methods were applied to the thermal treatment process of alloys,such as direct magnetic field nanocrystallization and magnetic field reannealing after nonmagnetic field nanocrystallization. These magnetic field annealing methods can significantly improve the ?i of Fe Co-based experimental samples, but the impact degree is significantly different. After magnetic field annealing, the ?s was reduced and the <K> was enhanced, which can contribute to the increase of ?i. Compared with magnetic field reannealing after nonmagnetic field nanocrystallization, magnetic field nanocrystallization can more effectively improve soft magnetic properties of alloys, which could be attributed to a stronger ferromagnetic atomic mobility in the early period of primary crystallization.For amorphous Fe₅Co₅₈Ni₁₀Si₁₁B₁₆, Fe₅Co₇₀Si₁₅B₁₀, Fe₆₅Co₁₅Si₅B₁₅ alloys, the increase of magnetic field annealing temperature can contribute to more significant impact of magnetic field on magnetic softness, which is ascribed to the enhancement of ferromagnetic atomic mobility. As magnetic field annealing temperature exceeds the crystallization temperature, the soft magnetic properties of alloys dramatically worsen, which is due to the existence of large magnetocrystalline anisotropy K1 after adequate crystallization. In this case, magnetic field annealing can hardly improve the soft magnetic properties.