Magnetic Properties of the Fe_63.5Ni₁₀Cu₁Nb₃Si_13.5B₉ Alloy Nanocrystallized in the Presence of Tensile Stresses

The effect of 10 at % Ni, which was introduced into the classic Finemet Fe_73.5Cu₁Nb₃Si_13.5B₉ at the expense of the Fe content, on the magnetic properties of the composition has been considered. The alloy was subjected to nanocrystallizing annealing in the presence of tensile stresses and in their absence. It is shown that, similarly to the Ni-free alloy, in the Fe_63.5Ni₁₀Cu₁Nb₃Si_13.5B₉ alloy subjected to thermomechanical treatment, the magnetic anisotropy with the easy magnetization direction across the ribbon axis (transverse induced magnetic anisotropy) is induced. It was found that the 10 at % Ni addition almost does not affect the value of magnetic anisotropy constant induced under thermomechanical treatment and decelerates the process of magnetic anisotropy inducing at σ ≤ 200 MPa. The Ni-containing alloy subjected to nanocrystallizing annealing (at 520°C) in the presence of tensile stresses and in their absence demonstrates the more than 200-fold increase in the coercive force as the annealing time increases from 1 to 4 h, whereas the coercive force of the Ni-free alloy is almost unchanged. This is likely to be related to the appearance of new structural components in the Ni-alloyed composition upon annealing.