Effect of Fe/Ni ratio on amorphization, crystallization kinetics, and magnetic properties of FeNiSiBCuNb alloys

•Non-isothermal crystallization kinetics behavior of FeNiSiBCuNb amorphous ribbon was studied.•Increasing or decreasing the annealing cooling rate will deteriorate the soft magnetic properties.•Excellent magnetic properties containing of low coercivity (Hc) and high permeability (μe) FeNi-based alloys were successfully obtained. In this work, the precipitation phase transformation, crystallization kinetics, and soft magnetic properties of (FexNi80-xSi9.5B9.5Cu1)0.97Nb0.03 (x = 36, 38, 40, 42, 44) alloys have been investigated systematically. It was found that the partial substitution of Fe for Ni can enhance the GFA, increasing the Trg from 0.507 to 0.527 for the best-performing alloy. With increasing annealing temperature, less α-Fe(Si), and more (Fe,Ni)Si and (Fe,Ni)B phase precipitates. The crystallization kinetics show that the peak temperature of the secondary phase transformation (α-Fe(Si)→γ(Fe,Ni)Si) is less sensitive to the heating rate. It is also found that structural relaxation of the amorphous system and consequential release of internal stress results in a decrease in Hc and an increase in µe. The minimum Hc values and maximum µe values for the alloys with x = 36, 38, 40, 42, and 44 were 0.14 A/m, 0.11 A/m, 0.23 A/m, 0.08 A/m, and 0.03 A/m, and 17,000, 14,600, 10,800, 12,700, and 16,500, respectively.