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

In this work, the precipitation phase transformation, crystallization kinetics, and soft magnetic properties of (Fe _xNi _{80- x}Si _9.5B _9.5Cu ₁) _0.97Nb _0.03 ( 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 T _rg 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 H _c and an increase in µ _e. The minimum H _c values and maximum µ _e 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.