Electrochemical behavior of annealed soft-magnetic FeSiBPCu alloy

The nanocrystalline soft-magnetic Fe_83.3Si₃B ₁₀P₃Cu_0.7 ribbon alloy with a width of 10mm prepared through annealing amorphous Fe_83.3Si₃B ₁₀P₃Cu_0.7 ribbon alloy at 698K had a saturation magnetization flux density of 1.82 T and a coercivity of 11.8Am^-1. The nanoheteroamorphous microstructure consisted of -Fe nanocrystals with an average size of 22nm and amorphous neighbor phases. The results of polarization curves and electrochemical impedance spectra obtained in 0.5M Na ₂SO₄ and 0.5M NaCl solutions demonstrated the positive shift of the corrosion potentials, the decrease in the passive current density, the increase in the breakdown potentials and the increase in the polarization resistance for the nanocrystalline Fe_83.3Si₃B ₁₀P₃Cu_0.7 ribbon alloy, compared with its amorphous counterpart alloy. The corrosion performance was improved via annealing, which is thought to result from the enrichment of B₂O ₃ constituent in the surface oxide layer.