Electrochemical studies of pitting corrosion of Cu-Fe alloy in sodium chloride solutions

The electrochemical studies of pitting corrosion of Cu-Fe alloy (70% Cu-30% Fe) were carried out in sodium chloride solutions. The techiniques of measurements were: open-circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy. The effect of different concentrations of the inorganic additives (WO42-, PO43-, NO2-, B4O72- and CrO42-) on the pitting corrosion of the alloy in 0.5 M NaCl was also studied. It was found that the alloy underwent pitting corrosion in sodium chloride solution at definite pitting potential depending on the concentration of NaCl according to the relation: E-pit = a(1) - b(1) log CCl-. The investigated inorganic additives had inhibiting effect on the pitting corrosion of the alloy in 0.5 M NaCl and their efficiency decreases according to the order WO42- > PO43- > NO2- > B4O72- > CrO42-. (C) 2008 Elsevier B.V. All rights reserved.