Electrochemical stability of Cu–10Al–5Ni alloy in chloride–sulfate electrolytes

The electrochemical behavior of the Cu–10Al–5Ni alloy in simulated electrolytes like those used in the industrial processes under normal working conditions was investigated. Conventional electrochemical techniques including open circuit potential measurements, polarization techniques, and electrochemical impedance spectroscopy were used. The alloy was found to be more stable against corrosion when the chloride–sulfate solution had a pH of 7–9. A sulfate concentration of ≅0.1 M in the chloride–sulfate electrolyte leads to the passivation of the alloy surface. The activation energy of the corrosion process was found to be 8 kJ mol−1 assigning a diffusion controlled reaction. The impedance measurements and impedance data fitting to equivalent circuit models have shown that the passive film posses a duplex nature.