Effect of hydrodynamics on a copper-nickel alloy rotating disc electrode in a marine environment

Abstract

The impact of hydrodynamic conditions on the electrochemical corrosion behavior of a Cu90–Ni10 alloy in an artificial marine environment and a sulfide-contaminated marine environment in the absence and presence of 5-(3-aminophenyl)tetrazole (APT) is discussed. Electrochemical impedance spectroscopy, potentiodynamic polarization and cyclic voltammetry (CV) and surface analytical techniques, viz., X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), are applied to evaluate the APT performance. Both the R_ct and R_film values are reduced with an increase in the rotation speed in sulfide-polluted marine water and without APT. Interestingly, in the presence of APT, in the absence and presence of sulfide, both the R_ct and R_film values are increased enormously. Potentiodynamic polarization studies suggest that APT performs as a mixed inhibitor. XRD and XPS techniques suggest the presence of CuO, Cu₂O, CuCl, CuS and Cu₂S in seawater and sulfide-contaminated seawater in the absence of APT. However, the above products are completely absent in the presence of APT film.