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

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 Rct and Rfilm 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.