Use of a rotating cylinder electrode in corrosion studies of a 90/10 Cu-Ni alloy in 0.5 mol L-1 H2SO4 media

The corrosion of 90/10 Cu-Ni alloy in deaerated 0.5 mol L-1 H2SO4 containing Fe(III) ions as oxidant and benzotriazole as inhibitor was studied using a rotating cylinder electrode (RCE). Nonselective dissolution was observed in all experimental conditions investigated. In the absence of Fe(III) ions, the anodic process is diffusion controlled while cathodic process is charge transfer controlled. In contrast, with Fe(III) ions as oxidant, the cathodic process is controlled by diffusion and the anodic process is under charge transfer control. These conclusions were obtained from measurements of open circuit potential as a function of the RCE rotation rate as previously verified for the RDE. Inhibition efficiency evaluated from weight loss and calculated from polarization curves showed good agreement.