Electrochemical studies with copper-based alloys: open-circuit potential oscillations in alkaline media

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In open-circuit potential measurements of certain Cu-based alloys in NaOH solutions oscillations were observed in Cu-Al and Cu-Ag-Al. Studies with various electrolyte concentrations and rotation speeds of the electrode led to a possible explanation of the phenomenon in terms of Al dissolution altering the main Cu dissolution/passivation process. The accumulation of aluminate ions on the interphase and its transportation to the bulk solution are the main causes of the oscillations.