Corrosion and Passivity of Copper in Basic Solutions of Acetate Ions

Abstract

The anodic oxidation of copper in sodium acetate aqueous solutions is studied in relation to the anodic films formed, in order to elucidate the role of acetates to the corrosion of copper. At open circuit conditions a cuprous oxide layer is formed having a thickness of few monolayers. At low anodic potentials, a composition with a single component which is cuprous oxide, is observed for the thin anodic film, whereas at relatively high anodic potentials a cuprous oxide and cupric hydroxide film is formed, accompanied by extensive dissolution of anodic products. At intermediate potentials, a duplex oxide film formation is not able to explain the electro-oxidation/reduction processes on copper in acetate solutions but the presence of the conducting hydrated layer, which may be probably basic copper acetate on top of cuprous oxide layer, has to be considered.