Electrochemical and ellipsometric study of the oxide films formed on copper in borax solution. Part II: Effect of ozone

Abstract

The influence of O₃ on the passive behaviour of copper was analysed in the potential region -0.32 to 0.70 V vs RHE in borax solutions (pH 9.2) through voltammetric techniques and ellipsometry. Oxide formation can be explained as a sequence of Cu₂O growth, Cu(II) chemisorption, and dissolution precipitation steps similar to those corresponding to copper electrodes in deaerated solutions. The role of Cu(II) chemisorption is discussed in this paper. The progressive accumulation of hydrated layers hinders the reaction between O₃ and the metal. O₂ and O₃ promote growth and dissolution processes (both at open circuit and in controlled potential experiments) but O₃ has a stronger effect.