Influence of chloride on the long-term interaction of copper with deoxygenated neutral aqueous solutions

• Corrosion potential, impedance and soluble copper concentration monitored for 3000 h in borate buffer containing NaCl.
• Corrosion potential close to the CuCl2-/Cu equilibrium potential.
• No corrosion layer detected by voltammetry, soluble copper concentration reaches steady state.
• Experimental data reproduced by a model featuring CuOH and CuCl intermediates.

The evolution of open-circuit potential, soluble copper concentration and impedance during immersion of Cu in deoxygenated neutral borate buffer containing 0.01–1.0 mol l−1 NaCl was monitored for up to 3000 h. The open-circuit potential was found to be close to the CuCl2-/Cu equilibrium potential. No corrosion layer was detected by voltammetric scans and the soluble copper concentration reached a steady state. Experimental data were quantitatively interpreted by a kinetic model featuring CuOH and CuCl intermediates. The process through which the system reached steady state is tentatively related to a reaction that could lead to hydrogen evolution.