ELECTROCHEMICAL-BEHAVIOR OF COPPER ELECTRODE IN CONCENTRATED SULFURIC-ACID-SOLUTIONS

The electrochemical behaviour of copper in 6.0 mol l-1 sulfuric acid at 30-degrees-C, was studied by means of the potentiodynamic method. At low potential sweep rates, v < 200 mV s-1, the data reveal that the anodic process is basically constituted of copper dissolution and a film formation which inhibits further metal oxidation and which may undergo further dissolution. For higher potential sweep rates, a modification in the passivation region of the voltammogram is observed. It can be ascribed to a change in the passivation mechanism which possibly involves different surface species. The kinetic relationships derived from the potentiodynamic I/E curves obtained at low v suggest a film formation via a dissolution/precipitation mechanism.