INVESTIGATION OF THE ELECTROCHEMICAL OXIDATION OF COPPER IN MOLTEN NH4HF2-HF

The electrochemical behavior of copper in an hydrous 1.37HF-NH4HF2 mix ture was investigated at 25-degrees-C using voltammetric and electroch emical impedance spectroscopic techniques. A reference electrode based on a copper electrochemical system was conceived and realized to allo w the electrochemical measurements to be performed accurately. The rea ction mechanisms are complex and the experimental results can be, in a first approach, interpreted by considering the occurrence of adsorbed species and fluoride and oxide compounds of copper at oxidation state s I and II. Passivation processes were shown and electrical equivalent circuits proposed for accounting for the experimental results.