The dissolution of copper in acidic solution containing fluoride ions has been investigated by channel flow double electrode (CFDE) and steady-state electrochemical measurements. Polarization curves of copper in the presence of fluoride ions apparently show the Tafel region, whose slope is 0.06 V/dec. The pH of the solution affects the dissolution rate at low fluoride concentrations. On the other hand, fluoride ions influence the dissolution rate at high fluoride concentrations. Using the CFDE system, cuprous and cupric ions were detected during polarization curve measurements. Both cuprous and cupric ions are found in a wide potential range, and the presence of cupric ion is explained by the disproportionation reaction which follows the surface dissolution process, forming cuprous ion. On the basis of experimental results, the active dissolution mechanisms of copper in acidic solution containing fluoride ions were proposed.
- A. copper
- B. polarization