COPPER ELECTRODEPOSITION AND DISSOLUTION AT ELECTRODES MODIFIED IN ADVANCE WITH THIOUREA

The cathodic and anodic behavior of copper electrodes modified in adva nce by immersion into an acidic sulfate copper bath with thiourea was studied in the same electrolyte without thiourea as well as in sulfuri c acid solution. Two types of adsorbed film were found to be formed wh ich had different inhibiting effects on copper electrodeposition and d issolution and on hydrogen ion discharge. The behavior of these films was studied, and suggestions as to their composition were made. It was found when using adsorbed layers which are lifted by the metal that w ithout an incorporation of the additives into the deposits, the struct ure of the coatings is independent of overpotential.