A cyclic voltammetric study of ferrocyanide-thiocyanate silver electrodeposition electrolyte

The electrochemical behaviour of ferrocyanide-thiocyanate electrolytes for silver electrodeposition was studied by cyclic voltammetry. The differences in the electrolyte preparation procedure do not affect their electrochemical behaviour at identical silver concentrations. The silver electrodeposition is characterized by two cathodic current maxima and by charge transfer limitations with a preceding chemical reaction. The dissolution of the electrodeposited silver is characterized by the formation of AgCN on the electrode and further dissolution by passivation and formation of oxide products, which are reduced during the next cathodic scan. The redox processes of iron from the ferrocyanide complex on Pt- and Ag-substrates, as well as the effect of the complex forming agents like SCN-- and CN-- ions are shown.