Electrodeposition of silver-bismuth alloys from thiocyanate-tartrate electrolytes investigated by cyclic voltammetry

The electrochemical processes during the deposition and dissolution of Ag-Bi alloys from alkaline thiocyanate-tartrate electrolytes have been investigated by cyclic voltammetry. Two cathodic reactions during the deposition of the alloy and two anodic ones during its dissolution are observed. Bismuth is electrodeposited on silver coating deposited at more positive potentials. The dissolution reactions of Bi and Ag from the coating are well-distinguished and about 0.5 V apart from each other. The effects of the concentration of both metals in the electrolyte and the potential sweep rate upon the electrode processes are shown. The deposition conditions when the electrochemical process is carried out under diffusion control are established. The results of the investigation could be useful for the formulation of Ag-Bi alloy plating electrolytes.