Preparation of Co–Ag films by direct and pulse electrochemical methods

A new electrolytic bath containing sodium perchlorate, thiourea, sodium gluconate, boric acid and silver and cobalt salts, able to favour simultaneous electrodeposition of silver and cobalt, has been developed. A systematic analysis of the effect of cobalt(II) concentration, applied deposition potential, hydrodynamic conditions and electrochemical techniques was made. From this bath, Co–Ag deposits of different composition have been prepared and characterized. Granular deposits were obtained from all the electrochemical deposition procedures tested; more compactness and uniformity were attained when the deposits were obtained by pulse plating method. Electrochemical and compositional characterizations indicated that heterogeneous cobalt–silver deposits were prepared containing some oxi- and/or hydroxylated cobalt species.