Formation of Disperse Silver Deposits by the Electrodeposition Processes at High Overpotentials

Abstract

In this study, electrodeposition of silver from nitrate solution at the high overpotentials was analyzed. Morphologies of silver deposits obtained at the different overpotentials and with the different electrodeposition times were examined using the technique of scanning electron microscopy (SEM). The different disperse morphological forms, such as granules, needle-like and spongy-dendritic ones were formed during silver electrodeposition from this solution. The size of granules decreased and their number increased with the increase of overpotential of electrodeposition. With the increasing overpotential, the induction time for the appearance of spongy-dendritic forms decreased with a tendency to increase their ramification. Mathematic model describing the mechanism of metal electrodeposition at the high overpotentials is proposed and discussed on the basis of the obtained silver surface morphology.