A New Electrochemical Method for Determining the Fractal Dimension of the Surface of Rough Metal Electrodeposits: Its Application to Dendritic Silver Surfaces

The surface of dendritic Ag electrodeposits grown on nearly spherical polyfaceted Pt electrodes from 0.5M Na sub 2 SO sub 4 + 10 exp --2 M H sub 2 SO sub 4 + 0.5 x 10 exp --2 M Ag sub 2 SO sub 4 at 0.042 V, has been characterized in terms of fractal geometry by using a new procedure for determining the area (A) and the volume (V) of the electrodeposits. The area was indirectly determined from the Pb and Cd upd voltammetric charge and the volume was evaluated from the Ag electrodeposition charge. The relationship between A and V shows fractal behavior A proportional to V exp D/3 over more than one decade of V with D = 2.50 plus /minus 0.03. This figure is consistent with a random Ag dendritic surface growth limited by the electric field on the solution side around the growing tips.