Abstract: The initial stages of the electrocrystallization of zinc onto vitreous carbon from chloride zinc-plating solutions were investigated using linear sweep voltammetry and potential step method. It was observed that the deposition of zinc on the substrate did not under the UPD process before its overpotential deposition occurred. In the experimental conditions, the growth of the mature nuclei is controlled by the diffusion of the depositing ions to the electrode. The mechanism of nucleation evidently depends on the presence of the additives used, i.e., 3D progressive in the solutions with the additives, instead, 3D instantaneous without them.
By analyzing of the potentiostatic transients, the D value of the depositing zinc ions was estimated, and the nucleation rate constants A at different overpotentials η were obtained. lgA was found to be in direct proportion to η rather than η~(-2), which means that the so-called atomistic model is better than the classical model of nucleation in the present system.
Nuclear ...