Nucleation and early stages of growth of lead onto copper electrodes from dilute electrolytes

The processes of nucleation and growth of lead from the dilute electrolytes on copper substrates were investigated by chronoamperometry and by scanning electron microscopic (SEM) analysis of the deposits obtained in the potentiostatic regime of electrolysis. In the dependence of electrodeposition conditions, the nucleation of Pb followed either progressive or instantaneous type. The type of nucleation changed from progressive to instantaneous one with increasing the concentration of Pb(II) ions and the overpotential of electrodeposition. Regardless of the type nucleation, a novel type of Pb particles like cobweb was formed by the potentiostatic electrodeposition in the moment of nucleation and at the early stages of growth. On the basis of the shape of cobweb-like particles and the electrodeposition conditions leading to their formation, these particles were situated in the group of spongy-like ones. Also, comparative morphological analysis of Pb deposits obtained in the conditions of progressive and instantaneous nucleation confirmed the existence of two limiting types of nucleation.