Effects of Deposition Conditions on the Morphology of Zinc Deposits from Alkaline Zincate Solutions

The morphology of zinc deposits from alkaline zincate solutions was systematically investigated over a wide range of conditions. Zinc deposit morphology was categorized as heavy spongy, dendritic, boulder, layerlike, and filamentous mossy. The formation of dendritic, layerlike, and mossy deposits is under single-factor control, and these morphologies are defined as type I. The formation of heavy spongy and boulder deposits is under multiple-factor control, and they are defined as type II. Within type I, dendrite initiation and growth are both under diffusion control, while layer and mossy formation is under activation control. Based on the effects of deposition conditions, morphology diagrams were constructed. These diagrams demonstrate that the control factors are not independent, and no universal critical overpotential for a specific deposit morphology exists.