Electrodeposition of disperse non-dendritic zinc on foreign substrates

Attempts have been made to define the conditions leading to the formation of granular zinc deposits from alkaline zincate and zinc sulphate solutions on nickel. Neither constant potential step nor the double pulse potentiostatic method produced visible individual grains. This was found to be due to the fact that at sufficiently low overpotentials the grain growth becomes inhibited for unknown reason before it becomes visible under the optical microscope, while at high overpotentials the large numbers of nuclei formed, lead to fine-grained compact deposits. The development of a small number of discernible grains not increasing in number but increasing in size was achieved in several instances by using a pulsating overpotential. A criterion for estimating the coarseness of the deposit before its grains become visible was found in the quantity of charge needed for the deposit to be seen. Using this criterion, the dependence of the coarseness on the parameters of pulsation has been investigated.