MORPHOLOGY AND STRUCTURE OF NICKEL NUCLEI AS A FUNCTION OF THE CONDITIONS OF ELECTRODEPOSITION

A study of nickel nuclei deposited on a vitreous carbon electrode from chloride baths was performed at several pH values (1 < pH < 4.5). The effects of growth rate (affected by the temperature and/or the nickel concentration), bath composition and deposition time (particularly at low overpotentials) on the morphology of nickel nuclei were analysed. Before coalescence and during the early stages of deposition, the morphology of the nuclei was influenced by the bath composition. When solutions with a high concentration of chloride ions were used, a characteristic star-shaped morphology was obtained which was attributed to the adsorption of chloride complexes. This morphology was related to the results obtained from impedance spectroscopy diagrams.