INHIBITED ZINC ELECTRODEPOSITION - ELECTRODE-KINETICS AND DEPOSIT MORPHOLOGY

The electrode kinetics of spongy and dendritic zinc deposition were studied in the presence of three inhibitors (lead acetate, tetrabutylammonium bromide and benzalacetone). It was shown that these additives increase the cathodic overvoltage, decrease the current efficiency, eliminate multiple steady states in acid electrolytes, and modify the impedance diagrams. Such changes in electrode kinetics were interpreted in terms of weaker autocatalytic adsorption of metal cations and enhanced hydrogen adsorption. It was also shown that a pH decrease had a similar effect on these reaction rates. It was concluded from very low frequency impedance measurements that the additives give rise to an accelerated nucleation rate ensuring a faster renewal of active growth sites. © 1979 Chapman and Hall Ltd.