Effect of the Polarization Conditions on the Structural Properties of Zinc Dendritic Deposits

The influence of the polarization conditions on growth dynamics and structure of electrolytic zinc dendritic deposits obtained at room temperature from electrolyte with 0.3 mol/l zinc oxide and 4 mol/l sodium hydroxide is studied. The electrodeposition was performed at constant and pulsed current and potential. Constant-current chronopotentiometry was used to determine the surface area of the dendritic deposits in situ. The zinc microstructure was studied with electron microscopy. The deposit surface produced in pulsed current conditions intensively grew during the first 5 minutes of electrolysis and then changed insignificantly. In conditions of potentiostatic electrolysis, the coefficient K, which is the ratio of the deposit surface area to the substrate area, increased linearly with time; in pulsed potential conditions, it increased as a power-law functions. The deposits obtained in potentiostatic conditions show the lowest density that slightly varies with thickness. The density of the deposits crystallized in pulsed current conditions sharply increased upon the completion of active dendrite extension.