Striated Zinc Electrodeposition at Rotating Disk and Hemisphere Electrodes

Abstract

Zinc electrodeposition at rotating disk or hemisphere electrodes results in spiral markings which follow the stream‐lines of the laminar flow in the vicinity of the rotating surface. The angles of the striated spirals and their mathematical descriptions agree well with the theoretical angles predicted from the hydrodynamic solutions at the limit of zero distance from the wall. The markings, initiated due to small perturbations on the rotating surface during zinc electrodeposition, can serve as a visualization technique for a flow at a close vicinity to a solid boundary. A plausible explanation for the formation of striated deposits, based on a multiple steady‐state mechanism coupled with diffusion, is proposed and discussed in light of the visual observations and the experimental dependence of the striation density on the square root of the applied current density.