Granular growth of electrochemically deposited metals

Abstract

Conditions of deposition of cadmium from cadmium perchlorate solutions on copper electrodes, leading to the appearance of granular deposit (boulders), have been investigated. It was found that this type of deposit appears in a limited pH range only (pH 3 to 6) in which colloidal cadmium hydroxide is found to appear. The probability of appearance of granules is different at different crystal planes of the copper substrate. The rate of growth of the granules has been determined microscopically. It was found that the size of the granules increases proportionally to the square root of time. This indicates that the rate of growth is controlled by the spherical diffusion of depositing ions from the bulk of solution.