Deposit structure and kinetic behavior of metal electrodeposition under enhanced gravity-induced convection

Gravity-induced convection has significant effect on mass transport during metal electrodeposition. The effects of gravity-induced convection on deposit structure and kinetic behavior of metal electrodeposition were studied. It was found that copper powders and copper foils were easily electrodeposited by inhibiting and enhancing gravity-induced convection, respectively. Current efficiency was also increased from 31.5% to 92.7% due to enhancing gravity-induced convection. Double logarithm relationships between limiting current density (id) and gravity coefficient (G) for both copper and nickel electrodeposition were obtained at various metal ion concentrations. It was confirmed that diffusion coefficient was about 2.25-3.47 x 10(-6) cm(2) s(-1) and almost independent on gravity acceleration. However, diffusion layer thickness of copper electrodeposition in 0.01 M CuSO4 solution was only 0.82 x 10(-2) cm under G value of 354 due to larger flow velocity, and was much lower than that under normal gravity condition (3.41 x 10(-2) cm). Therefore, mass transport of metal electrodeposition was promoted and limiting current density was enlarged by enhancing gravity-induced convection. (C) 2015 Elsevier B.V. All rights reserved.