Journal of Applied Electrochemistry, Vol.29, No.7, 829-836, 1999
Mass transfer and current efficiency for the electrodeposition of silver in fluorosilicic acid solution
The stripping and electrodeposition of silver in fluorosilicic acid solution are irreversible reactions as indicated by cyclic voltammetry. The rate constant for the intrinsic heterogeneous cathodic deposition of silver was obtained as k(C)(o) = 40.77 exp(1.88 - 29.43 E-C(o') and the diffusion coefficient of the silver ion in fluorosilicic acid solution as 5.17 x 10(-5) cm(2) s(-1). Theoretical calculations of the concentration of silver ion correlated well with experimental data. The relationship between the diffusion layer thickness and the stirring rate was also obtained. Increasing the stirring rate and temperature, and decreasing the current density and concentration of fluorosilicic acid, caused an increase in the current efficiency for silver deposition on graphite.
Keywords:POWDER