Effects of diffusion limitation and non-diffusion limitation on the morphology of silver by electrodeposition

Silver aggregation was eletrodeposited on silicon plate in silver nitrate aqueous solution and observed by TEM and SEM. It is found that the morphology of silver deposition transform from polyhedron to dendrite structure with the voltage increasing. Different kinetic factors control the different growth processes and can be divided into three kinetic regions according to the polarization curve: the electrochemical reaction; the diffusion limitation; and the competition of reaction and diffusion. In first field, the kinetic of crystal growth controlled the all deposition process. In second field, the kinetic of diffusion limitation controlled the process. The silver precipitates have different morphologies in the three regions according to the SEM observation. This paper analyzes the different deposition processes in the three fields and how the kinetic factor influences the shape.