The Influence of tin ions on the electrodeposition of zinc
Sprache des Titels:
Tin has a strong influence on the electrodeposition of zinc already in
concentrations of less than 1 ppm. Tin changes the mechanism, the deposition rate and the morphology of the resulting surface of zinc deposited from an acidic sulfate electrolyte. These severe changes are not obvious since both elements have similar overpotentials for hydrogen evolution as the dominant side reaction. The influence on the electrodeposition of zinc was studied using cyclic voltammetry on a rotating disc electrode, chemical analysis of the zinc layers,
chronopotentiometric measurements, and investigations into the
microstructure by SEM. It is shown that tin co?deposits with zinc starting at concentrations of about 1 ppm and therefore changes the structure of the zinc layer. A mechanism is presented that explains the significant drop in current efficiency in a pulsed deposition program, in which the codepositing tin acts as cathode during the off cycle leading to drastic anodic redissolution of the zinc.