Electrochemical behaviour of a tin electrode in tartaric acid solutions

The electrochemical behaviour of tin in tartaric acid solutions was investigated using potentiodynamic and galvanostatic techniques. The E/I curves showed that the anodic behaviour of tin exhibits active/passive transition. In the active dissolution potential region, tin dissolves as Sn(II) species, which are subsequently oxidized to Sn(IV). The active dissolution of tin increases with increasing tartaric acid concentration, sweep rate and temperature. Passivation is due to formation of Sn(OH)4 and/or SnO2 film on the anode surface. The dissolution process is controlled by diffusion. The E/t curves displayed that the time needed to active passive transition increases with increasing acid concentration and temperature but decreases with increasing imposing anodic current density.