Electrochemistry of tin deposition from mixed sulphate and methanesulphonate electrolyte

The electrodeposition of tin, at a copper surface, from a tin sulphate (0.014 mol dm(-3)) electrolyte containing methanesulphonic acid (12.5 vol.-%) at 295 K has been studied. Cyclic voltammetry, using potential sweep rates of 8-128 mV s(-1), at a stationary copper electrode provided information on the potential ranges for tin deposition and stripping. Linear sweep voltammetry, at a copper rotating disc electrode was used to evaluate the mass transport characteristics of the system under controlled, laminar flow conditions. The changes in the limiting current density with a Sn2+ concentration of 0.006-0.078 mol dm(-3) and an electrode rotation rate of 200-4800 rev min(-1) were quantified. Randles-Sevcik and Levich equations were used to give an averaged diffusion coefficient for Sn2+ of 5.46 x 10(-6) cm(2) s(-1).