Electrochemical behaviour of electrodeposited tin in aqueous solutions of pH 1 to 3 and 10 to 13 and the effect of chloride

SummaryElectrodeposited tin from a fluoborate bath and spectrographically pure tin have been polarised in deaerated aqueous solutions of pH 1 to 3 and 10 to 13 in the presence and absence of 0.05M chloride. Polarisation curves for the deposits and the pure tin are generally similar, but the results in pH 1, 2–3, 10 and 12–13 are different. The corrosion resistance of the electrodeposit was superior to that of the pure tin throughout the pH range tested, and the addition of chloride substantially decreased the corrosion resistance of both the tin and the electrodeposit. Some results on electrodeposits from fluoborate, acid sulphate, and stannate baths in the as-received, heat-treated and chromated conditions, tested in a pH 2 solution, are also presented.