Electrodeposition of CuSn Alloy from Sulfosuccinate Bath

Electrodeposited White bronze (speculum : Cu-Sn 40mass%) shows promise as an alternative to nickel coating. Copper-tin(40mass%) alloy film was deposited over a current density range from 0.5 to 4A/dm2 and at a temperature of 25ºC in the following bath composition : 0.1474mol/L CuSO4, 0.0526mol/L SnSO4, 1.0mol/L sulfosuccinic acid, 0.4mol/L L-methionine and 3g/L polyoxyethylene-α-naphthol. The coexistence of L-methionine and polyoxyethylene-α-naphthol markedly inhibited the deposition of copper over a noble potential range, and markedly reduced subreaction.The copper-tin(40mass%) alloy film obtained was silvery white. Copper and tin ions in the effluent were separated as hydroxide, and the residual concentration of tin and copper ions in the bath shown above decreased to less than 5mg/L.