Additives of Pyrophosphate Bath for Electroplating of Cu-Sn Alloy Coating

Electroplating of Cu-Sn alloy coating in pyrophosphate bath is the most important electroplating process which can substitute Cu-Sn cyanide electroplating,but the biggest shortcoming of it is slow deposition rate and poor anti-corrosion properties of Cu-Sn alloy coating.The influence of additives on the properties of Cu-Sn coating was studied by electrochemical and weight-loss methods.The results showed that the optimal additives of pyrophosphate Cu-Sn electroplating are 0.5 g/L ethylenediamine(brightener),0.5 g/L HCHO(auxiliary brightener) and 0.5 g/L SDBS(surfactant).