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).