New Citrate Copper Plating Bath

A new copper plating bath is found which capability is close to cyanide copper plating bath and can be the good substitute of cyanide copper plating bath in actual production. The new bath can plate directly on steel, copper, brass, zincated aluminum and most high quality properly prepared zinc diecastings in both rack and barrel installations. The copper deposit which plates must be fine grained, smooth, dense and ductile. The cyanide copper plating bath is applying very widely in bottom plating. But the cyanide is very poison which is very dangerous in the producing process and the dispose process of waste water and residue. So, to find a non-cyanide alkaline copper plating bath is a great target of the plating operator. Although there are many non-cyanide alkaline copper plating baths, but they can't replace the cyanide alkaline copper plating bath all along because the problem of the poor adhesion between copper deposit and zinc diecastings hasn't been disposed.. Through a period of exploring and researching process, we find a new citrate copper plating bath which contains a main complexant and a appropriate assistant complexant. The bath can reduce the balance potential of copper effectively. When the workpieces are immerged into the bath, the immersion deposit phenomena will not happen. Hence the adhesion between copper deposit and workpiece is very good. The most difficult problem of non-cyanide copper plating is disposed. At the same time, we apply some copper plating addition agents in the bath which ameliorate the capability of the bath and increase the quality of the copper deposit. According to the national standard method, we analyze the influence of most conditions and parameters, and test the capability of the bath and the quality of the copper deposit. The result indicate that the capability of the bath is very good in most aspects. This new citrate copper plating bath can plate directly on steel, copper, brass, zincated aluminum and most high quality properly prepared zinc diecastings in both rack and barrel installations. And the copper deposit is fine grained, smooth, dense, ductile and adhesion good. The bath can replace cyanide copper plating bath entirely. It will has very good foreground in actual producing.