Analysis on the trouble in acidic copper plating caused by exceeding sulfuric acid

In industrial manufacturing,the exceeding of sulfuric acid in acidic copper plating causes passivation of anode,increase of cell voltage,and decrease of working current.The effect of sulfuric acid content on the solubility of copper sulfate was discussed.The results showed that the solubility of copper sulfate in aqueous solution is decreased rapidly by adding sulfuric acid more than 50 g/L.In electroplating process,the concentration of Cu2+ is increased gradually on anode surface when the content of sulfuric acid is too high.As a result,the anode is passivated and the production is stopped due to the separation of copper sulfate crystals on anode surface.