The Influence of pH on Electrochemical Behavior of Copper in Presence of Chloride Ions

The electrochemical behavior of copper in borax buffer solutions in pH range 8.0-12.3, with or without chlorides, was investigated. It was found that with increasing pH of the solution the open circuit potential becomes more negative. Analysis of the polarization curves recorded in these experiments leads to a conclusion that anodic polarization behavior of copper includes transition from active to passive region with two anodic current peaks that include formation of Cu2O film and a film that contains Cu(OH)2 and CuO. It was found that there is a linear relationship between E and log(i) in the active dissolution region, with a Tafel slope of 60mV/dec indicating that the dissolution is not activation controlled and is determined by the diffusion of soluble CuCl2-