Photoelectrochemical Study of the Corrosion and Inhibition on Copper

The corrosion behaviors of Cu in borax buffer solution with different concentrations of NaCl and the inhibition of poly-aspartic(PASP)were studied by photoelectrochemical method.The Cu electrode in the borax buffer solution shows p-type photoresponse which came from Cu_2O layer on its surface.When a little amount of NaCl(0.5 g/L)was added,the Cu_2O layer didn't change its semiconductor style.When more NaCl(0.5—15 g/L)was added,a part of the Cu_2O layer was changed into n-type because of doping Cl~-.When a large amount of NaCl(15 g/L)was added, the Cu_2O layer was totally changed into n-type.When PASP was added and the concentration of NaCl was 2 g/L,PASP played a competitive adsorption with Cl~- and prevented Cu_2O layer from being doped,so the Cu_2O layer showed p-type.When the concentration of NaCl was 30 g/L,the competitive adsorption of PASP only prevented Cu_2O layer from doping slightly,the Cu_2O layer was still changed into n-type,but the n-type was weakened.The Mott-Schottky test results on Cu_2O layer agree well with photoelectrochemistry test ones.