Phosphate ions used as green inhibitor against copper corrosion in tap water

Abstract

Three dosages of PO3 4 ions are evaluated as corrosion inhibitors of copper in artificial tap water by measuringthe corrosion potential, polarization resistance, electrochemical impedance and reflectance spectra.The water is moderately hard, highly carbonated and chloride-rich. The results show that the surfacefilm is composed by Cu2O. When the inhibiting agent is added, the film becomes thicker, denser and morecompact. This behaviour is attributed to CuO incorporating into the passive layer. The optimal dosage ofinhibitor is 10 mg l1 P when the polarization resistance increases three times. The inhibitor retards thepit initiation, without hindering pit growth.