Copper corrosion in industrial waters - A multimethod analysis

The spectral analysis of the electrochemical noise produced by copper corro sion during exposures to artificial industrial waters of different pH value s was compared to the results obtained by electrochemical impedance spectro scopy (EIS), The noise impedance spectra are in good agreement with EIS spe ctra. A particularly good agreement is found at low frequencies. thus allow ing a correct estimation of the low-frequency limit of copper impedance spe ctra. Atomic absorption analysis was also performed to validate the finding s of EIS and electrochemical noise analysis, Different techniques were used to investigate the nature of the surface films grown under different pH co nditions: scanning electron microscope observations, electron probe microan alysis, Fourier transform infrared spectroscopy, and electrochemical reduct ion tests. Cu2O was found to be the main corrosion product under all invest igated conditions, while only traces of copper carbonate or basic copper ca rbonate were detected with the exception of pH 3.0. (C) 1999 The Electroche mical Society. S0013-4651(96)05-059-9. All rights reserved.