Comparison of Electrochemical Corrosion Behavior of Copper in Liquid Film in Atmosphere Containing SO₂ or H₂S

The electrochemical corrosion behavior of copper in liquid film under atmospheric condition containing SO2 or H2S was comparatively analyzed using electrochemical impedance spectroscopy and polarization curves. Results indicate that the addition of SO2 or H2S to the atmosphere decreases the charge transfer resistance and surface film resistance, enlarges the double-layer capacitance and surface film capacitance of copper electrode. The corrosion potential of copper shifts negatively and corrosion current density increases with the increase of concentration of SO2 or H2S. The existence of H2S or SO2 in the atmosphere may change the composition of corrosion products on copper electrode surface, reduce the electrode reaction resistance, promote the anodic dissolution and accelerate the corrosion of copper. H2S exhibits greater corrosion to copper among the two kinds of air pollutants at the same concentration.