In situ studies of the initial atmospheric corrosion of copper influence of humidity, sulfur dioxide, ozone, and nitrogen dioxide

Infrared reflection absorption spectroscopy and quartz crystal microbalance , integrated into a one-surface analytical system, and complemented with ta pping mode atomic force microscopy, has been used to explore the metal/atmo sphere interfacial region under atmospheric pressure conditions. This uniqu e combination of ill situ techniques, all possessing submonolayer sensitivi ty, has revealed information on the different accelerating roles of ozone ( O-3) and nitrogen dioxide (NO2) on the SO2-induced atmospheric corrosion of copper. The formation of reaction products could be followed quantitativel y with respect to chemical identity and kinetics. Exposure in SO2-containin g humidified air resulted in CuSO3. xH(2)O-like species, formed atop a cupr ous oxide, designated Cu2O, all over the copper surface. O-3 introduction r esulted in an accelerated mass gain with an increased formation rate of bot h Cu2O and of CuSO4. xH(2)O all over the surface. NO2 introduction resulted in less mass gain than observed under SO2 and O-3, with no formation of ne w Cu2O, an initial oxidation of CuSO3. xH(2)O to CuSO4. xH(2)O, and with su lfite oxidation gradually replaced by copper nitrate formation, possibly as CuNO3(OH)(3) The formation rates of the dominating end products, CuSO4. xH (2)O in SO2/O-3 and Cu2NO3(OH)(3) in SO2/NO2 seemed to be limited by the su pply of the gaseous constituents. (C) 2000 The Electrochemical Society. S00 13-4651(00)01-001-6. All rights reserved.