Combined in-situ investigations of atmospheric corrosion of copper with SFM and IRAS coupled with QCM

Abstract

Scanning force microscopy (SFM) and infrared reflection absorption spectroscopy (IRAS) coupled with quartz crystal microbalance (QCM) were used for in-situ investigations of the atmospheric corrosion of pure copper. Based on chemical and kinetic studies obtained by IRAS/QCM, tapping mode atomic force microscopy (TM-AFM) and phase detection imaging (PDI) were applied to gain information about the topography changes of the sample surface with emphasis on the shape and lateral distribution of the corrosion products. Investigations were carried out in synthetic air with 60 and 80% relative humidity (RH). At 60% RH, small features partly covering the surface could be observed with TM-AFM. These features were identified as cuprous oxide with IRAS. Contrary to these results, a fast formation of a layer of cuprous oxide entirely covering the sample surface was observed at 80% RH with TM-AFM. QCM investigations showed a higher formation rate of cuprous oxide at 80% than at 60% RH but in both cases, a high corrosion rate at the beginning of the exposure, which decreases with progressing time.