Quantitative in situ analysis of initial atmospheric corrosion of copper induced by acetic acid.

The initial atmospheric corrosion of copper was investigated by means of a quantitative in situ analysis in an atmospherecontaining 120 ppb of acetic acid and 95% relative humidity using a quartz crystal microbalance (QCM) integrated with infraredreflection absorption spectroscopy (IRAS). Crystalline cuprous oxide (various structural forms of Cu2O) and hydrated copperacetate were detected as corrosion products during up to 100 h of exposure. The quantification of data was made possible throughan observed linear relationship between the absorbance of vibrations (IRAS)of both phases and the corresponding mass (QCM).The quantification of cuprous oxide was further supported by ex situ coulometric reduction of the corrosion products. The growthrate of cuprous oxide was initially very fast but almost zero after 20 h exposure where it reached an average thickness of13 ± 1 nm. Copper acetate exhibited a more constant growth rate. Atomic force microscopy showed a uniform growth of cuprousoxide with surface roughness that increased with time and localized formation of copper acetate. The quantified data are consistentwith a previously proposed model that involves proton- and acetate-induced dissolution of copper and subsequent precipitation ofcuprous oxide and copper acetate.
Uppdaterad från accepted till published(20101105)QC 20101105