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The corrosion inhibition efficiency of octadecanethiol (ODT) for zinc and a zinc-copper patterned model sample (Zn-Cu) has been explored during exposure in an atmosphere that mimics indoor atmospheric corrosion containing humidified air (80% relative humidity at 20 degrees C) and formic acid (around 100 ppb). The corrosion kinetics were monitored in situ with infrared reflection absorption spectroscopy, and the local nature of corrosion effects post-analyzed with complementary scanning electron microscopy, atomic force microscopy and confocal Raman spectroscopy. ODT shows initially a corrosion inhibiting ability both on zinc and on Zn-Cu. This ability decreases with time due to local removal of ODT, which causes micro-galvanic effects that eventually result in corrosion rates that exceed those for the uncovered samples. On bare and ODT-covered samples, the presence of a copper-zinc junction results in both accelerated corrosion and in structurally more developed corrosion products. Overall, the results suggest that ODT can function as a temporary corrosion inhibitor in representative indoor environments on zinc and zinc with zinc-copper junctions., QC 20140822

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

Atomic force microscopy (AFM) and infrared reflection absorption spectroscopy (IRAS) were used for in situ investigations of the initial atmospheric corrosion of bronze. In addition ex situ XPS investigations were carried out on the samples before and after the exposure, as well as on the sputtered bronze sample. Investigations were carried out in synthetic air with 80% relative humidity (RH) and synthetic air with 80% RH with 250 ppb SO2. At 80% RH, small features covering the surface were observed with AFM, whereas IRAS detected that more water is adsorbed on the bronze sample surface compared to pure copper. Large features on top of smaller features were observed with AFM on the bronze surface exposed to SO2-containing humidified air. These large features were identified as copper sulfite. Furthermore, cuprous oxide was detected approximately 500 min after the introduction Of SO2. This fact and the XPS results indicate the formation of a protective lead oxide layer already during the preparation of the sample, which is destroyed by the SO2-containing environment and leads to the formation of cuprous oxide and copper sulfite., QC 20100525

Three complementary experimental techniques for in situ surface analysis have been combined for the first time in order to explore the chemistry and physics of a copper surface exposed to humidified air. Infrared reflection absorption spectroscopy, quartz crystal microbalance and atomic force microscopy provide a congruent picture of the processes occurring at the surface. At a given relative humidity, cuprous oxide forms according to an approximately logarithmic rate law. In addition, an aqueous adlayer of constant mass physisorbs on the surface. Increased relative humidity stimulates the physisorption of water and enhances the nucleation rate of oxide grains, thereby increasing the formation rate of cuprous oxide., QC 20100525