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Medientyp: E-Artikel Titel: Characterization of the patina formed on a low tin bronze exposed to aqueous hydrogen sulfide Beteiligte: Chan, Michelle; Capek, Alexandra; Brill, Daniel A.; Garrett, Simon J. Erschienen: Wiley, 2014 Erschienen in: Surface and Interface Analysis, 46 (2014) 7, Seite 433-441 Sprache: Englisch DOI: 10.1002/sia.5520 ISSN: 0142-2421; 1096-9918 Entstehung: Anmerkungen: Beschreibung: The dark gray corrosion layer (patina) formed on the surface of a polished low tin bronze alloy following exposure to a deoxygenated and saturated aqueous solutions of H2S has been characterized by X‐ray photoelectron spectroscopy, scanning electron microscopy‐energy dispersive spectroscopy and X‐ray diffraction. The system represents a model for bronze corrosion in reducing conditions where sulfate‐reducing bacteria in soils or deoxygenated seawater may generate H2S during respiration. The initial surface was dominated by metallic copper together with Sn, Pb and Zn oxides and hydroxides. Surface enrichment of Pb and Zn was noted because of a smearing effect during polishing. At least some of the lead was crystalline. In contrast, the corrosion layer formed by H2S(aq) exposure was dominated by polycrystalline Cu2S (low and high chalcocite) and smaller concentrations of CuSO4 · nH2O. This surface was enriched with Zn as Zn(OH)2. Lead was present as redeposited PbS (galena) crystallites in at least two different morphologies. Unlike bronzes exposed to oxidizing conditions, which develop protective SnO2 layers, the H2S(aq)‐exposed surface was considerably depleted in Sn. Copyright © 2014 John Wiley & Sons, Ltd.