The role of Sn on the long-term atmospheric corrosion of binary Cu-Sn bronze alloys in architecture

The role of Sn on the atmospheric corrosion performance of binary Cu-Sn bronze alloys (4–6 wt.% Sn) compared with Cu metal used in outdoor architecture is elucidated in terms of microstructure, native surface oxide composition, patina evolution, corrosion rates, appearance and metal release. Results are presented for non-exposed surfaces and surfaces exposed at different urban and marine sites in Europe up to 5 years and based on multi-analytical findings from microscopic, spectroscopic, electrochemical and chemical investigations. Alloying influenced the corrosion, aesthetic appearance and patina evolution, differently for urban and marine sites, whereas no effects were observed on the release pattern.The European Copper Institute, Brussels, Belgium and the Scandinavian Copper Development Association are highly acknowledged for financial support, providing material and giving valuable comments. We are also grateful to Oskar Karlsson and Mats Randelius at Swerea Kimab, Stockholm Sweden for help with SEM/EDS imaging and GDOES analyses. S. Jafarzadeh, J. Brunk and J. Sandberg, former PhD-students at KTH, are highly acknowledged for help with the field exposures. The authors would like to express their sincere gratitude to the China Scholarship Council for supporting Tingru Chang’s stay at KTH Royal Institute of Technology, Sweden.Peer Reviewe