The complex atmospheric corrosion of α/δ bronze bells in a marine environment
| Autor: | Mandana Saheb, Chloé Fourdrin, S. Nowak, A. Petitmangin, C. Blanc, Patrick Ausset, Anne Chabas, Ivan Guillot, S.C. Alfaro |
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| Rok vydání: | 2021 |
| Předmět: |
Archeology
Cuprite Materials science Materials Science (miscellaneous) Metallurgy Cassiterite Alloy Conservation engineering.material Chloride Corrosion Chemistry (miscellaneous) visual_art engineering visual_art.visual_art_medium medicine Bronze Ternary operation General Economics Econometrics and Finance Spectroscopy Eutectic system medicine.drug |
| Zdroj: | Journal of Cultural Heritage. 52:153-163 |
| ISSN: | 1296-2074 |
| Popis: | α/δ bronze bells are heritage materials subject to corrosion. The alteration of a high-tin bronze bell casted in the 1930s and exposed to a marine environment in a steeple was studied. The ternary bronze (Cu-Sn-Pb) alloy displays inclusions and a porosity due to micro-shrinkages and poor gas evacuation. This altered bronze is characterized to (1) assess the influence of the manufacturing techniques and (2) hypothesize a micro-infiltration scenario of its alteration. After exposure to the atmosphere, a transformed superficial medium overlaying layers of atacamite-paratacamite-cassiterite appears. Under them, the corrosion of the α dendritic structure and α/δ eutectoid characteristic of bronze bell is evidenced. The α pitting has a pronounced multilayered structure of cassiterite and cuprite-copper chloride, whereas the δ corrosion is composed of cassiterite and traces of cuprite. To understand better the lead impact on corrosion process, samples of the alloy were exposed in the laboratory to a synthetic marine solution. The long-term corrosion behavior of the studied bell shows some similarities to those of other high tin bronze artefacts. The hypothesis of a corrosion scenario emphasizes the importance of the bells manufacturing techniques, α/δ structure of the ternary Cu-Sn-Pb alloy, and infiltrating networks of environmental fluids. |
| Databáze: | OpenAIRE |
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