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Boccaccini F, Riccucci C, Messina E, Pascucci M, Bosi F, Aldega L, Ciccola A, Postorino P, Favero G, Ingo GM, Di Carlo G. Early Stages of Metal Corrosion in Coastal Archaeological Sites: Effects of Chemical Composition in Silver and Copper Alloys. MATERIALS (BASEL, SWITZERLAND) 2024; 17:442. [PMID: 38255610 PMCID: PMC10820586 DOI: 10.3390/ma17020442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024]
Abstract
In this study, metal disks with different chemical composition (two Ag-based alloys and three Cu-based alloys) were buried in the soil of coastal archaeological sites for a period of 15 years. The aim was to naturally induce the growth of corrosion patinas to obtain a deeper insight into the role of alloying elements in the formation of the patinas and into the degradation mechanisms occurring in the very early stages of burial. To reach the aim, the morphological, compositional and structural features of the patinas grown over 15 years were extensively characterized by optical microscopy, field emission scanning electron microscopy coupled with energy dispersive spectrometry, X-ray diffraction and micro-Raman spectroscopy. Results showed that the Cu amount in Ag-based alloys strongly affected the final appearance, as well as the composition and structure of the patinas. Corrosion mechanisms typical of archaeological finds, such as the selective dissolution of Cu, Pb and Zn and internal oxidation of Sn, occurred in the Cu-based alloys, even if areas enriched in Zn and Pb compounds were also detected and attributed to an early stage of degradation. In addition, some unusual and rare compounds were detected in the patinas developed on the Cu-based disks.
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Affiliation(s)
- Francesca Boccaccini
- Institute for the Study of Nanostructured Materials (ISMN), National Research Council (CNR), SP35d, 9, 00010 Montelibretti, Italy; (C.R.); (E.M.); (M.P.); (G.M.I.)
- Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy; (F.B.); (L.A.)
| | - Cristina Riccucci
- Institute for the Study of Nanostructured Materials (ISMN), National Research Council (CNR), SP35d, 9, 00010 Montelibretti, Italy; (C.R.); (E.M.); (M.P.); (G.M.I.)
| | - Elena Messina
- Institute for the Study of Nanostructured Materials (ISMN), National Research Council (CNR), SP35d, 9, 00010 Montelibretti, Italy; (C.R.); (E.M.); (M.P.); (G.M.I.)
| | - Marianna Pascucci
- Institute for the Study of Nanostructured Materials (ISMN), National Research Council (CNR), SP35d, 9, 00010 Montelibretti, Italy; (C.R.); (E.M.); (M.P.); (G.M.I.)
| | - Ferdinando Bosi
- Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy; (F.B.); (L.A.)
| | - Luca Aldega
- Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy; (F.B.); (L.A.)
| | - Alessandro Ciccola
- Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy; (A.C.); (G.F.)
| | - Paolo Postorino
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy;
| | - Gabriele Favero
- Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy; (A.C.); (G.F.)
| | - Gabriel Maria Ingo
- Institute for the Study of Nanostructured Materials (ISMN), National Research Council (CNR), SP35d, 9, 00010 Montelibretti, Italy; (C.R.); (E.M.); (M.P.); (G.M.I.)
| | - Gabriella Di Carlo
- Institute for the Study of Nanostructured Materials (ISMN), National Research Council (CNR), SP35d, 9, 00010 Montelibretti, Italy; (C.R.); (E.M.); (M.P.); (G.M.I.)
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