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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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Doménech‐Carbó A, Mödlinger M, Osete‐Cortina L, Doménech‐Carbó MT. Electrochemical Approximation to Bronze Age Chronology via Multiple Scan Voltammetry. ChemElectroChem 2023; 10:e202300405. [PMID: 38529335 PMCID: PMC10962692 DOI: 10.1002/celc.202300405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/15/2023] [Indexed: 03/27/2024]
Abstract
Insert A multiple-scan voltammetry strategy is described and applied to a set of 107 Bronze Age and later copper/bronze objects, mainly from sites in Central Europe. This methodology allows the study of the compositional and textural properties (compactness, crystallinity, degree of hydration) of the patina to be studied from the accumulated peak current values for the characteristic signals corresponding to the reduction of cuprite and tenorite to metallic copper. A new model for the relationship between peak current and the depth reached in successive scans is presented and used to discriminate samples of different provenance and manufacturing technique, as well as their ascription to different Bronze Age periods.
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Affiliation(s)
- Antonio Doménech‐Carbó
- Department of analytical chemistryUniversitat de ValènciaDr. Moliner, 5046100BurjassotValènciaSpain
| | - Marianne Mödlinger
- Institut für ArchäologienUniversität InnsbruckLanger Weg 116020InnsbruckAustria
| | - Laura Osete‐Cortina
- Institut für ArchäologienUniversität InnsbruckLanger Weg 116020InnsbruckAustria
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Cohen M, Ashkenazi D, Gitler H, Tal O. Archaeometallurgical Analysis of the Provincial Silver Coinage of Judah: More on the Chaîne Opératoire of the Minting Process. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2200. [PMID: 36984080 PMCID: PMC10052650 DOI: 10.3390/ma16062200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Silver coins were the first coins to be manufactured by mass production in the southern Levant. An assemblage of tiny provincial silver coins of the local (Judahite standard) and (Attic) obol-based denominations from the Persian and Hellenistic period Yehud and dated to the second half of the fourth century BCE were analyzed to determine their material composition. Of the 50 silver coins, 32 are defined as Type 5 (Athena/Owl) of the Persian period Yehud series (ca. 350-333 BCE); 9 are Type 16 (Persian king wearing a jagged crown/Falcon in flight) (ca. 350-333); 3 are Type 24 series (Portrait/Falcon) of the Macedonian period (ca. 333-306 BCE); and 6 are Type 31 (Portrait/Falcon) (ca. 306-302/1 BCE). The coins underwent visual testing, multi-focal light microscope observation, XRF analysis, and SEM-EDS analysis. The metallurgical findings revealed that all the coins from the Type 5, 16, 24, and 31 series are made of high-purity silver with a small percentage of copper. Based on these results, it is suggested that each series was manufactured using a controlled composition of silver-copper alloy. The findings present novel information about the material culture of the southern Levant during the Late Persian period and Macedonian period, as expressed through the production and use of these silver coins.
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Affiliation(s)
- Maayan Cohen
- Department of Archaeology and Ancient Near Eastern Cultures, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
- Leon Recanati Institute for Maritime Studies, University of Haifa, Haifa 3498838, Israel
| | - Dana Ashkenazi
- School of Mechanical Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Haim Gitler
- Israel Museum, Derech Rupin 11, Jerusalem 9171002, Israel
| | - Oren Tal
- Department of Archaeology and Ancient Near Eastern Cultures, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
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Doménech-Carbó A, Scholz F, Brauns M, Tiley-Nel S, van Bennekom J, van Bork E, Barrio J, Martínez-Caballero S, Oliver A, Aguilella G, Martínez B, Doménech-Carbó MT. Electrochemical dating of archaeological gold based on repetitive voltammetry monitoring of silver/copper in depth concentration gradients. Microchem J 2023. [DOI: 10.1016/j.microc.2023.108661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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A Multi-Analytical Approach on Silver-Copper Coins of the Roman Empire to Elucidate the Economy of the 3rd Century A.D. Molecules 2022; 27:molecules27206903. [PMID: 36296493 PMCID: PMC9607305 DOI: 10.3390/molecules27206903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 10/09/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
In this study, 160 silver-copper alloy denarii and antoniniani from the 3rd century A.D. were studied to obtain their overall chemical composition. The approach used for their characterisation is based on a combination of physical, chemical, and chemometric techniques. The aim is to identify and quantify major and trace elements in Roman silver-copper coins in order to assess changes in composition and to confirm the devaluation of the currency. After a first cataloguing step, μ-EDXRF and SEM-EDX techniques were performed to identify the elements on the coins’ surface. A micro-destructive sampling method was employed on a representative sample of the coins to quantify the elements present in the bulk. The powder obtained from drilling 12 coins (keeping the two categories of coins separate) was dissolved in an acidic medium; heated and sonicated to facilitate dissolution; and then analysed by ICP-AES and ICP-MS. The two currencies had different average alloy percentages; in particular, the % difference of Ag was about 8%. The other elements were found in concentrations <1 wt%. Of these, the element highest in concentration were Pb and Sn, which is in agreement with the literature. The multivariate analysis performed on the data acquired revealed two groups of coins, corresponding to the two currencies.
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Micro and Nanoscale Structures and Corrosion Patterns in Brass: The Case Study of Ancient Roman Orichalcum Coins. MINERALS 2022. [DOI: 10.3390/min12070827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This study investigated the micro and nanoscale structure in Cu-Zn alloy, as well as its corrosion patterns. To achieve this goal, a set of Roman orichalcum coins were analysed using Scanning Electron Microscopy (SEM-EDS), X-ray maps, high resolution field emission scanning electron microscopy (HR-FESEM-EDS) and electron microprobe analyser (EMPA) techniques. The samples showed a high degree of corrosion on their external surfaces, which evolved in depth up to ~1 mm. Micro and sub-micro imaging of the inner metal highlighted the presence of “stressed areas” caused by mechanical processing work, representing the trigger zone of corrosion and causing the loss of material. These images also permitted us to follow the grain-grain interface and selective Zn-dealloying in the examined samples. X-ray maps of Cu and Zn helped us to understand the evolution of the dezincification process, from rim to core. HR-FESEM-EDS imaging investigation highlighted a heterogeneous composition within the strain line structures, confirming that the mechanically stressed areas were active zones for corrosion processes. Cracks and voids also characterised the patina. Conversely, the uncorroded cores of the samples were not affected by dealloying.
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Abstract
In the last decades, the interest in the development of protective coatings for movable and immovable Cultural Heritage (CH) assets has decidedly increased. This has been mainly prompted by the raising consciousness on preservation requirements for cultural artefacts and monuments, which has consequently determined the development of new protective products. From acrylic resins used at the end of the last century to the up-to-date biomaterials and nanoparticles employed nowadays, the research has made a giant step forward. This article reviews the progresses, the technical challenges, and the most recent advances in protective coatings for archaeological metal, glass, and stone artefacts. It aims at offering a comprehensive and critical overview of the progressions in conservation science and displaying how research has optimized polymers in order to solve deterioration problems. Attention is given to recently developed materials, hybrid coatings, and corrosion inhibitors. This work seeks to provide a reference point for future research and to offer a wide-ranging introduction on the newly available material technologies to restorers and conservators.
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Microstructure and chemical composition of Roman orichalcum coins emitted after the monetary reform of Augustus (23 B.C.). Sci Rep 2019; 9:12668. [PMID: 31481740 PMCID: PMC6722059 DOI: 10.1038/s41598-019-48941-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/07/2019] [Indexed: 11/28/2022] Open
Abstract
A collection of ancient Roman orichalcum coins, i.e., a copper-zinc alloy, minted under the reigns from Caesar to Domitianus, have been characterised using scanning electron microscopy (SEM-EDS) and electron microprobe analysis (EMPA). We studied, for the first time, coins emitted by Romans after the reforms of Augustus (23 B.C.) and Nero (63–64 A.D). These coins, consisting of asses, sestertii, dupondii and semisses, were analysed using non- and invasive analyses, aiming to explore microstructure, corrosive process and to acquire quantitative chemical analysis. The results revealed that the coins are characterized by porous external layers, which are affected by dezincification and decuprification processes. As pictured by the X-ray maps, the elemental distribution of Cu and Zn shows patterns of depletion that in some cases penetrate in deep up to 1 mm. The composition of the un-corroded nucleus is a Cu-Zn alloy containing up to 30% of Zn, typical of coins produced via cementation process.
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Doménech-Carbó MT, Álvarez-Romero C, Doménech-Carbó A, Osete-Cortina L, Martínez-Bazán ML. Microchemical surface analysis of historic copper-based coins by the combined use of FIB-FESEM-EDX, OM, FTIR spectroscopy and solid-state electrochemical techniques. Microchem J 2019. [DOI: 10.1016/j.microc.2019.05.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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