Corrosion products and microstructure of copper alloy coins from the Byzantine-period Ma'agan Mikhael B shipwreck, Israel

Inberg, Alexandra; Ashkenazi, D.; Cohen, M.; Iddan, N.; Cvikel, Deborah

doi:10.1016/j.microc.2018.08.033

Cited by 29 publications

(37 citation statements)

References 39 publications

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“…Surface loss of copper can be easily explained considering the formation of alteration compounds (copper is on the short list of noble metals by many chemists, although its resistance to oxidation is limited with respect to Ag and Au of the same group 11), due to the interaction of the metal material with natural oxidizing environmental agents (mainly forming oxides, hydroxides, sulphurs, sulphates, carbonates and chlorides). These interactions are also well described by Inberg et al [19].…”

Section: Icp-aes Quantitative Results and Discussionsupporting

confidence: 71%

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Elemental characterization of surface and bulk of copper-based coins from the Byzantine-period by means of spectroscopic techniques

Crosera

Baracchini

Prenesti

et al. 2019

Microchemical Journal

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Thirty-three Byzantine copper-based coins (so-called anonymous follis) from 970 to 1085 A.D. were investigated in order to determine the elemental composition both of the bulk and of the surface. The ancient coins analysed − belonging to the Thomas Bertelè Collection, now located in the Bottacin Museum of Padova (Italy) − were studied by way of physical, chemical and chemometric testing techniques. This study aims to obtain information on socio-economic aspects of the Byzantine Empire using chemical and physical data of currency as indirect indicators. First, the weight, diameter and thickness of each piece were measured, then a micro-Energy Dispersive X-Ray Fluorescence (µ-EDXRF) technique was applied on a cleaned and polished area of the surface of the coin to evaluate the presence of minor elements in a non-destructive fashion. A micro-destructive sampling method for both surface and bulk samples, based on mechanically drilling the edge, was finally employed, and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) was used for the quantitative 2 determination of Cu (the major alloying element), Pb, As, Fe, Zn, Ag, Ni, Sn and Mn (minor elements) in the powder which resulted from drilling each coin, previously dissolved via aqua regia dissolution technique overnight at room temperature.The average copper concentration of the folles was 95.9±3.1% for the bulk and 91.7±3.5% for the surface. The Pb-Cu ratio appears to be an index which can be used to discriminate between different coins, in particular for Class B (from 1030 to 1042 A.D.), as confirmed by exploratory chemometric data analysis. According to our results, all the anonymous Byzantine folles under examination were minted in much the same way and using the same mineral raw materials. Using the chemical data measured on the bulk, we can grasp that the monetary choice of the period under study excluded silver, gold and bronze (concentrations of Pb is low, while Sn resulted undetectable or unquantifiable) to turn, substantially, to a copper-only coinage (deducted the impurities given by the gangue of the starting minerals). Moreover, along the observed period of 120 years, the mass of the coins was significantly reduced (with an overall loss of material of approximately 60%).

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Section: Icp-aes Quantitative Results and Discussionsupporting

confidence: 71%

“…Recent literature on archaeological coins is rich in papers dealing with silver and silver/copper alloy in historical coinage process [12][13][14][15][16][17][18][19].…”

Section: Chemical Analysismentioning

confidence: 99%

Elemental characterization of surface and bulk of copper-based coins from the Byzantine-period by means of spectroscopic techniques

Crosera

Baracchini

Prenesti

et al. 2019

Microchemical Journal

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“…Besides this variety of archaeometrical studies, scientific examinations of historic and archaeological artifacts are normally carried out to recognise the corrosion processes that affect coins to determine the composition and morphology of corrosion layers or patinas, and to thus enable to establish the most suitable conservation treatment. Analytical studies of corrosion patinas on copper-based coins and other artifacts are based on a wide variety of instrumental techniques, including Atomic Absorption Spectroscopy (AAS), X-ray Fluorescence and Microfluorescence (XRF, µ-XRF), Inductively Coupled Plasma-Atomic Emission or Mass Spectroscopy (ICP-AES, ICP-MS), Laser Ablation ICP-MS (LA-ICP-MS), Proton Induced X-ray Emission (PIXE, µ-PIXE), micro-X-ray Diffraction (µ-XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy-X-ray Microanalysis (SEM-EDX), Optical Microscopy (OM), µ-Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Laser Induced Breakdown Spectroscopy (LIBS), Deep Protons Activation Analysis (DPAA), Gamma ray Transmission (GRT) or Neutron Diffraction Analysis, among others [8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Microchemical surface analysis of historic copper-based coins by the combined use of FIB-FESEM-EDX, OM, FTIR spectroscopy and solid-state electrochemical techniques

Doménech‐Carbó

Romero

Doménech‐Carbó

et al. 2019

Microchemical Journal

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A multi-technique strategy, including microscopy, spectroscopic and electrochemical techniques, is proposed to study thin corrosion layers that form on the surface of historic copper-based coins. An accurate characterisation of this external corrosion layer is important for selecting a suitable conservation and/or restoration treatment. For this purpose, a series of copper-based coins from different historical periods and provenances, which mainly exhibited atmospheric corrosion, was analysed. The morphology of the corrosion layer and the upper core of coins was studied in trenches done on coin surfaces with a focused ion beam gun, coupled to a field emission scanning electron microscope-X-ray microanalysis (FIB-FESEM-EDX). The X-ray microanalysis performed with FESEM-EDX on trenches allowed elemental composition profiles on the corrosion layer to be obtained. These results were complemented with the compositional data of the corrosion products provided by the voltammetry of immobilised microparticles (VIMP) and Fourier transform infrared spectroscopy (FTIR), and by studying visual appearance by optical microscopy and colorimetry. Cuprite and tenorite (the latter increased with coin age) were the main identified corrosion products, which were accompanied, to a lesser extent, by copper trihydroxychloride polymorphs. Interestingly, metal oxalates and metalcarboxylate complexes were identified on the corrosion layer of most coins. These unusual alteration products of copper-based coins were formed from the organic matter deposited on coin surfaces given their use when placed in circulation or by further manipulations of collectors.

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“…2009; Inberg et al . 2018). Only this patina is reacted with other ions found in the vicinity of the analysed samples.…”

Section: Resultsmentioning

confidence: 99%

Chemical composition of small fragments of metals from Castillo de Huarmey (Peru): Chemical analysis in the micro‐area using FE‐SEM‐EDS, FE‐EMPA and XRD

et al. 2020

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Small metal fragments were found in the tomb of the Wari culture elite (Castillo de Huarmey, Peru). These objects were subjected to chemical analysis using a scanning electron microscope with energy‐dispersive X‐ray spectroscopy and field emission (FE‐SEM‐EDS), an electron microprobe analyser with field emission (FE‐EMPA) and X‐ray diffraction (XRD) analysis. Chemical composition analysis showed that four different alloys were used to make copper objects. Two different alloys were found in silver alloys. A comparative analysis was made of the artefacts of other cultures from the Middle Horizon Period. They differ in their chemical composition.

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Corrosion products and microstructure of copper alloy coins from the Byzantine-period Ma'agan Mikhael B shipwreck, Israel

Cited by 29 publications

References 39 publications

Elemental characterization of surface and bulk of copper-based coins from the Byzantine-period by means of spectroscopic techniques

Elemental characterization of surface and bulk of copper-based coins from the Byzantine-period by means of spectroscopic techniques

Microchemical surface analysis of historic copper-based coins by the combined use of FIB-FESEM-EDX, OM, FTIR spectroscopy and solid-state electrochemical techniques

Chemical composition of small fragments of metals from Castillo de Huarmey (Peru): Chemical analysis in the micro‐area using FE‐SEM‐EDS, FE‐EMPA and XRD

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