Crossing VIMP and EIS for studying heterogeneous sets of copper/bronze coins

Turo, Francesca Di; Parra, Rafael; Piquero‐Cilla, Joan; Favero, Gabriele; Doménech‐Carbó, Antonio

doi:10.1007/s10008-018-04182-5

Cited by 13 publications

(7 citation statements)

References 55 publications

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“…The above hypothesis is also consistent with several features already described: i) that the position and shape of voltammetric signals in VIMP experiments depends not only on the composition, but also on the shape and size of the microparticles; [18] ii) detailed Raman spectroscopy data showing peaks characterizing crystalline cuprite (114 and 220 cm ‐1 ), amorphous or finely divided (defective) cuprite (420, 525, 625 cm −1 ), crystalline tenorite (297 cm −1 ) and possibly less crystalline tenorite (346 and 631 cm −1 ) in copper‐based patinas; [40] iii) the dependence of electrochemical impedance spectroscopy parameters, directly related to textural properties (compactness, porosity, roughness) of metal patinas, [41] on sampling; iv) the agreement in the grouping of archaeological metal samples using VIMP and EIS [37,41] and VIMP and Raman spectroscopy [37,42] . In addition, it should be noted that the intersection of the SEM/EDX and VIMP data indicates that, under our experimental conditions, the voltammetric experiments are limited to the depth of the patina region in Figure 4.…”

Section: Resultssupporting

confidence: 90%

Electrochemical Approximation to Bronze Age Chronology via Multiple Scan Voltammetry

Doménech‐Carbó,

Mödlinger,

Osete‐Cortina

et al. 2023

ChemElectroChem

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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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Section: Resultssupporting

confidence: 90%

Electrochemical Approximation to Bronze Age Chronology via Multiple Scan Voltammetry

Doménech‐Carbó,

Mödlinger,

Osete‐Cortina

et al. 2023

ChemElectroChem

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“…A multi-analytical approach 29,30 based on µ-Raman 31 , X-ray Diffraction, X-ray Photoelectron Spectroscopy 32 or micro-PIXE 33 was applied to investigate the external layers of metal object. Electrochemical analysis as Voltammetry of Immobilized Micro Particle and Electrochemical Impedance Spectroscopy 34–39 are also used to explore the state of conservation of the patina and to identify the corrosion products.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and chemical composition of Roman orichalcum coins emitted after the monetary reform of Augustus (23 B.C.)

Fazio

Felici

Catalli³

et al. 2019

Sci Rep

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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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“…In the current research, we used Raman spectroscopy to study the corrosion products of the copper-lead coins retrieved from the MMB shipwreck, and we gradually removed the concretion and oxide layers in search of a deeper understanding of the corrosive processes. It is known that such concretion covers protect the coins and impede corrosion [5,18,27]. However, when the alloy on the surface dissolves in submerged settings, metal ions are likely to migrate through cracks to the aquatic environment.…”

Section: Discussionmentioning

confidence: 99%

“…In order to document the cleaning procedure's effect and trace the particularities of the corrosive processes that altered the MMB coins, different analytical methods and measurements were applied. Given the coins' fragility, these methods were required to be sensitive and non-destructive, as is anyway preferable with archaeological objects [26,27]. Our analytical procedure consisted of the following:…”

Section: Methodsmentioning

confidence: 99%

What You Clean Is What You Get: A Novel Chemical Cleaning Technique and the Interpretation of Corrosion Products Found in Late Roman Copper Alloy Coins Retrieved from the Sea

et al. 2022

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Thirteen Late Roman copper alloy coins with a dark concretion layer from the Early Islamic period Ma‘agan Mikhael B shipwreck were chosen to undergo an experimental chemical cleaning and polishing procedure for removing the concretion while limiting the damage to the surviving metal. These coins, and two more without concretion discovered on the beach nearby, were then subjected to a series of non-destructive analyses–visual testing, XRF, multi-focal light microscopy, and Raman spectroscopy–to determine their state of preservation, identify their corrosion products, and acquire information regarding their core material. An additional coin was examined by destructive metallographic light microscopy and SEM-EDS analyses to gain further information concerning the concretion cover. Preservation varied: For some chemically cleaned coins, a shiny orange-coloured metallic surface was exposed, while others were poorly preserved. Moreover, evidence of the stamping process was also observed. The results show that the suggested chemical cleaning treatment could be useful for processing other copper alloy objects retrieved from underwater environments; we propose a 12-step methodology to this effect.

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Crossing VIMP and EIS for studying heterogeneous sets of copper/bronze coins

Cited by 13 publications

References 55 publications

Electrochemical Approximation to Bronze Age Chronology via Multiple Scan Voltammetry

Electrochemical Approximation to Bronze Age Chronology via Multiple Scan Voltammetry

Microstructure and chemical composition of Roman orichalcum coins emitted after the monetary reform of Augustus (23 B.C.)

What You Clean Is What You Get: A Novel Chemical Cleaning Technique and the Interpretation of Corrosion Products Found in Late Roman Copper Alloy Coins Retrieved from the Sea

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