Solid-state electrochemical characterization of emissions and authorities producing Roman brass coins

Fazio, Melania Di; Felici, Anna Candida; Catalli, Fiorenzo; Doménech‐Carbó, María Teresa; Vito, Caterina De; Doménech‐Carbó, Antonio

doi:10.1016/j.microc.2019.104306

Cited by 16 publications

(17 citation statements)

References 54 publications

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“…Indeed, the first 3μm of the patina showed microdomains with low amount of Zn, due to a selective dealloying. The Cu and Zn segregation areas are well visible in the deeper region of the analysed patina (Di Fazio et al, 2020). The patterns described with FIB-FESEM are comparable to those previously observed (Di Fazio et al, 2019).…”

Section: Accepted Manuscriptsupporting

confidence: 87%

“…Stereomicroscope examination does not show erosion features denoting sandblasting, nor smoothing associated to intense chemical cleaning. All the historical and numismatic information about the samples are reported elsewhere (Di Fazio et al, 2019, 2020.…”

Section: Methodsmentioning

confidence: 99%

“…Oxalates are the result of the degradation of lipids and subsequent complexation with metal ions over a long period of time: this indicates that the coin's original surface is preserved. In some spectra a band at ~1738 cm -1 , assigned to the C=O group (Di Fazio et al, 2020), may be detected as well. It can indicate the presence of lipids, which can again be ascribed to the contact of the coins with the hand skin oils of their ancient users (Doménech-Carbó M. T.…”

Section: Atr-ftir Information From the Patinamentioning

confidence: 98%

“…The reduction of tenorite (CuO) occurs between -0.4 and -0.5 Volt (Doménech-Carbó A. et al, 2017. In turn, the reduction of zinc corrosion products will occur at more negative potentials, being indistinguishable from the hydrogen evolution reaction (HER) process under the experimental conditions (Di Fazio et al, 2020). In the positive-going potential scan voltammograms, anodic signals between 0.0 and +0.20 Volt and at -0.80 Volt (A2) can in principle be attributed to the oxidative dissolution (anodic stripping) of the metal redeposition, as a result of the reduction of corrosion products formed at negative potentials.…”

Section: Voltammetric Pattern and Groupingmentioning

confidence: 99%

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Multi-analytical approach for an archaeometric study on orichalcum coins

Fazio¹

2022

ROL

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Orichalcum is a Cu-Zn based alloy known since the 1 st millennium BC. The cementation was the ancient technique used for its production. The PhD project here presented aimed to characterise this alloy and to evaluate its degradation: for this purpose, non-destructive, nano-invasive and destructive techniques were used on a collection of ancient coins issued from the 1 st century BC to the end of the 1 st century AD. In particular, a multi-analytical approach was used: to investigate the patinas and their corrosive patterns, to study the alloy microstructures and their degradation, to describe the dezincification process and grouping the coins by emission. In addition, quantitative analyses allowed a complete characterization of this ancient alloy. The multi-analytical approach allowed to review the previous theories used for dating samples in orichalcum. This project wanted to contribute to the current knowledge on Roman coinage and to attempt to investigate the mechanisms of corrosive processes affecting ancient alloys.

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Section: Accepted Manuscriptsupporting

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Atr-ftir Information From the Patinamentioning

confidence: 98%

Section: Voltammetric Pattern and Groupingmentioning

confidence: 99%

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Multi-analytical approach for an archaeometric study on orichalcum coins

Fazio¹

2022

ROL

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“…Brass has been used since the Roman period for various applications, including coins, musical instruments, 'golden' helmets, jewellery and ornaments [27][28][29]. It has a beautiful golden-yellow appearance and advanced properties, such as hardness (it is stronger and harder than copper and can be hardened further by cold working), and excellent corrosion resistance in salt water environments.…”

Section: Technological Developments Of Brass Alloy Fasteningsmentioning

confidence: 99%

The Nineteenth-Century Molyneux’s Boat: Archaeometallurgical Perspective of its Metal Fastenings

Bram

Iddan

Ashkenazi

et al. 2020

Metallogr. Microstruct. Anal.

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The 4.4-m-long vessel designated as Molyneux's boat was built in England in 1836. During its conservation in 2008, metal fastenings were retrieved, and 12 of them were examined by XRF, metallographic and multifocal light microscopy, microindentation hardness measurement and SEM-EDS analysis. The results show the use of manufacturing techniques developed at different times: the copper fastenings were made by traditional methods-intensive hammering to their final shape followed by annealing; the screws and nuts were made of brass containing ~ 36 wt% Zn and were probably a post-1848 product; and the bolt was made of low-carbon steel (produced by the Bessemer process) and shaped by plastic deformation, perhaps through a thread-rolling process. The bolt was galvanized, thus most probably manufactured after 1856. It appears that the boat was originally built using copper fastenings, and some of which were replaced by galvanized bolts and brass screws during minor refitting.

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Mott–Schottky Analysis of Historical and Archaeological Copper–based Objects

Doménech‐Carbó,

Mödlinger,

Osete‐Cortina

et al. 2024

ChemElectroChem

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The application of Mott–Schottky (M−S) analysis of impedance data to sub–micro samples extracted from the corrosion patina of copper, bronze, and brass archaeological artifacts attached to graphite electrodes is described. The corresponding theoretical approach is developed to account for the contribution of the composition and structure of the corrosion patina and the effect of the bare graphite substrate. Experimental data in contact with 0.10 M Na2SO4 aqueous solution at pH 6.28 are consistent with the p‐type semiconducting nature of the main copper corrosion products, cuprite, and tenorite. The values of the apparent flat band potential and the slope of the M−S plots allow archaeological samples to be grouped according to their M−S parameters (slopes and intercepts). Assuming equivalent conditions of corrosion, the resulting grouping is judged to be dependent on the composition, and/or method of manufacture, and/or age. Studied samples include Renaissance statues from the Hofkirche in Innsbruck and a variety of objects from museums and Archaeological Heritage Office (soprintendenza) in Austria (Bad Aussee, Johanneum Graz, and the Tyrolean State Museums), and Italy (Genoa and San Remo), dating from the Bronze Age to the 18th century. Complementary data are provided by voltammetry of immobilized particles.

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Solid-state electrochemical characterization of emissions and authorities producing Roman brass coins

Cited by 16 publications

References 54 publications

Multi-analytical approach for an archaeometric study on orichalcum coins

Multi-analytical approach for an archaeometric study on orichalcum coins

The Nineteenth-Century Molyneux’s Boat: Archaeometallurgical Perspective of its Metal Fastenings

Mott–Schottky Analysis of Historical and Archaeological Copper–based Objects

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