Significance of Discontinuous Precipitation of Copper in Ancient Silver

Wanhill, R.J.H.

doi:10.1007/s13632-012-0041-9

Cited by 12 publications

(4 citation statements)

References 17 publications

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“…Over more than four decades (1965-2012), there have been several suggestions about the significance of discontinuous precipitation of copper at the grain boundaries of ancient silver [66,67,69,70,[81][82][83]. A review comprising seven case histories (including the Kaptorga, Cauldron, Vase, and Kantharos in the present paper), additional information on discontinuous precipitation, and empirical and theoretical metallurgical considerations [84] was published in 2012 [85]. A summary is given here:…”

Section: The Role(s) Of Discontinuous Precipitation Of Coppermentioning

confidence: 99%

“…Copper precipitation and authenticity: It has been proposed that the precipitate widths and its detailed morphology could be used to date and hence authenticate ancient silver objects [83,84]. The dating possibility is invalid, as demonstrated by metallography of the annealed sample 366 from the Cauldron and the extrapolated Arrhenius-type reaction kinetics of copper precipitation at ambient temperatures [85]. However, in combination with information on provenance and stylistic aspects, the presence of discontinuous precipitation in a silver object may be regarded as additional evidence of antiquity.…”

Section: The Role(s) Of Discontinuous Precipitation Of Coppermentioning

confidence: 99%

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Long-Term Embrittlement of Ancient Copper and Silver Alloys

Oudbashi

Wanhill²

2021

Heritage

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The manifestations of ancient metals’ embrittlement, cracking and fracture, are challenging problems for restorers and conservators, yet the scientific understanding of these problems is limited. In particular, the study and interpretation of fracture surfaces, fractography, is a minor or non-existent consideration for most archaeometallurgical investigations. This paper presents a survey of fractographic analyses, in combination with the more widely used disciplines of microstructural studies, metallography, and chemical analyses for some Old-World copper alloy (bronzes) and high-silver alloy artifacts that have undergone long-term corrosion and embrittlement damage. We show that fractography, as an adjunct to metallography, can improve the interpretation of these types of damage and assist in selecting the best methods for restoration and conservation of the objects made from these alloys.

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Section: The Role(s) Of Discontinuous Precipitation Of Coppermentioning

confidence: 99%

Section: The Role(s) Of Discontinuous Precipitation Of Coppermentioning

confidence: 99%

Long-Term Embrittlement of Ancient Copper and Silver Alloys

Oudbashi

Wanhill²

2021

Heritage

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“…The corrosion process, which results in a brownishblack tarnish, is responsible for the deterioration of silver-copper alloys. The aesthetic value of the artefact is diminished as a result of this tarnish [11]. Increased intergranular cracking, regions of ductile fracture, and brittle intergranular fracture were the results of the item's having corrosion layers, which are related to long-term pollution and oxidation [12,13].…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Set of Coin Silver Spoons of Prince Mohamed Ali

sayed¹

2022

Egypt. J. Chem.

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In this research, a set of four coin silver spoons that belong to prince Mohamed Ali and were struck in Egypt in the name of Sultan Abdul Hamid II (1293-1327 AH / 1876-1909 AD) is investigated. The set was exhibited at Prince Mohamed Ali Museum, in Cairo, Egypt. As it has never been studied before, the study aims to identify the manufacturing technique and the deterioration aspects. Visible imaging and geometrical documentation were undertaken to reveal the preservation condition of the objects. A USB Digital microscope was used to examine the coin spoons. Portable x-ray fluorescence (XRF) was used for the elemental analysis of the alloy, while Scanning Electron Microscopy coupled with energy dispersive X-ray (SEM-EDX) was used in order to identify the corrosion products. Metallographic Microscope was used to identify the alloy microstructure to explore the manufacturing technology. Portable x-ray fluorescence (XRF) showed that the coin spoons are made of coin silver, which is an alloy of silver and copper. While the results of scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX) confirmed the portable x-ray fluorescence analysis that the coin spoons were made of a silver-copper alloy, SEM-EDX analysis also showed the presence of elemental corrosion layers like C, S, and Cl. An investigation with metallography of the crescent-like shape at the end of the hand part of the coin spoon found that the hand area was cast then twisted, It was also revealed that the coin part had been cast first, and then struck afterwards, as seen by the cold-worked dendrites that were deformed.

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“…Hence, numerous studies of ancient silver artefacts exist in the literature, investigating their chemical composition15161718192021, microstructure1517202223, manufacturing processes1524, provenance1617, embrittlement and fracture2223, condition of preservation, corrosion processes and corrosion products142526272829 and their state of conservation2529. These studies normally combine non-destructive testing (NDT) and destructive testing methods, including: metallography, light and scanning electron microscope (SEM) examination including energy-dispersive spectroscopy (EDS) analysis, focused ion beam (FIB) microscopy and micromachining, particle-induced X-ray emission (PIXE) analysis, X-ray fluorescence (XRF) analysis, inductively-coupled plasma (ICP) analysis, X-ray diffraction (XRD), neutron tomography, X-ray photoelectron spectroscopy analysis (XPS), and Raman spectroscopy analysis1516171819202122232526272829303132. Yet, because of the rareness of such ancient artefacts, from the archaeological perspective, the use of NDT methods is always preferred202130.…”

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confidence: 99%

Metallurgical investigation on fourth century BCE silver jewellery of two hoards from Samaria

Ashkenazi

Gitler²,

Stern

et al. 2017

Sci Rep

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A fourth century BCE silver jewellery collection, which is part of two hoards of Samarian coins (the Samaria and Nablus Hoards), was studied by non-destructive analyses. The collection, which consists of pendants, rings, beads and earrings, had been examined by visual testing, multi-focal microscopy and SEM-EDS analysis. In order to enhance our knowledge of past technologies of silver jewellery production, we developed a metallurgical methodology based on the chemical composition of the joints and bulk. The results show that all artefacts are made of silver containing a small percentage of copper. Higher copper concentrations were measured in the joining regions. Our research indicates that the manufacturing of the jewellery from both hoards involved similar techniques, including casting, cutting, hammering, bending, granulating and joining methods, indicating that the artefacts were made by trained silversmiths. Although the burial date of the Samaria Hoard – 352 BCE – is some 21 years earlier than that of the Nablus Hoard – circa 331 BCE, a noted continuity in the local production technology is apparent in the analysed items. This information provides better understanding of the technological abilities in the late Persian-period province of Samaria and bears implications on the local silver coins produced in the region.

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Significance of Discontinuous Precipitation of Copper in Ancient Silver

Cited by 12 publications

References 17 publications

Long-Term Embrittlement of Ancient Copper and Silver Alloys

Long-Term Embrittlement of Ancient Copper and Silver Alloys

Characterization of a Set of Coin Silver Spoons of Prince Mohamed Ali

Metallurgical investigation on fourth century BCE silver jewellery of two hoards from Samaria

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