Metal artifacts

B. E. Brown and co-workers, eds.. Corrosion and Metal Artifacts, NBS Special PubHcation 479, National Bureau of Standards, Washington, D.C., 1977. 

Of all the ancient metallic artifacts that have been left from antiquity, coins are among the most numerous. Since ancient times coins have generally been made from coinage metals or, mostly, from coining alloys, whose chemical and physical properties and economic qualities make them suitable to be used for this purpose. Until the twentieth century, gold, silver, copper, and their alloys were practically the only metals from which coinage was made. All these metals and alloys have the following properties ... 

Gegklini, A. E., N. Bozkurt, and S. Basaran (1988), Metallographic studies of archaeological metal artifacts, Aksay Unites Bilimsel Topilanti Bildinireli Middle East Univ., Ankara, Vol. 1, pp. 229-246. 

Edwards, R. (1996). The effects of changes in groundwater geochemistry on the survival of buried metal artifacts. In Preserving Archaeological Remains In-Situ, eds. Corfield, M., Hinton, P., Nixon, T., and Pollard, A. M., London, Museum of London Archaeology Service, pp. 86-92. 

Linke, R. and Schreiner, M. (2000). Energy dispersive X-ray fluorescence analysis and X-ray microanalysis of medieval silver coins - an analytical approach for non-destructive investigation of corroded metallic artifacts. Mikrochimica Acta 133 165-170. 

Mechanisms regulating deterioration processes in the burial state are still rather unknown and little research has been done on the consequences of long-term corrosion on the stability of the objects. Nevertheless, some studies have been performed on metal artifacts, seeking to characterize the surface layer as well as establish a relationship between the composition of the corrosion products and the environment where they formed. 

The third category of metallic artifacts includes collections of a most different provenance—such as scientific instruments, fine arts, historic pieces, ethnographic specimens, etc., which are usually kept in museums. Contrary to the belief that an object is safe once it enters a museum, certain storage or display conditions may lead to corrosive reactions that are different from those found in the natural environment [264, 265]. Some of these dangers come from off-gassing from materials used to build display cases and rooms, as well as air pollution introduced by visitors. 

Electrochemistry has been used for more than a century in the treatment of ancient metal artifacts [281], Ideally, this technique should be able to reverse the corrosion processes that have progressively transformed the metal into an ionic compound. Depending on the conservation state of the artifact, priorities have to be attributed and the treatment will be different if consolidation, stabilization, or cleaning is privileged. 

MacLeod ID (1991) Identification of corrosion products on non-ferrous metal artifacts recovered from shipwrecks. Stud Conserv 36 222-234. 

Dent Wed P (1977) A review of the history and practice of patination, NBSSP 479. Proceedings of a Seminar, Corrosion and Metal Artifacts - A Dialogue Between Conservators and Archaeologists and Corrosion Scientists held at the National Bureau of Standards, Gaithersburg, Maryland, March 17 and 18, 1976, 77-92. 

Costa V, Dubus M (2007) Impact of the environmental conditions on the conservation of metal artifacts an evaluation using electrochemical techniques, Museum Microclimates,Padfield T (Ed), The National Museum of Denmark 63-65. 

The book has been structured into roughly three parts. First (Chap. 1), an overview of analytical methods applied in the study of cultural goods is presented to situate electrochemical methods in their analytical context. The second part contains voltammetric methods devoted to the identification (Chap. 2), speciation (Chap. 3), and quantitation (Chap. 4) of microsample components from works of art and/or cultural and archaeological pieces. The third part of the book presents selected examples of the deterioration of metal artifacts, outlining aspects peculiar to the cultural heritage conservation field (Chap. 5), and describes hisforic and current issues regarding electrochemical techniques used in restoration treatments and preventive conservation (Chap. 6). 

Curse tablets have some attributes favorable for this kind of lead isotope study. The curse tablets are essentially pure lead metal artifacts. Additionally, the... 

After stent PTA, metallic artifacts hinder evaluation of restenosis due to metallic artifacts with all MRA sequences. Even with detailed knowledge of artifacts, a reliable assessment is possible only in few cases. The severity of artifacts is mainly dependent on stent material (Fig. 5.17) where steel stents disturb imaging more than those from nitinol (Cavagna et al. 2001 Teng et al. 2004). 

Fig. 5.17. Post-stent CE-MRA. Substantial signal loss due to metallic artifacts (a steel containing wall-stent was used). Note typical ring-like extinctions at proximal and distal tips of the stent. While CE-MRA did not really contribute to the problem of in-stent restenosis, ultrasound was normal in this case...

The analysis of metal artifacts has been used extensively to differentiate materials by sources. X-ray fluorescence and neutron activation analysis have both proved valuable in determining elemental concentrations. Native metals, such as gold, contained impurities that could, in some cases, be used to characterize their sources. However, the smelting of ores to recover the metals often changed the concentrations of impurities. Later, as alloys (e.g., bronze and brass) were produced, the compositions were intentionally altered and controlled. In some cases, the re-use of materials or the lack of quality control made the alloy composition quite variable (especially in terms of the trace components). 

Certain ore deposits may partially overlap in their lead isotope composition. In such a case, it might not be possible to decide on the basis of the lead isotope data alone which of the ore deposits in question provided the ore for metal artifacts that have lead isotope compositions that fall into the overlapping space. Sometimes, one of these ore deposits can be ruled out by using trace element data, particularly from gold and silver analyses (6). Lead isotope analyses by themselves can make a negative statement with absolute certainty in a way which chemical analysis can never hope to do. If the lead isotope composition of an artifact falls well outside the lead isotope field characteristic of a particular ore deposit then it is certain that the metal... 

How then the metal artifacts from Troy II compare with those from Kastri on Syros Chemical analyses of 19 objects from Troy II (see also reference 42) revealed that 14 are high tin bronzes (6, pp. 39-40). Tin bronze was not common at this time in Anatolia, but it seems to have been quite abundant in Troy and in Thermi on Lesbos (43). The lead isotope analyses of copper-based objects from Troy show that Troy obtained copper from a surprisingly large number of sources (see also reference 42). 

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