Iron Age and Roman copper alloys from northern Britain

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source• a link is made to the metadata record in Durham E-Theses• the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. of peaks in the distribution of zinc and tin contents that represent specific alloy types which were commonly produced. The largest peak relates to the commonest alloy: bronze. The second peak relates to brass and the third to copper. All the remaining analyses fall into a diffuse area between the bronze and the brass peaks, and these are referred to by the modern term gunmetal.It is clear that copper alloys were recycled and that some care was taken over the ways in which this occurred. The lack of low zinc brasses shows that this alloy was rarely recycled on its own. If brass was recycled then it was always mixed with some bronze. The proportions of bronze and brass that were mixed varied widely as there is no distinct peak within the distribution of the zinc and tin contents of gunmetals.The thesis uses this overall view of Roman copper metallurgy (and that derived from previous work) to examine changes in alloy production and use. The results (interpreted in the light of metallurgical theory and practice, and of wider archaeological theory and data) challenge many of the traditional accounts of chronological and cultural change, and of the deposition processes operating in the Roman period.

Composition and microstructure of Roman metallic artefacts of Southwestern Iberian Peninsula

“…A similar instance was found on a leaded bronze handle with a Centaurus from a ritual vase at Canas de Senhorim [3]. The brass sheet with high contents of lead and tin is an exception among Roman metal [24], probably resulting from the use of undifferentiated scrap.…”

“…A high lead content is more likely to produce cracks on hammering due to the insolubility of lead in the Cu-Zn solid solution. In fact, Roman copper alloys from Northern Britain show an almost absence of sheet metal with more than 1 wt% lead [24]. The composition of Roman artefacts in the Lusitania province, namely from Monte Molião, Cidade das Rosas, Canas de Senhorim and Castanheiro dos Vento, was compared in Cu-Sn-Pb and Cu-Zn-Pb diagrams (Fig.…”

Roman Copper Alloys: Analysis of Artefacts from Northern Britain

“…A recent programme of analysis was devised to address these limitations (Dungworth, 1995). In particular, it was hoped that the systematic analysis of samples from a range of artefacts from different archaeological contexts and different sites would provide a more detailed picture of Roman Cu alloy use as a whole.…”

“…In the late 1st century  bronze was joined by brass (Craddock, 1978) and these two alloys were mixed together to produce mixed alloys containing Cu, zinc (Zn) and Sn (these alloys are often known by the modern term gunmetal). The simultaneous variation of two different additions to the Cu has led many to represent bronzes, brasses Only those artefacts with at least 15% Sn are shown here (data from Dungworth, 1995). : Mirrors; : non-mirrors.…”

The use of Hand-Held XRF for investigating the composition and corrosion of Roman copper-alloyed artefacts

“…These high iron levels may, in part, originate from impurities in the copper ore. High concentrations of iron in Roman alloyed artefacts have been previously reported [20]. For instance, dupondi and sestertii, early Roman brass coinage, had higher iron content than contemporary bronzes [15].…”