Ricerc@Sapienza

The aim of this work was to characterize chemical composition of the alloys and corrosion microstructures of Phoenician bronze weapons from the archaeological site of Motya (western Sicily, Italy). For this purpose, some bronze artifacts were selected and studied by the combined use of different analytical techniques, such as scanning electron microscope (SEM-EDS) and electron microprobe analysis (EMPA). Moreover, X-ray maps on cross section of the artifacts were also performed to obtain information about elemental distribution in the different layers. Quantitative analysis from rim to core sections has been acquired using EMPA in order to estimate different composition of major and minor elements of the original alloy. The results revealed that binary (Cu-Sn) and ternary alloys (Cu-Sn-Pb) with some impurities of As compose the weapons. A common feature of quite all samples is represented by dissolution of copper in outermost layers (i.e., decuprification process) as well as widespread presence of chlorine as the main corroding agent. However, different microstructures of the alloys were observed, i.e., an axe shows a matrix of low tin bronze with large and insoluble Pb globules, which undergo oxidation processes, forming oxidized lead compounds on the patina; other artifacts display complex stratified corrosion layers with a periodicity, recognized as the Liesegang effect (Scott, 2006), which is related to the occurrence of chloride compounds. The study of the microstructures and the stratigraphy of these metal artifacts allow having new insights about corrosion process and the nature of the alloys as well as on metallurgical background of Phoenicians. Scott D. A. 2006. Periodic Corrosion Phenomena in Bronze Antiquities. Studies in Conservation, 30(2), 49.https://doi.org/10.2307/1506088