Ricerc@Sapienza

A group of orichalcum Roman coins, from private collections, have been studied for this research. Numismatic examination indicated that they are asses, sestertium and dupondius, minted from Julius Caesar to Nero. Orichalcum is an ancient copper based alloy with a variable percentage of zinc.
The aim of this study was to investigate the process of dezincification from the external layers to the core of the samples. Furthermore, the research was aimed to disclose the real chemical composition of the orichalcum alloy.

A collection of ancient Roman orichalcum coins, i.e., a copper-zinc alloy, minted under the reigns from Caesar to Domitianus, have been characterised using scanning electron microscopy (SEM-EDS) and electron microprobe analysis (EMPA). We studied, for the first time, coins emitted by Romans after the reforms of Augustus (23 B.C.) and Nero (63-64 A.D). These coins, consisting of asses, sestertii, dupondii and semisses, were analysed using non- and invasive analyses, aiming to explore microstructure, corrosive process and to acquire quantitative chemical analysis.

The voltammetry of immobilized particles (VIMP) is applied to describe the solid state electrochemistry of brass.

A selected number of Roman orichalcum coins, from private collections, have been studied. Numismatic analysis indicates that (Crawford, 1974; Sutherland, 1984) they are asses, sestertius and dupondium, minted by Julius Caesar, Augustus and Claudius. The aim of this study was to disclose the chemical composition of the orichalcum alloy, the nature of the patina and corrosion products; orichalcum is an ancient copper based alloy with a variable percentage of zinc (Craddock, 1978). With this aim a multi-analytical approach was involved, i.e.