Copper-based coins of the Roman Republic

Chemical Composition of Copper-Based Coins of the Roman Republic,... 

Twenty-two copper-based coins of the Roman Republic were analyzed for Fe, Co, Ni, Cu, Zn, As, Ag, Sn, Sb, and Pb by using X-ray fluorescence according to the procedures described by Carter and Booth (11). Generally, X-ray fluorescence determines elements only in a thin surface layer, about 5-10 xm deep, so it was necessary to clean coins for analysis in such a way that the surface layer was as representative of the entire coin as possible. First, the coins were cleaned by electrolytic reduction in a hot solution of sodium carbonate. Next, the coins were abraded in an air stream containing finely divided aluminum oxide powder to remove about 10 to 15 xm of metal. Carter and Booth described the cleaning procedure in detail as well as the X-ray fluorescence parameters (11). 

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