Aarhus University Seal / Aarhus Universitets segl

Gry Hoffmann Barfod

Non-destructive identification of surface enrichment and trace element fractionation in ancient silver coins

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

A common issue in non-destructive surface analysis of historical silver coins is depletion of Cu from the near-surface areas, which in turn results in higher Ag content at a coin’s surface. This paper reports a non-destructive analytical strategy using µXRF for identification of Ag and Cu surface enrichments and depletions by comparing peak intensity ratios of Ag Kα/Ag Lα, Cu Kα/Ag Kα and Cu Lα/Ag Lα for coins and Ag-Cu standards of similar composition. Our characterization of coins from different contexts and chronologies shows that a multi-standard approach provides the most reliable identification of surface enrichment of Ag and depletion of Cu. Coins possessing Ag surface enrichment were further analysed with LA-ICP-MS to determine any differences in trace element composition between the cores and surface of the coins. We show that the near-surface regions of these coins are enriched in Au and depleted in Co, Ni, As, and Pt relative to their cores. These systematics allow for a more robust assessment of the degree of silver coin surface alteration critically important in measuring the original composition of historical silver coins.
TidsskriftNuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
Sider (fra-til)11-20
Antal sider10
StatusUdgivet - sep. 2020

Se relationer på Aarhus Universitet Citationsformater

ID: 188930442