Surface, Elemental and Electrochemical Characterizations of Ancient Coins By Non – Destructive Techniques

The cultural heritage field represents a witness to artifacts values in a continuous evolution, it strongly influences our sense of identity and our behavior as people. To protect these archaeological treasures, different conservation and restoration methods are required. Considering the field of priceless artifacts, our research direction led us to preliminary studies of metallic coins from 20^th century through non–destructive techniques. Copper–based coins were subjected to the surface characterization through optical microscopy (OM) in transmitted light, elemental composition analysis using Wavelength Dispersive X-ray Fluorescence (WDXRF) and electrochemical corrosion using Tafel extrapolarization technique. The microscopic investigations showed that the patina layer is due to presence of copper content in coins composition confirmed by X-ray fluorescence spectroscopy technique. Also, the electrochemical tests disclosed different corrosion rate according to each chemical composition of coins. This study provide a broad overview of ancient coins to preserve their value in the future.