Debasement of Roman Silver coinage

The quality of ancient silver coinage is often seen as a comment on the fiscal health of the issuing states. This is nowhere more apparent than with Roman coinages, which witnessed debasements during the first three centuries of our era. Most Roman silver coins were produced from an alloy of Ag and Cu. This enabled Roman mints to disguise debasements from the general public by exploiting the dissimilarity between the electrode potentials of the two metals.The blanks for the coins were cast, and they were kept or reheated at red heat to oxidise the copper at the surfaces of the blanks. The copper could then be stripped out of the alloy by soaking in an acid. This left a honeycomb structure of nearly pure silver at the surface of the blanks. We proposed to apply Neutron Tomography on IMAT in order to visualise in 3D the presence of the Ag layer arising from Cu depletion.