Using the most advanced techniques for analyzing the surfaces of materials, a team of researchers has shed light on the coin-making practices of the Roman Empire and the manner in which Roman coins have corroded over the past 2,000 years.
The study by Lehigh chemical engineers and materials scientists demonstrated that low-energy ions, x-rays and laser lights can be used to analyze archaeological objects without damaging them. And it yielded clues about the environment to which the coins, and the people who handled them, were exposed.
The group, which studied five Roman coins, reported its findings in the journal Applied Surface Science in an article titled “Analysis of corrosion layers in ancient Roman silver coins with high resolution surface spectroscopic techniques.”
The paper’s authors included Israel E. Wachs, the G. Whitney Snyder Professor of chemical and biomolecular engineering, and Michael R. Notis, professor emeritus of materials science and engineering. The lead author, Christopher J. Keturakis, earned a Ph.D. in chemical engineering from Lehigh in 2015.
The researchers used three surface spectroscopic techniques to determine the composition of the highly reactive outer layers of the coins, where corrosion occurs. One of these, high sensitivity-low energy ion scattering (HS-LEIS) spectroscopy, had not previously been used to study archaeological specimens.
The paper was also coauthored by Notis’s grandson, Ben Notis, a senior at Brandeis University; Alex Blenheim, a former chemical engineering student intern at Lehigh who now works for Campbell in Camden, N.J.; and senior Lehigh research scientists Alfred C. Miller and Rob Pafchek.
Source: Lehigh University