The Fontanamare Discovery (Sardinia coast, Italy), A Case of Underwater Corrosion of Bronze Coins

Abstract

The study reported the analytical approach on nine coins found in the wreck A of Fontanamare for understanding the complex corrosion processes that take place in underwater conditions. Optical microscopy (OM), combined with micro-Raman (µ-Raman) spectroscopy, and X-ray diffractometry (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM + EDS) were used to analyse the nature and the microstructure of the corrosion patina in comparison with the non-degraded state of coins. Three main type of corrosion patina based on copper, lead chloride and carbonate were identified: white-green, black and the obtained results for understanding the complex corrosion processes that take place in underwater conditions.