ABSTRACT
This work presents a comparative investigation using two non-invasive elemental analytical techniques, X-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS), for the chemical characterization of a real case study of underwater-corroded metals: the silver coins of the Spanish frigate “Nuestra Señora de las Mercedes”. A ship loaded with funds and products from the Viceroyalty of Peru, well known to had been sunk by the British Army in 1804 off the coast of Algarve and plundered more than two hundred years later by the commercial company Odyssey Marine Exploration. The combination of both techniques allows overcoming the complexity of the thick patinas covering the coins, compound by corrosion products and the deposits from the seabed. While XRF helps to answer inquiries associated with the conservation and restoration of the metallic pieces, LIBS can solve questions about their core composition and metallurgical techniques employed for their production.
