Datación de pecios de los siglos XVIII y XIX a través de la caracterización de los forros de cobre

Abstract

Compositional and structural analysis of the copper or brass sheathings that are conserved in underwater archaeological sites have allowed us to date different wrecks ships belonging to France, Spain or England. Studies have been done combining metallographic techniques, chemical analysis by spark spectrometry, scanning electron microscopy (SEM), X-ray spectroscopy (EDX) and microhardness testing. The use of copper alloys in sheathings, extended from the first tests carried out on the frigate HSM Alarm in 1761 until the beginning of the twentieth century, always on wooden-hulled vessels. The main objective of the sheathing was to prevent the attack on the bivalve Teredo navalis (mollusca) but also it was possible to reduce biofouling on the hull and increase the speed and maneuverability of ships. The results show a clear evolution of the alloys user for sheathing, from copper alloys with a certain amount of impurities depending on the country of origin, till the appearance of brass alloys and ending with pure copper concentrated by flotation and electro refined.