Study of iron sulphides in long-term iron corrosion processes: Characterisations of archaeological artefacts

Sophie Grousset (1) , Marine Bayle (2, 1) , Alexandre Dauzeres (3) , Didier Crusset (4) , Valérie Deydier (4) , Yannick Linard (4) , Philippe Dillmann (2, 1) , Florence F. Mercier-Bion (2, 1) , Delphine D. Neff (2, 1)

1 IRAMAT - LMC - IRAMAT - Laboratoire Métallurgies et Cultures
2 LAPA - UMR 3685 - Laboratoire Archéomatériaux et Prévision de l'Altération
3 IRSN/PSE-ENV/SEDRE/LETIS - Laboratoire d'étude et de recherche sur les transferts et les interactions dans les sous-sols
4 ANDRA - Agence Nationale pour la Gestion des Déchets Radioactifs

Iron sulphides are observed on long term anoxic corrosion profiles of iron artefacts. The archaeological nails studied came from two terrestrial sites (Glinet and Raadhuspladsen) and a subaquatic one (Arles-Rhône 3). Greigite (Fe 3 S 4) and/or mackinawite (FeS 1−x) are observed at the outer border of the corrosion product layer. The presence of mackinawite is discussed relatively to the establishment of stable anoxic burial conditions. The nails from the subaquatic site present pyrite globules in the transformed medium. The formation of pyrite (FeS 2) is attributed to the proximity of wood. The iron sulphides formation may also be explained by the presence of sulphate-reducing bacteria in the burial environment.

Keywords: B Raman spectroscopy; B SEM; A Iron; A Steel; C Microbiological corrosion; Sulphuric acid

Domains: Material chemistry; Chemical Sciences

Sophie Grousset, Marine Bayle, Alexandre Dauzeres, Didier Crusset, Valérie Deydier, et al.. Study of iron sulphides in long-term iron corrosion processes: Characterisations of archaeological artefacts. Corrosion Science, 2016, 112, pp.264 - 275. ⟨10.1016/j.corsci.2016.07.022⟩. ⟨cea-01377025⟩