An Analytical Methodology for the Study of the Corrosion of Ferrous Archaeological Remains in Soils

Abstract

In the context of the cultural heritage, a methodology based on field and laboratory approaches is developed for studying the long-term corrosion of iron. Moreover it has been adapted to the study of archaeological artefacts buried in anoxic soils in the specific case of in situ preservation. The environmental parameters are determined on the archaeological sites and artefacts are collected and characterized using complementary multi-scale techniques. Moreover, laboratory experiments are performed to locate the reaction sites inside the corrosion layer and to identify its electronic properties. The results allow estimation of a low corrosion rate for iron buried in an anoxic soil (under 2 μm/year) and the proposal of a mechanism based on a decoupling of the anodic and the cathodic sites. Then a diagnosis of the alteration state of the samples is established.

Keywords:

• in situ preservation
• anoxic water-saturated environment
• iron corrosion

The authors would like to thank the ANDRA for its financial support. Moreover, we would like to thank Danielle Arribet-Deroin who provided the samples and the city of Compainville. This work has also been performed with the contribution of Pascal Berger, Christian Bataillon, Michael Descostes, Louis Raimbault, and Henning Matthiesen, the DiffAbs team of the synchrotron Soleil and the SUL-X team of the synchrotron ANKA.

Additional information

Notes on contributors

Mandana Saheb

Mandana Saheb has a PhD in Materials Science from Paris Est University. She has been working on the corrosion of archaeological remains in anoxic soils, in the fields of cultural heritage preservation and nuclear waste management. She now has a post- doctoral position at the Laboratory of Archaeomaterials and Alteration Prediction in the French Atomic Energy Agency and the National Centre of Scientific Research.

Correspondence to: Mandana Saheb, SIS2M/LAPA, UMR 3299 CEA/CRNS, France. Email: [email protected], [email protected]

Delphine Neff

Delphine Neff has a MSc/engineering degree in Material Science. She studied the long-term corrosion of iron during her PhD work and graduated from the Compiègne University in 2003. She obtained a research engineer position at the French Atomic Energy Agency where she pursues her research in the field of long term corrosion of iron in various conditions involving soils, marine environments, concrete, and the atmosphere.

Correspondence to: Delphine Neff, SIS2M/LAPA, UMR 3299 CEA/CRNS, France. Email: [email protected]

Eddy Foy

Eddy Foy has a PhD in Solid State Physics and Crystallography from Centrale Paris School in 1999. He has been working on the physical properties of thin films, based on 3d transition metals, grown by MBE. He obtained a research engineer position at the French National Centre of Scientific Research (CNRS) in 2002, where he is in charge of the development of a X-ray generator for X-ray Diffraction and X-ray Fluorescence analyses of samples.

Correspondence to: Eddy Foy, SIS2M/LAPA, UMR 3299 CEA/CRNS, France. Email: [email protected]

Jean-Paul Gallien

Jean-Paul Gallien has a PhD in radiochemistry in relation with the nuclear spent fuel cycle. He specializes in the microanalysis of trace elements using a light ion beam. He also worked on material behaviour under heavy ion irradiation. Since 2010, he has been in charge of corrosion experiments using stable light isotopes.

Correspondence to: Jean-Paul Gallien, SIS2M/LAPA, UMR 3299 CEA/CRNS, France. Email: [email protected]

Philippe Dillmann

Philippe Dillmann is Directeur de Recherche at the French Centre of Scientific Research (CNRS). He is a doctor and engineer in materials science and ‘Habilité à Diriger des Recherches’. He conducts research into archaeometallurgy and archaeometry that deals with the understanding of manufacturing and trade routes of iron based artefacts in ancient societies and on long-term corrosion and conservation of archaeological iron artefacts. He is president of the Working Party 21 of the European Federation of Corrosion, dedicated to the study of corrosion of cultural heritage metals.

Correspondence to: Philippe Dillmann, SIS2M/LAPA, UMR 3299 CEA/CRNS, France. Email: [email protected]