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.