Microstructure and long-term corrosion of archaeological iron alloy artefacts

International audienceThe smithing skills of craftsmen in the western Mediterranean during the early Iron Age can be determined by studyingthe microstructure of oxidised iron items. While some ghost structures have already been identified in densecorrosion products, their formation has not always been explained. Four objects from southern France were analysedusing optical microscopy, X-ray diffraction, micro-Raman spectroscopy and field-emission scanning electron microscopycoupled with energy dispersive spectroscopy and electron backscatter diffraction. The role of microstructure,grain boundaries, cracks, species diffusion through oxides in soil corrosion and the initial microstructure are discussed.An additional parallel degradation mechanism (graphitisation) was experimentally revealed