“In-situ Electrochemical Impedance Spectroscopy measurements on immovable cultural heritage

In order to understand the atmospheric corrosion mechanisms of indoor and outdoor metallic artefacts of artistic and historic interest and to develop tailored, long lasting conservation methodologies, the characterization of surface conditions of the artefacts is mandatory. In situ Electrochemical Impedance Spectroscopy (EIS)may be employed to investigate the phenomena involved at the electrochemical interfaces among the various corrosion products and to assess and predict their corrosion behaviour. The results of a monitoring campaign on two case studies are reported: i) iron bar chains exposed indoor from over 500 years in the Notre Dame Cathedral in Amiens (France), ii)large weathering steel monument exposed outdoor from tens of years in Ferrara.