Noninvasive Solution for Electrochemical Impedance Spectroscopy on Metallic Works of Art

Metallic works of art of cultural relevance are continuously subjected to corrosion as the environment becomes increasingly polluted. A fast and simple method to in situ assess the conservation conditions is therefore required. This paper describes the development and performance of dry and gel-based electrodes which can be used to assess the surface conservation state without the need to move the artifacts and which do not cause any damage to them. The electrodes can be used with a portable electrochemical impedance spectroscopy system, without employing electrochemical cells. The proposed solution does not provide all the information that one can obtain using an electrochemical cell, but it can discriminate between protective coatings. It can be used to assess the protective capability of corrosion product layers and natural patinas, and it can therefore enable a noninvasive routine surface assessment to be conducted that could be extremely useful for people working in the field of conservation of cultural heritage.