The use of gels in localized dechlorination treatments of metallic cultural heritage objects

Abstract

Gels were used to perform localized dechlorination treatments on ferrous or copper alloy archaeological objects. Agar gel (3%w) was used as a medium for the electrolyte, a 1%w KNO3 solution. Localized electrolysis with gel was carried out using the same parameters as immersion electrolysis. To determine the end of treatment, two tools were validated: determining the quantity of chlorides present in the gels by XRF and monitoring the oxygen consumption of an object before and after treatment. This study shows that the technique results in the efficient extraction of chlorides. In the case of the stabilization of composite objects or for the localized treatment of copper objects, the use of a localized electrolytic gel treatment is a new effective solution proposed to conservators.