In Situ Electrochemical Impedance Spectroscopy Measurements and their Interpretation for the Diagnostic of Metallic Cultural Heritage: A Review

• Published in: ChemElectroChem
• Main Authors: Ramírez Barat, Blanca, Cano Díaz, Emilio
• Other Authors: Comunidad de Madrid, Ministerio de Economía y Competitividad (España)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley-VCH 2018
• Subjects: Diagnostics; In situ analysis; Cultural Heritage; Electrochemical impedance spectroscopy; Conservation; North Atlantic
• Online Access: http://hdl.handle.net/10261/188824; https://doi.org/10.1002/celc.201800844; https://doi.org/10.13039/100012818; https://doi.org/10.13039/501100003329

Protecting metallic cultural heritage from corrosion is a major challenge for metal conservators. Electrochemical techniques offer a great potential for monitoring the conservation condition of this type of heritage, providing a powerful tool for designing conservation strategies. For this reason, the application of techniques such as electrochemical impedance spectroscopy (EIS) has aroused increasing interest in recent years, although some difficulties in application and interpretation of the results still keep it from being routine practice. This Review aims to picture the state¿of¿the¿art of using electrochemical impedance spectroscopy (EIS) for the in¿situ monitoring of metallic cultural heritage, focusing on spectra interpretation and different approaches that have been proposed to perform field measurements since the 1990¿s. In the first part of the Review, different cell designs based on the use of liquid or solid electrolytes for in¿situ measurements are reviewed. In the second part, a few general equivalent circuits are proposed as a basis for interpreting results on different metal surfaces after discussing different models proposed in literature. This overview intends to summarize and clarify the key points in the use of EIS, and encourage the use of this and other electrochemical techniques in the field of conservation science, for a better preservation of our cultural heritage. This work was supported by the Spanish Ministerio de Economía y Competividad (projects HAR2011-22402 and HAR2014-54893-R, and grant BES-2012-052716), and GEOMATERIALES 2-CM Program Ref. S2013/MIT-2914 (Comunidad de Madrid). Thanks are due also to Elsevier, ESG, IIC,North Atlantic University Union, Springer and Wiley and Sons forreprint permission of figures from reviewed articles. COPAC groupis a member of the Spanish Network on Science and Technologyfor the Conservation of Cultural Heritage (Techno Heritage). Peer Reviewed