IPERION HSIntegrating Platforms for the European Research Infrastructure ON Heritage Science
Technique: Electrochemical impedance spectroscopy

Electrochemical system

The electrochemical system is composed of a portable potentiostat/galvanostat/ZRA (Gamry Ref600, including DDS to perform EIS from 10 µHz to 1 MHz, and floating ground, accuracy of ± 1 mV and ± 10 pA) adapted for field operation by means of batteries; a gel polymer electrolyte (G-PE) electrochemical cell, with a 3-electrode configuration and possibility to tailor the selection of electrolyte, specifically developed for non-destructive analysis of cultural heritage assets; and a positioning/supporting system allowing to perform analysis on different geometries, positions (even upside down), surface textures, etc. Different electrochemical techniques can be carried out, such as polarization resistance, polarization curves or electrochemical impedance spectroscopy (EIS). The standard measured area is a circle of 2 cm diameter, but the cell can be adapter to larger or smaller areas if needed.

Potential Results

The system offered is suitable for the study of metallic heritage, covered by corrosion layers, patinas and/or protective coatings (paints, varnishes, waxes, etc.). The electrochemical response of the system allows to obtain corrosion rates; to quantitative measure the protective properties of the patina/corrosion layer/coating; to compare different protection systems proposed by the conservators-restorers or developed by researchers; to follow up the evolution over time and ageing of these coatings or patinas; and to detect the failure of the protection systems before evident corrosion takes place on the substrate, therefore allowing to apply a new conservation treatment before actual damage occurs to the heritage artefact or monument. The G-PE cell allows to measure in-situ on the objects. It allows to measure in all positions (even upside down), no rough or smooth surfaces, and in flat and slightly curved areas. The electrolyte composition can be tailored to measure corrosion behaviour in different scenarios, such as objects exposed to different atmospheres (marine, urban, industrial or rural) or specific compositions for metals of different sensitivity.