Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

Abstract

Traditional electrochemical techniques, such as linear polarization resistance (Rp), and electrochemical impedance spectroscopy (EIS), cannot be applied to gilded bronzes, as it may not be possible to interpret the results obtained due to the bimetallic nature of the studied material. The measurement of the macrocouple current generated by the gold/bronze galvanic couple can be used as an indicator of degradation processes. Nevertheless, this measurement cannot be performed directly on the original artifacts due to the systematic presence of short-circuits between the two metals. In the present work the use of galvanic sensors is proposed as a possible solution for the monitoring of gilded bronze artefacts. The sensors have been designed to simulate real gilded bronze surfaces in terms of composition and stratigraphy and have proved to be a reliable diagnostic tool for the in situ monitoring of the rates of deterioration of gilded bronze surfaces and to test new conservation treatments. Their set-up and application is reported and their performances discussed.

Corrosion investigation of fire-gilded bronze involving high surface resolution spectroscopic imaging

“…After cleaning, conservation actions must be implemented on gilded bronze artworks to ensure their long-term corrosion protection. Both preventive techniques, such as microclimate control [9,16] and use of coatings and inhibitors [12,17,18], were investigated. In order to help microclimate control, specific sensors based on the measurement of galvanic currents in gold/bronze couples proved to be useful in finding the most suitable climatic parameters which ensure negligible corrosion rates [16].…”

Atmospheric corrosion of fire-gilded bronze: corrosion and corrosion protection during accelerated ageing tests

“…Both preventive techniques, such as microclimate control [8,17]) and use of coatings and inhibitors [11,18,19], were investigated. In order to help microclimate control, specific sensors based on the measurement of galvanic currents in gold/bronze couples were found useful for finding the most suitable climatic parameters to guarantee negligible corrosion rates [20].…”

Corrosion Monitoring in Atmospheric Conditions: A Review

“…Bronze substrate was separated from a golden layer by corrosion products (patina) to simulate the actual state of historical gilded bronze objects and to avoid short circuits between the gilding and substrate. The authors reported stable and reliable behaviour by the sensors, and their ability to measure even under 15% RH [33].…”

“…Goidanich et al proposed a sensor based on the galvanic principle to monitor the corrosion of gilded bronze objects in museums [33]. Bronze substrate was separated from a golden layer by corrosion products (patina) to simulate the actual state of historical gilded bronze objects and to avoid short circuits between the gilding and substrate.…”