Electrochemical Characterization of Archaeological Metals

Electrochemical characterisation has emerged as a vital toolkit for understanding the corrosion, preservation and metallurgical history of artefacts recovered from archaeological contexts. By monitoring current–potential relationships and impedance responses, researchers can identify the nature and stability of corrosion products, evaluate protective patinas or coatings, and assess the long-term behaviour of alloy constituents under varied environmental conditions. Techniques such as potentiodynamic polarisation and electrochemical impedance spectroscopy provide quantitative measures of corrosion rates and barrier properties, while specialised approaches like voltammetry of microparticles generate electrochemical “fingerprints” of discrete corrosion phases. Together with microscopy and spectroscopic analyses, electrochemical methods enable non-destructive or minimally invasive investigations that preserve valuable objects. This interdisciplinary strategy informs conservation protocols, aids in selecting stabilising treatments, and offers insights into ancient manufacturing processes and trade routes by revealing alloy composition and degradation patterns. Globally significant case studies range from Roman coinage to Bronze Age weaponry, demonstrating the potential of electrochemistry to bridge materials science with cultural heritage and ensure the informed stewardship of metallic artefacts.

Research from Nature Portfolio

Recent studies have explored the influence of natural patinas and modern protective coatings on archaeological bronze and copper-tin alloys. By employing potentiodynamic polarisation, electrochemical impedance spectroscopy and cyclic voltammetry, researchers quantified the barrier performance of aged patinas versus freshly applied coatings. Results indicate that combined patina-coating systems can reduce corrosion currents by orders of magnitude, providing scientific guidance for conservation treatments that maintain original surface features.

A foundational investigation integrated focused-ion-beam field-emission scanning electron microscopy with voltammetry of microparticles and electron microprobe analysis on silver-based Roman coins. This multimodal approach elucidated subsurface alloy stratigraphy and identified corrosion-induced dealloying pathways. The electrochemical fingerprints derived from microparticle voltammetry reliably distinguished copper-rich corrosion phases and informed models of ancient silvering techniques.

Electrochemical Characterization of Archaeological Metals publication trend

The graph below shows the total number of articles in electrochemical characterization of archaeological metals across all publications each year (not limited to Nature Index journals).

Technical terms

Potentiodynamic polarisation: Electrochemical technique in which potential is swept and current response recorded to determine corrosion rates and reaction kinetics.

Electrochemical impedance spectroscopy: Method measuring system impedance over a range of frequencies to characterise film resistance, capacitance and charge-transfer processes.

Voltammetry of microparticles: Solid-state voltammetric approach where powdered sample particles produce distinct voltammograms, enabling identification of corrosion phases.

Tafel slope: Parameter derived from the logarithmic plot of current versus overpotential, indicative of reaction mechanisms and rate-determining steps.

References

1. Evaluation of the corrosion resistance of bronze patina or/and protective coating on the surface of the archaeological coins. Scientific Reports (2025).
2. FIB-FESEM and EMPA results on Antoninianus silver coins for manufacturing and corrosion processes. Scientific Reports (2018).
3. Characterization of corrosion products on contemporary bronze artwork by using voltammetry of microparticles and PCA. Microchemical Journal (2024).
4. A methodological approach to estimate soil corrosivity for archaeological copper alloy artefacts. Heritage Science (2018).
5. Corrosion phenomena and patina on archaeological low-tin wrought bronzes: New data. Journal of Cultural Heritage (2022).