Green protectives on corroded copper artworks: Surface characterization and electrochemical behaviour in simulated acid rain

The protective effects of decanoic acid (HC10) and sodium decanoate on naturally corroded copper-based artworks in synthetic acid rain (pH 3.1) were evaluated and compared to those of benzotriazole (BTA). Surface characterization (by colorimetry, optical microscopy, SEM, contact angle and Raman spectroscopy) was coupled with open circuit potential and potentiodynamic measurements. The samples used were copper cladding from the roof of St Martin's Church in Metz (France) and, for comparison, bare copper specimens. This study demonstrated that HC10 may represent an eco-friendly and efficient alternative to the use of BTA for maintaining the naturally formed patinas of copper-based artworks exposed outdoors.