engleski

Protection of patinated bronze in polluted environment

In protection of historical and cultural artefacts, only methods that do not change the visual appearance of the artefact can be applied. It is also very important to preserve both the bronze substrate and the patina layer. For this reason only few of the corrosion protection methods may be used, such as corrosion inhibitors or waxes. The aim of this work is to study the possibility of protection of patinated bronze by corrosion inhibitor/wax system. For this purpose two azole type inhibitors and carnauba wax were examined. Since the studies can not be performed on cultural and historical objects, patina similar to patina naturally formed in marine environments was synthesised electrochemically. Another type of patina was obtained by a chemical method used for artificial patination of artistic objects. Studies were performed in a solution presenting rainwater in polluted costal areas: 0.2 g/L Na2SO4 + 0.2 g/l NaHCO3 + 0.2 g/L NaNO3 + 0.2 g/L NaCl at pH=5. The protective effect of inhibitor/wax system was examined by polarization measurements and electrochemical impedance spectroscopy. The results obtained indicate that azole inhibitor/carnauba wax system efficiently protects both patina and the underlying bronze. Subsequent Raman and SEM/EDS analysis of corrosion products gives better insight into morphology change of the studied patinas.

patina protection; wax; corrosion inhibitor

nije evidentirano