Corrosion Protection of Bronze Patina by New Non-Toxic Organic Inhibitors

摘要

From antiquity bronzes have been widely used to produce sculptures and others objects of art. Bronze artefacts are generally covered with a patina. The patina formed in a long term exposition acquired often a certain protective effect of the substrate metal, but a recent increase of air pollution and/or acid rain damage the bronze exposed in urban environment. A method that reinforces a protective effectiveness of patina becomes therefore necessary. In order to preserve metal works from the aggressive atmosphere, organic inhibitors are often required. The inhibiting effects of two non-toxic organic inhibitors: l-phenyl-4-methylimidazole and 1-(p-tolyl)-4-methylimidazole on the patina were examined by potentiodynamic methods and electrochemical impedance spectroscopy as well as spectroscopic methods. The morphology and crystallographic structure of artificially obtained patina without and with inhibitor layer were examined with Scanning Electron Microscopy (SEM) and X-ray Elemental Energy Dispersion Spectroscopy (EDS) analyses. The results of these investigations have shown that both studied inhibitors protect patina in aggressive media.