Sustainable conservation of outdoor iron-based artworks by natural corrosion inhibitors

摘要

Environmental protection and preservation of the health of professionals in the Conservation of Cultural Heritage is a key issue to be addressed for a sustainable scientific approach. The development of safe, reliable, non-toxic and long-lasting corrosion inhibitors for the conservation of metallic artifacts has become mandatory for replacing the presently used hazardous materials. In this work new green products derived from natural extracts of some common and widespread plants in the Mediterranean basin were tested as potential corrosion inhibitor for iron-based artworks. The electrochemical properties and the surface chemical composition of the coatings were monitored as a function of corrosion in different media, i.e. in acidic and chlorides solutions, simulating rainwater in a urban polluted context and seaside environment, respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy (HS) were performed both in presence and in absence of the natural products. Experiments were performed as a function of the concentration and of the immersion time. The coating of the iron-based substrates was produced by immersion at room temperature. The surface chemical characterization of the coatings was performed by X-ray Photoemission Spectroscopy (XPS), both before and after submission to the corrosion attacks.