Corrosion inhibitors for the conservation of bronzes and gilded bronzes exposed to the atmosphere

Corrosion inhibitors, associated or not with protective coatings, may be a good solution for planned conservation activities in case of bronze and gilded bronze works of art, such as the Doors of the Baptistery of Florence, the San Marco Horses in Venice or the Marcus Aurelius in Rome. The studies, in the cultural heritage area, have been mainly focused on the use of Benzotriazole, which is a good inhibitor, but it is toxic for people and environment. In this work, non-toxic corrosion inhibitors for bronze and gilded bronze are investigated. The inhibitors have been tested both on non patinated and patinated bronzes, reproducing renaissance leaded bronzes. The experimentation includes electrochemical measurements in artificial rain and 3.5% NaCl solution, short-circuit tests performed on gold/ bronze couples. Materials and surfaces were characterised with and without inhibitive treatments.