| Abstract [eng] |
Metals conservation involves the preservation of cultural objects. The goal is to preserve objects while retaining evidence of their cultural context and integrity. Ideally there should be a minimum change to an object while achieving this and restoration to the former state is rarely carried out. While preservation appears to be a straight forward materials science problem, involving elucidation of the structure and corrosion of metals to develop conservation procedures that prevent or control corrosion, it is constrained by ethics, aesthetics, and cultural contexts that may complicate, constrain, and ultimately direct preservation strategies. The goal of conservation is the preservation of an object using minimum intervention. Research into the corrosion and conservation of historic and archaeological metals is developing significantly due to the increasing contribution of dedicated specialists that have a specific focus and the challenges of large complex objects. Copper, bronze, brass and steel were commonly employed in cultural heritage objects. They were commonly used in cultural heritage objects such as sculptures, other outdoor decorative items, swords, details of appearing, jewelry, etc. Corrosion inhibitors, polymer and synthetic wax coatings are used for the conservation of metal objects. However, these methods do not provide successful preservation of metals for a longer term. Researchers are mainly focused on obtaining long–term, anticorrosion, protective coatings and methods that could replace toxic solutions used in conservation and restoration of metals. Sol–gel derived coatings have already been applied for surface protection of metal specimens. However, the properties of the coatings may diverge on different metal substrates. Namely, sol-gel method is highly perspective for obtaining thin, hydrophobic, anticorrosion coatings with great chemical stability, oxidation control and enhanced corrosion resistance on metal substrates. Moreover, sol–gel method is not toxic, has low costs in the process and equipment, has no limits in the size or shape of the substrates and etc. In order to compare the efficiency of proposed sol-gel method metal substrates were also coated with substances that are used in conservation of metals: Paraloid B72, Plexisol P550-40, polyvinyl butyral (PVB), Paraloid B67, Cosmolloid H80 and Antik Patina. The hydrophobicity of obtained coatings was evaluated by contact angle measurements. The morphological features of just obtained and photochemically aged coatings on the metal substrates were determined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The corrosion parameters were obtained by potentiodynamic polarization measurements. |
