Application of sol-gel method for the conservation of copper alloys

In the present study, SiO2 coatings are presented as an alternative to the traditional ones, used in conservation of metals. The preparation of methyl-modified nanosilica coatings by the sol-gel technique to protect the external surface of copper alloys is discussed herein. The methyl-modified silica sols were obtained by mixing of 3% SiO2 sol solution with hexamethyldisilozane (HMDS). The surface of brass and bronze specimens was coated by dip-coating technique. The structural features of the coatings were evaluated by FTIR spectroscopy. The hydrophobicity of the surfaces was investigated by contact angle measurements. The surface morphology changes of bare and coated specimens prior and after photochemical ageing were evaluated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Potentiodynamic measurements were obtained in order to compare corrosion parameters of the coatings.