Galvanized steel pre-treated with hybrid film cured by UV : influence of photoinitiator concentration on the corrosion resistance

Several coatings have been proposed as an alternative to replacement processes based on hexavalent chromium. Among them stand out the hybrid films. Some hybrids films, with modified composition by the addition of photoinitiators, can be cured by ultraviolet system (UV). The UV cure is the instantaneous conversion of a reactive liquid in a solid induced by radiation, starting from the polymerization and cross-linking reactions of the chemical species. In order that reaction takes place through the action of UV radiation, it is necessary to add, in the composition of the hybrid film, a substance sensitive to this radiation called photoinitiator. The aim of this work is the preparation and characterization of hybrid films, cured by UV, from TEOS and TMSPMA alkoxide precursors, with addition of photoinitiators with different concentrations (1 and 2%) and without photoinitiator on galvanized steel. The films were characterized concerning the morphology, physicochemical properties and electrochemical behavior. The presence and the increase of photoinitiator concentration on hybrid films improved corrosion resistance of the system