Investigation of the microstructure and corrosion performance of a nanostructured titania-containing hybrid silicate film on mild steel

A pre-treatment system consisting of a nanostructured titania interlayer loaded with an inhibitor and a hybrid silicate film deposited on the TiO2 layer is shown to provide protection against active corrosion of mild steel. A nanostructured TiO2 interlayer was prepared on the mild steel surface via controllable hydrolysis of titanium alkoxide. To further improve this pre-treatment, the hybrid silicate film was synthesized from tetraethylorthosilicate and 3-glycidoxypropyltrimethoxysilane precursors. The morphology and structure of the titania interlayer and hybrid silicate film were characterized with atomic force microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques. The corrosion performance of the coatings was examined using electrochemical techniques, including potentiodynamic scanning and electrochemical impedance spectroscopy. The TiO2 nanostructure calcinated/inhibitor/hybrid silicate system shows enhanced corrosion performance, as confirmed by impedance and polarization measurements.