Production and Characterization of Nano-tio2 Coatings on Aluminium Alloy Surfaces with Improved Anticorrosion Behaviour

Abstract

This paper presents a one-step method for the coating of aluminium alloy surfaces with titania nanoparticles. This method is based on a highly controllable and tunable technique for the production of thin coating layers of TiO₂ nanoparticles by aerosol flame synthesis and direct thermophoretic deposition. More specifically, few nm diameter TiO₂ nanoparticles in the form of anatase are synthesized by flame aerosol and directly deposited as thin film by thermophoresis on aluminium alloy AA2024 samples. Submicron coatings of different thicknesses were produced by changing the total deposition time. A thermal annealing treatment was fine-tuned using UV-Vis Absorption spectroscopy and applied in order to improve the adhesion of the coating on the aluminium surface.
Electrochemical polarization measurements were performed to evaluate the corrosion resistance of coated aluminium substrates. The electrochemical polarization curves showed a significant increase of the corrosion potential of coated substrates with respect to the bare aluminium and a decrease in the current density. The coatings produced with higher deposition time and so greater thickness showed the best performances in terms of corrosion resistance.