TiO2 NANOSTRUCTURED COATING OBTAINED VIA TERMOPHORETICAL DEPOSITION OF FLAME SYNTHETIZED NANOPARTICLES

A one-step method to produce coatings of TiO2 nanoparticles on metallic substrates is presented. TiO2 nanoparticles have been synthesized by Aerosol Flame Synthesis (AFS) and deposited through the mechanism of thermophoresis onto aluminum alloy substrates. The deposition system is constituted by a rotating disc, in order to increase the heat exchange and to promote a uniform distribution of the nanoparticles on the substrates. A fuel-lean flame is used as flame reactor. The average dimension of the nanoparticles is about 5 nm. Three different coatings have been obtained by varying the time of exposure of the substrates into the flame. A full experimental campaign, including SEM observation, thickness detection obtained via confocal microscopy and Electrochemical Impedance Spectroscopy (EIS) has been conducted, in order to characterize the surface and the electrochemical behavior of the coatings. Results show an improvement of the electrochemical behavior, since the deposition is uniform and the coating does not present agglomerates on the aluminum alloy substrates.