Development, characterization and evaluation of TiO2/Nb5+ thin films with potential for corrosion prevention of AISI 304 steel in acid medium containing chloride ions
摘要
TiO2/Nb5+ film was prepared and deposited on 304 steel and preventive its potential for corrosion was evaluated. The film was obtained by the sol–gel method, and its deposition by the dip-coating process has been followed by thermal treatment. XRD results with Rietveld refinement revealed the occurrence of isomorphic substitution and predominance of anatase phase. Scanning electron microscopy confirmed the deposition of film on substrate. Corrosion properties of the TiO2/Nb5+ layer was determined by open-circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Polarization curves showed a corrosion current of 129.72 μA for 304 steel without coating, which was larger than that observed for the samples recovered with TiO2/Nb5+ films (9.00 μA). EIS revealed high charge transfer resistance in the molar ratio of 1 to 5% compared to the uncoated 304 steel, highlighting the protective effect of TiO2/Nb5+ films against corrosion.
Graphical abstract