Effect of the Deposition Temperature on the Corrosion Stability of TiO2 Films Prepared by Metal Organic Chemical Vapor Deposition

The aim of this study was to investigate the influence of the deposition temperature on the corrosion stability of the TiO2 layers. A metal organic chemical vapor deposition (MOCVD) system was used to grow TiO2 films at three different temperatures: 300°C, 400°C and 500°C. The electrochemical behavior of the films was assessed through electrochemical impedance spectroscopy (EIS) measurements, potentiodynamic polarization curves and chronoamperometric curves. The tests were performed in a sodium chloride solution at room temperature. The porosity of the different films was also determined using an electrochemical method. The morphologies of the coatings were characterized by field emission scanning electron microscopy (FE-SEM) through surface and crosssectional images and X-ray diffraction (XRD). The results pointed to a marked effect of the deposition temperature on the structure of the TiO2 layers. The structure of the films was closely related to their corrosion stability. The film formed at 400°C yielded the highest corrosion resistance.