Structure stability and corrosion resistance of nano-TiO2 coatings on aluminum in seawater by a vacuum dip-coating method

A stable nano-TiO2 coating was prepared by vacuum dip-coating TiO2 sol-gel onto the anodized aluminum surface. The effect of vacuum dip-coating method and anodization pretreatment on compactness and stability of the coatings was proved. The structure and composition of the coatings were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicate that the surface of coatings is uniform and compact, with high load capacity. The particles of TiO2 anatase is filled into the Al2O3 nano-pores formed by anodization. The electrochemical measurements show that the nano-TiO2 coatings significantly decrease the corrosion currents densities (icorr), as simultaneously increased the values of polarization resistance (Rt) of aluminum. It indicates the nano-TiO2 coatings exhibit excellent anticorrosion properties in sterile seawater at the room temperature.