The fabrication, characterization and electrochemical corrosion behavior of Zn-TiO2 composite coatings

Metal-nanoparticle composite coatings improve the hardness, wear resistance and corrosion resistance properties of metal coatings. In this work, TiO2 nanoparticles were chosen as second-phase particles to generate anticorrosive Zn composite coatings. The TiO2 nanoparticles were dispersed in a Zn plating solution to co-deposit them with Zn. The Zn-TiO2 composite coatings were then characterized by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffraction methods. The presence of TiO2 particles in the composite was confirmed by SEM images and EDS spectra. The Zn-TiO2 composite coatings incorporated with different amounts of TiO2 particles were tested for corrosion performance by polarization and electrochemical impedance spectroscopy, and the dissolution behavior of the coatings that had been immersed in corrosive media for a long time was studied. Improved corrosion resistance properties of the Zn-TiO2 composite coatings were confirmed by polarization studies, fitted Nyquist plots, an increase in phase angle and a shift in the R-ct characteristic peak of the Bode plot.