The tribological and corrosion behavior of TiO2 coatings deposited by the electrophoretic deposition process

TiO2 coatings have recently been used as corrosion resistant materials to protect metals in several environments. In this study, the microstructure, phase composition and morphology under different voltages (20, 30 and 40 V) were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The coating corrosion performance was examined by potentiodynamic polarization in 3.5 wt% NaCl solution. Experimental findings indicate that the thickness and cracks of the coating rise by increasing voltage. Energy dispersive X-ray spectroscopy results show that the atomic ratio Ti/O of the coating has an almost constant ratio. Obviously, the defects and cracks on the deposited coatings resulted in corrosive attack due to a considerable increase of the corrosion current density noticed during potentiodynamic polarization experiments. The film produced under 30 V exhibited the lowest corrosion current density ( i corr ) value of 0.21 mu A cm(-2) as well as the lowest corrosion potential ( E corr ) value of -111.89 mV, which was attributed mainly to the significant decrease of micro-pore density in the coating.