Electrophoretic deposition of TiO₂ and TiO₂ + CeO₂ coatings on type 304L stainless steel

Electrophoretic deposition (EPD) was employed to coat TiO₂ and TiO₂+CeO₂ on AISI type 304L stainless steel (SS) to improve its corrosion resistance. Coatings were obtained by following three main steps, namely formation of a suspension of the charged TiO₂ particles with addition of CeO₂, deposition of the suspended particles on the electrode under the influence of a dc electric field, and sintering of the particulate deposit at 1073 K for 2 h in vacuum to form a dense and continuous film. The uniform deposits of TiO₂ and TiO₂+CeO₂ formed on the surface shown good sintering characteristics and were characterised using X-ray diffraction (XRD) technique. The electrochemical investigation of the coatings in neutral chloride media was carried out to obtain open circuit potential (OCP) and potentiodynamic anodic polarisation behaviour in order to evaluate their corrosion resistance. The electrochemical parameters shifted towards noble direction for the TiO₂ and CeO₂+TiO₂ coated specimens in comparison with uncoated type 304L SS. The addition of CeO₂ to TiO₂ coating brings about a decrease in passive current density and an increase in the passivation range. The effect was significant at 15 and 20% of CeO₂ addition to TiO₂ coating indicating the stable nature of the coatings.