Fabrication of corrosion-resistant Al2O3-CeO2 composite coating on AA7075 via plasma electrolytic oxidation coupled with electrophoretic deposition

Al2O3-CeO2 composite coating was fabricated on AA7075 by combining plasma electrolytic oxidation (PEO) with electrophoretic deposition (EPD). CeO2 nanoparticles are electrophoretically incorporated into the plasma electrolytic oxidized Al2O3 coatings by the synergetic effect of PEO and EPD processes. The passivation behavior of Al2O3 and inhibiting nature of CeO2 have been studied by the electrochemical corrosion analysis in 3.5 wt% NaCl solution and salt spray corrosion test (SSCT) in 5 wt% NaCl as per ASTM standards. The results showed that the Al2O3-CeO2 composite coating via PEO coupled EPD significantly improved the corrosion resistance (~103 times higher Rp) compared to the plasma electrolytic oxidized Al2O3 coating.