Structural and electrochemical properties of the catalytic CeO2 nanoparticles-based PEO ceramic coatings on AZ91 Mg alloy

CeO2 nanoparticles are highly recognized for their catalytic role in various energy applications. The phenomenon of switching between the stable oxidation states (+4, +3) of cerium is considered as the main cause of its catalytic activity. In this report cerium rich ceramic coating was prepared on AZ91D magnesium alloy. From the EDS analysis, it was confirmed that CeO2 particles were preferentially sited in the pores, cracks and the radial zones around the pores. The presence of ceria and cerium based inter-metallic species in the XRD pattern established the generous involvement of the ceria nanoparticles in the PEO reactions. The Raman results showed particular bands related to the catalytic ceria and supported the XRD outcomes. Due to the compact and cerium-rich inner layer due to its optimum catalytic role, the coating prepared for 30 min was found to have the highest corrosion resistance measured through EIS and potentiodynamic polarization experiments. (C) 2017 Elsevier B.V. All rights reserved.