Surface and interface characteristics of CeO2 doped Al2O3 coating on solution treated and peak aged AZ91 Mg alloy

The present study deals with the development of a ceramic based coating on AZ91 Mg alloy. D-gun thermal spray technique is used to deposit these coatings. The work is divided into two explorations; (i) the effect of substrate (AZ91 alloy) microstructure and (ii) the effect of CeO2 doping in Al2O3 coating. The coating quality is judged by recording hardness (H), elastic modulus (E) and H/E ratio. The microstructural, metallurgical and mechanical properties were recorded using SEM/EDS, XRD and nanoindenter, respectively. The results indicate that there is optimality in the doping concentration of CeO2 in Al2O3. Moreover the coatings deposited on solution treated alloy exhibit superior properties. The improved mechanical response is attributed to the development of new phases.