Self-healing ceria-modified coating for corrosion protection of AZ31 magnesium alloy

Highlights: • Modification of hybrid epoxy-silane coating with ceria nanoparticles • Ceria leads to improved and stable corrosion protection of AZ31 • Delay of corrosion propagation in the presence of ceria • Enhanced corrosion protection with low concentration of ceria nanoparticles - Abstract: A hybrid siloxane-based coating was modified with CeO₂ nanoparticles and applied on AZ31. The corrosion protection performance was evaluated via Electrochemical Impedance Spectroscopy (EIS) in 0.05 M NaCl. CeO₂-modified coating showed improved and more stable protective performance compared to the blank coating. Localized healing of the modified coating was studied via Scanning Vibrating Electrode Technique (SVET), Scanning Ion-Selective Electrode Technique (SIET) and Localized Electrochemical Impedance Spectroscopy (LEIS). Addition of ceria led to lower cathodic activity in 0.05 M NaCl and alkalization was kept localized. The CeO₂-modified coating provided corrosion protection, including pre-emptive healing of localized corrosion activity, of AZ31.