Hybrid PEO/sol-gel coatings loaded with Ce for corrosion protection of AA2024-T3

Plasma electrolytic oxidation (PEO) has been targeted as an eco-friendly alternative technology to conventional chromic acid anodizing (CAA) for corrosion protection of aluminium alloys in the aircraft industry. However, PEO implies high energy consumption. Flash-PEO coatings (≤10 μm) produced short treatment times (≤ 5 min) constitute a feasible way overcome this limitation. Nevertheless, long-term resistance is compromised, thus requiring novel sealing post-treatments. The present work studies effect stand-alone hybrid sol-gel (HSG) and Ce-doped (HSGCe) post-treatment evaluate on alloy (AA) 2024-T3. characterization PEO, HSG, HSG-Ce was performed by scanning electron microscopy, X-ray diffraction, water contact angle, dry adhesion tests (ISO 2409), optical profilometry Fourier transform infrared spectroscopy. behaviour assessed electrochemical impedance spectroscopy up 21 days (3.5 wt% NaCl). Active immersion artificially scratched coatings. Present findings reveal that low-energy-cost were successfully formed AA2024-T3 alloy. Both HSG homogeneously Flash coating. Regarding resistance, showed significant scratch during 3.5 NaCl. results suggest that, while release Si Ce from coating provided protection, NO3−release promoted localized phenomena scribe. This associated with preferential pitting at Cu-rich intermetallic compounds instead forming thick stableNO3−-rich passive layer.