Direct cerium-doped hybrid sol-gel sealing of TSA-anodized AA2024-T3 for corrosion protection

The corrosion protection performance of the AA2024-T3 alloy, anodized in a tartaric‑sulfuric acid medium and subsequently sealed with a hybrid sol–gel coating, was evaluated with and without the incorporation of Ce 3+ species into the hydrolysis solution. Structural and surface analyses confirmed that the presence of cerium contributed to the formation of thicker, more compact, and hydrophobic coatings. Electrochemical impedance spectroscopy demonstrated that the Ce-modified films significantly increased the system's durability, extending the time to failure by approximately 2.5 times compared to the Ce-free counterparts. Local electrochemical impedance spectroscopy was used to explore potential self-healing responses; however, the results were inconclusive, likely due to the gradual leaching of the inhibitor species over time. Despite this, the strategy of Ce incorporation into the sol-gel network proved to be effective in enhancing long-term barrier properties.