Electron Donor-Induced Electrochemical Reduction in Vanadate Anions to Enhance the Electrochemical Performance of Plasma Electrolytic Oxidation Layers

Despite the increasing interest in enhancing the electrochemical stability of Al alloys through protective coatings, the role of electron donor agents during coating formation remains poorly understood in terms of morphological control and anticorrosion properties in aqueous environments. In this context, 1H-Benzotriazole (BTA) was utilized as a proof of concept to regulate the in situ reactive integration of V2O5 into the alumina layer via the plasma electrolytic oxidation of a 6061 Al alloy. BTA played a crucial role in chemically incorporating V2O5 into the alumina coating by supplying electrons to VO3− ions, facilitating their reduction. The quantity of BTA added to the electrolyte was found to influence defect morphology and concurrently enhance the chemical incorporation of V2O5. Notably, corrosion measurements revealed that the less porous hybrid film formed with higher corrosion resistance was associated with the utilization of increased concentrations of BTA. These findings highlight the potential of BTA in modifying the structure and improving the ability of alumina coatings to resist corrosion, enabling advanced applications in protecting Al alloys from corrosion.