Corrosion Resistance of Anodized and Composite‐Coated Aluminum Alloys: A Comprehensive Review on 5xxx and 6xxx Series

The corrosion resistance of anodized and composite‐coated aluminum alloys is rigorously examined in this review with an emphasis on the 5xxx and 6xxx series, which are extensively utilized in the transportation and structural industries. The study starts with a historical review of corrosion prevention before delving into the development and fundamental ideas of anodization and describing the impact of important operational factors, such as alloy composition, post‐treatment techniques, anodization time, and current density. The cutting‐edge techniques, such as multistep anodization and plasma electrolytic oxidation (PEO), improve the oxide layer, enhancing corrosion potentials augmented by +200 to +400 mV, and impedance values exceeding 10 6 Ω·cm 2 . In addition, a critical review is conducted on how different electrolytes and their concentrations can be used to customize corrosion performance. When combined with anodized substrates, composite coatings, an emerging class of surface protection, are evaluated for their synergistic activity. Composite coatings that integrate graphene, MXenes, and h‐BN significantly improve barrier efficacy, achieving corrosion inhibition efficiencies up to 99% and ensuring an enhancement in adhesion strength by 30%–40%. The study highlights important obstacles to developing long‐lasting, eco‐friendly, and alloy‐specific protection techniques. A forward‐looking viewpoint highlights the need for multifunctional coatings, complex characterization, and predictive modeling, which are being investigated to optimize performance in real‐world situations.