Eco-Friendly Sol–Gel Coatings with Organic Corrosion Inhibitors for Lightweight AZ61 Alloy

The latest advances in technology and materials science have catalyzed a transformative shift towards the adoption of environmentally conscious and lightweight materials across key sectors such as aeronautics, biomedical, and automotive industries. Noteworthy among these innovations are the magnesium-aluminum (Mg-Al) alloys employed in aeronautical applications, contributing to the overall reduction in aircraft weight and subsequently diminishing fuel consumption and mitigating atmospheric emissions. The present work delves into a study of the anti-corrosive properties inherent in various sol-gel coatings, leveraging a range of environmentally friendly corrosion inhibitors, specifically tailored for samples of the AZ61 alloy. Methodologically, the work involves the synthesis and application of sol-gel coatings on AZ61 alloy containing eco-friendly inhibitors: L-cysteine, N-acetyl-cysteine, curcumin and methylene blue. Subsequently, an accelerated corrosion test in a simulated saline environment is performed. Through microstructural and compositional analyses, the best inhibitors responses are achieved with inhibitors containing S, N heteroatoms and conjugated double bonds in their structure, probably due to the creation of a continuous MgCl2 layer. This research contributes to the ongoing discourse on protective eco-coatings, aligning with the broader paradigm shift towards sustainable and lightweight materials in key industries.