The Influence of Sample Preparation Techniques on Aluminium Alloy AA2024-T3 Substrates for Sol-Gel Coating

Sol-gel coatings provide environmentally friendly surface protection for metals and can replace toxic pre-treatments such as those based on hexavalent chromium on metal alloys. This project ultimately aims to develop silica-based organic–inorganic sol-gel derived thin film coatings possessing anti-corrosion and anti-fouling properties on aluminium alloy substrates. As with any coating, sample preparation plays a significant role in the performance of a sol-gel coating. Therefore, it was necessary to define a preparation method that combines the removal of contaminants and surface roughening to improve adhesion and reproducibility. Four techniques were investigated: fine abrasive sandpaper cleaning, acetone degreasing only and cleaning with an industrial-available alkaline cleaner for 5 min and 30 min.