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