AA2024-T3 are widely used in various applications because of their exceptional physical properties. However, they are susceptible to corrosion and cavitation erosion in aggressive environments due to high concentration of copper. Sol-gel coatings in the field of corrosion prevention are emerging. Improved thickness of coatings significantly improves the barrier effect of the coatings, thereby improving their operational-life in industrial applications. To date, a limited amount of work has been carried out in determining the effect of hybrid sol-gel coatings on abrasion and cavitation erosion of AA2024-T3. The present study investigates the effect of thickness of the coatings on morphology, corrosion, abrasion and cavitation erosion properties of the prepared hybrid sol-gel coatings deposited on AA2024-T3 surfaces. The hybrid sol-gels have been synthesized from 3-trimethoxysilylpropylmethacrylate (MAPTMS), and a zirconium complex prepared from the chelation of zirconium n-propoxide (ZPO), and methacrylic acid (MAAH). AA-2024 T3 were coated using single-dip, double-dip and triple-dip. Abrasion and cavitation erosion tests were performed according to the relevant standards. Structural damage caused by corrosion, abrasion and cavitation erosion was studied by Optical Microscope and Scanning Electron Microscope (SEM). Corrosion protection performance of the coatings was tested using Open Circuit Potential (OCP) and Potentiodynamic polarization (PDS). Results indicated that the multilayer coated samples improved the corrosion, cavitation erosion and abrasion resistance of AA2024-T3. Hence, the prepared silica-based coatings can be proposed as a potential choice for marine renewable energy applications.

Sol–gel coatings can provide anti-fouling and erosion resistance while being safe to use in the marine environment. MAPTMS/ZPO multilayer coatings deposited on the AA2024-T3 aluminium surface using the dip-coating method at three different thicknesses (2, 4, and 6 µm) are investigated in this work. The coatings are characterised in terms of physical and mechanical properties, and these properties are investigated in comparison to previously obtained cavitation erosion resistance levels of the coatings. Additionally, the efficiency of the coatings against biofouling was assessed using Phaeodactylum tricornutum, a marine diatom. The influence of the formation of organic–inorganic hybrid materials (OIHMs) from the prepared sols on the physical and mechanical properties of the coatings were analysed. A variety of techniques, including attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), water contact angle (WCA) measurements, pencil hardness testing, cross-cut adhesion testing, a roughness profilometer, and nano-indentation, were performed on the bare and coated substrates. The results indicated that the thickness, hydrophobicity, and adherence of the coatings are strongly affected by the roughness. The elastic strain failure (H/E) and resistance to plastic deformation (H³/E²) coefficients were higher than those of the bare substrate before and after the cavitation erosion test, indicating that the coating had a higher ability to withstand deformation in comparison to the substrate alone. Furthermore, the microscopic analysis of a marine diatom, Phaeodactylum tricornutum, revealed that coated surfaces exhibited a decreased rate of bacterial adhesion and biofilm formation. The data show that sol–gel formed coatings outperform uncoated AA2024-T3 in terms of hardness, elastic strain, plastic deformation, and biofouling resistance. These characteristics are attributed to the coatings’ mechanical and adhesive capabilities, as well as their tribological behaviour.