Silica-Based Coatings for Corrosion Protection of AA7075 Aluminum Alloy
Materials Performance and Characterization
The large economic and environmental impact caused by corrosion of metal structures has demanded new types of anti-corrosion coatings. This study proposes the application of silica-based coatings for corrosion protection of AA7075 aluminum alloy in saline environments rich in chloride ions. These coatings were obtained using the sol-gel technique. The samples were dip-coated in two types of solutions: (a) a mix of tetraethyl orthosilicate (TEOS) with 3-(Trimethoxysilyl)propyl methacrylate (TMPM) (Coating 1); and (b) a mix of titanium (IV) isopropoxide (TIP) with TMPM (Coating 2). The cure temperatures of the coatings were of 25°C, 60°C, 100°C, and 130°C, with treatment times of 1 and 3 hours. Characterization of the coatings was done by potentiodynamic polarization in aqueous saline solution (sodium chloride 3.5 %), nanoscratching, and scanning electron microscopy (SEM). The layers produced were uniform with good scratch resistance and with superior corrosion resistance when compared to the substrate.
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Rêgo, G., Bandeira, R., Aureliano, R., Lombardi, A., Casteletti, L., and Totten, G., "Silica-Based Coatings for Corrosion Protection of AA7075 Aluminum Alloy," Materials Performance and Characterization, Vol. 6, No. 5, 2017, pp. 904-912.