Evaluation of silane-doped epoxy coatings for resisting aluminum corrosion by oxalic acid, an A. Niger metabolite

The goal of this study was to investigate whether silane-doped epoxy coatings are capable of preventing corrosion of aluminum alloy 2024-T3 by oxalic acid, one of the primary metabolites of the fungus Aspergillus Niger. Previous research suggested the success of these types of coatings at preventing AA 2024-T3 corrosion in saline solutions, and this study was meant to build on those findings by investigating the efficacy of the coating in an acidic environment. Each coating was applied to an AA 2024-T3 coupon by dissolving the epoxy and varying amounts of 3-aminopropyltriethoxysilane in acetone and then dripping the solution onto the surface. After allowing the coating to dry and cure, the coupons were weighed, and then immersed in oxalic acid solution for 7 days. Two different independent variables were investigated – the silane weight percentage in the coating (0 wt%, 5 wt%, 10 wt%, 20 wt%) and the pH of the oxalic acid solution used in the immersion tests (pH = 1.16, 2, 3, 4, 11). After analyzing the results, no strong conclusion can be made regarding the proposed hypotheses, as too much variance exists within the data. However, due to significant pitting corrosion observed across all samples, a general conclusion can be made that this coating does not offer adequate corrosion protection in this particular environment