On the Development of an Intelligent Poly(aniline-co-o-toluidine)/Fe3O4/Alkyd Coating for Corrosion Protection in Carbon Steel

The corrosion of metals and alloys presents a significant challenge in many industries, demanding constant maintenance, and thereby increasing costs. In response to this problem, the smart corrosion protection coating has emerged as a promising solution. By enabling the immediate detection of, and response to, environmental changes, such as in the temperature and pH, these smart coatings contribute significantly to extending a material’s lifespan, and reducing maintenance expenses. In this study, nanomagnetic [poly(aniline-co-o-toluidine)/Fe3O4] systems were prepared and used as a self-healing corrosion inhibitor, mixed with alkyd paint at different weight percentages (5–25%). The composites were used as a coating on carbon steel (C1010), and their corrosion protection performance was tested in 0.1 mol/L HCl, using electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and FTIR analyses. The results showed an adequate corrosion inhibition performance for the developed composites, compared to the alkyd paint alone, reaching an inhibition efficiency of 80% at 20 wt.% of composite. Adding increasing weight percentages of the developed composites to the paints led to a significant increase in the corrosion resistance, accompanied by a remarkable decrease in the double-layer capacitance. Thus, these developed composites show excellent potential as a corrosion protection formulation in paints.