The advantageous properties of steel result in it being in high demand for structural applications. Unfortunately, it does have some limitations, such as vulnerability towards corrosion and, depending on the service conditions, microbiologically influenced corrosion (MIC). A simple strategy for protecting steel from such detrimental environments is through the incorporation of corrosion inhibitors into the coating system that can combat both corrosion and the microbial attachment that exacerbates the degradation.
This work examines the effectiveness of combining a proven corrosion inhibitor for steel, lanthanum 4-hydroxy cinnamate (La(4OHCin)3), with a candidate microbial inhibitor into a polyurethane-based coating to stifle corrosion of mild steel AS1020.
Artificial defects have been made on each sample and exposed to a high humidity environment to induce corrosion attack. The coatings are visually compared and subsequently characterized with methods such as SEM/EDS. Of the materials tested, La(4OHCin)3 demonstrated significant inhibition of corrosion at the defect site while not degrading the polyurethane coating.