Design of polymeric core-shell nanocontainers impregnated with benzotriazole for active corrosion protection of galvanized steel

Abstract

Abstract Polymeric nanocontainers (NCs) impregnated with corrosion inhibitor benzotriazole are formed using layer-by-layer deposition of poly(acrylic acid) and poly(diallyldimethylammonium chloride) onto hematite particles in the presence of 0.1 M NaCl. Electric light scattering and electrophoresis are employed to control the formation and the size of NCs, as well as the stability of their suspensions. The inhibitor loaded NCs are incorporated into the volume of the galvanized coating during the electrodeposition of zinc on the steel substrate to ensure additional self-healing effect in the case of corrosion attack. The surface morphology and the uniformity of this composite coating as well as the lack of aggregation of the nanocontainers is demonstrated by scanning electron microscopy. The influence of NCs present in the zinc electrolyte on the cathodic and anodic processes is investigated by cyclic voltammetry. The corrosion behavior of the composite coatings at conditions of external cathodic and anodic polarization is tested with potentiodynamic measurements and the results are compared to pure zinc coatings. The composite coatings with embedded NCs revealed enhanced corrosion protection of low carbon steel in comparison with the pure zinc coatings in neutral corrosion medium.