Enhanced adhesion and corrosion resistance of reduced graphene oxide coated-steel with iron oxide nanoparticles

Abstract

Despite its potential for use in coating applications, graphene can promote corrosion at exposed graphene-metal interfaces because it presents cathodic properties when exposed to most metals. Moreover, such exposed areas can accelerate localized corrosion, which may lead to serious damage of the coated metal. This study describes a method for preparing reduced graphene oxide (RGO) coatings with iron oxide nanoparticles (Fex−1Ox), which exhibit improved adhesion strength and oxidation resistance on steel substrates. A suspension that contained a mixture of graphene oxide (GO) and graphene oxide with Fex−1Ox (GO/Fex−1Ox) was formulated and applied to a large area on a steel substrate using electrophoretic deposition. Mechanical and electrochemical characterizations of the RGO and RGO/Fex−1Ox coatings were conducted after thermal reduction at 810 °C in a 10 % Ar/H2 atmosphere. A 138 % improvement in adhesion tensile strength was measured using a mechanical test derived from the standard pull-out test. Moreover, the enhanced oxidation resistances of RGO and RGO/Fex−1Ox coatings were confirmed after thermal reduction using electrochemical impedance spectroscopy and the potentiodynamic polarization method. From calculation of corrosion rate, RGO/Fex−1Ox coatings were corroded by 4 and 13 times slower than RGO coatings and bare steel, respectively. These results suggest that graphene coatings with iron oxide nanoparticles could serve as effective adhesion-promoting intermediary layers that retard steel corrosion in certain applications.