(511b) Corrosion Protection of Aluminum Alloy Via Graphene-Polymer Nanocomposite Coatings

As hexavalent chromium (VI) is phased out of use as a corrosion inhibitor, the search for environmentally friendly non-toxic anticorrosion approaches continues. Here, we present graphene-polymer nanocomposite protective coatings made using a simple airbrushing technique. The nanocoating can be deposited over large areas onto a variety of surfaces from stock solutions of polymer and graphene oxide sheets, followed by chemical reduction. Sprayed onto aluminum alloy (AA) 2024-T3, the coatings bear a brick-and-mortar structure, in which graphene sheets lie parallel to the surfaces in a densely packed structure. The end result is pinhole-free multilayered composite coatings with improved barrier properties. The graphene sheets act as a physical barrier to oxygen diffusion, thus hindering the corrosion cycle. First, we present the spraying process, and what parameters contribute to making a pin-hole free nanocoating on a metal surface. Second, we present the final structure of the film and its physical properties. Lastly, we explore the suitability of this coating towards corrosion protection is evaluated using electrochemical impedance spectroscopy under varying salt conditions.