Robust nickel-reduced graphene oxide-myristic acid superhydrophobic coating on carbon steel using electrochemical codeposition and its corrosion resistance

We report a facile approach to fabricate superhydrophobic (SHP) coating of nickel (Ni)-reduced graphene oxide (rGO)-myristic acid on carbon steel (CS) surface with superior corrosion resistance and self-cleaning ability, using electro-codeposition. The electro-deposition current density and electrolyte bath temperature are optimized to obtain the desired hierarchical surface textures with very high water contact angle (WCA). The microstructure, chemical compositions, surface roughness, and self-cleaning properties were examined using FESEM, XRD, XPS, EDX, AFM, water bouncing etc. A WCA of 174 +/- 1.5 degrees, with a sliding angle (SA) of similar to 1 degrees, was obtained at 60 mA.cm(-2) and 45 degrees C. The FESEM surface morphology showed a hierarchical pinecone structured Ni-rGO composite film. The good adhesion and mechanical stability of SHP coating is achieved by phosphating the surface prior to deposition. The SHP surface showed a two order reduction in the corrosion current density and similar to 3 orders higher impedance, as compared to uncoated surface. This study demonstrates a new approach for fabricating mechanically and chemically durable SHP coating on CS specimens.