Development of corrosion-resistant superhydrophobic coating on brass using modified silica nanoparticles

In this study, SiO2 nanoparticles were modified using triethoxyoctylsilane to fabricate a corrosion-resistant superhydrophobic coating on brass. The brass substrate of 1 x 1 cm(2) was cut from the bulk using an electrical discharge machine (EDM) that generated a micro-pattern on its surface then it was chemically etched with Piranha solution. In order to create nano roughness on the etched micro-patterned brass substrate and to reduce its surface energy, surface-modified SiO2 nanoparticles were coated on the brass using the solution-immersion approach followed by annealing. AFM and FESEM analysis of the coated brass showed the presence of SiO2 nanoparticles and their clusters leading to the superhydrophobicity. The coated brass exhibited a maximum water contact angle (CA) of 152 degrees +/- 2 degrees and a sliding angle (SA) of 7 degrees +/- 3 degrees. The electrochemical impedance spectroscopy (EIS) plots demonstrated a high impedance value for coated brass compared to uncoated brass. Conversely, the corrosion current density (I-corr) of coated brass (0.068 x 10(-6 )A cm(2)) is much lower than the uncoated brass (0.369 x 10(-6) A cm(2)) signifying efficient corrosion resistance of the coated brass. The present work has inordinate potential to control the corrosion of metals in corrosive conditions.[Graphical Abstract]