Investigation of the anti-corrosion performance of a Cu/Ni-B4C superhydrophobic coating with self-cleaning and abrasion resistance properties

A Cu/Ni-B4C superhydrophobic coating was fabricated on the surface of Q235 steel under different current density via electrodeposition. The distribution of electric field influenced by current density controls the growth of rough structure. Therefore, the effect of current density was measured by the morphology and wettability of coating and analyzed by Electric field distribution model. The coating surface demonstrates the most uniform and compact rough structure at a current density of 3 A/dm2 (MC-3) obtaining contact angle 160 +/- 2 degrees after the surface energy reduced by stearic acid. The self-cleaning performance and mechanical stability of MC-3 coating were studied. The potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) were used to measure the anti-corrosion and protection performance of the coatings with different morphology and contact angle. The protective performance of MC-3 coating soaked in 3.5 wt% NaCl solution for different time was studied by EIS. The wetting stability of different coatings was studied by single frequency impedance spectroscopy. Then the double protective mechanism of superhydrophobic coating was described and the corresponding model was established.