Construction and corrosion resistance of Ni-B4C superhydrophobic composite coatings on Q235 steel

Superhydrophobic coating technology is a promising anticorrosion method for metals. In this paper, a simple composite electrodeposition technique is proposed, in which micron-sized B 4 C particles are added to the electrolyte to construct Ni-B 4 C composite coating which exhibits a unique micro-nano structure. The addition of B 4 C particles promotes the construction of rough structure and enhances the corrosion resistance of the coating. When the B 4 C content is 3 g/L, the contact angle of the coating modified using a low surface energy material, reaches 162.5 ± 2°. The coating exhibits an excellent barrier effect against the corrosive medium. The superhydrophobic coating (M B-3 ) displays excellent corrosion resistance, and the corrosion protection efficiency reaches 99.53% in 3.5 wt% NaCl solution. The corrosion current density of M B-3 is 7.95 × 10 −8  A/cm 2 , which is three orders of magnitude lower than that of the pure Ni coating (M B-0 ). The addition of B 4 C promotes the growth of the coating, resulting in excellent shielding and stability.