Fabrication of a Robust Superhydrophobic Ni Coating with Micro–Nano Dual-Scale Structures on 316L Stainless Steel

Herein, a superhydrophobic Ni coating is prepared on 316L stainless steel by electrodeposition and low energy modification with tetradecanoic acid. After 20 min of electrodeposition with a current density of 8 A dm −2 , a Ni coating with micro–nano dual-scale structures is obtained. The coating becomes superhydrophobic with a water contact angle (WCA) of 160.4° and a sliding angle (SA) of 8.3° after being immersed in the tetradecanoic acid solution (5 g L −1 , 12 h). A two-level structure model is established for explaining the effect of morphology on the wettability of the coating. The WCA value of the superhydrophobic Ni coating retains above 150° after being exposed in outdoor environment for 6 months and in flowing environment for 7 days. In addition, the coating still shows superhydrophobicity after 9 times of mechanical abrasion test, 12 h of acid soaking (pH = 1), and 16 h of heat treatment in 200 °C. Moreover, the coating improves the corrosion resistance of the steel substrate. This superhydrophobic Ni coating provides a simple method to prevent stainless steel from corrosion. And the theoretical calculation of the two-level model can provide an innovative strategy for designing the structure of the superhydrophobic coating.