A contrastive investigation on anticorrosive performance of laser-induced super-hydrophobic and oil-infused slippery coatings

Nature inspired super-hydrophobic surface has aroused extensive attention on corrosion prevention. More works have investigated the instant corrosion resistance of fresh super-hydrophobic surface, but less research focused on its stability when immersed into corrosive solution for long time. Recently, another bio-mimic surface with slippery coating also presented great corrosion inhibition due to its excellent insulation between the corrosive medium and base material. However, which coating is suitable for long-term immersion into corrosive environments still remains to investigate. Herein, we firstly fabricated a super-hydrophobic coating on 316 L stainless steel by nanosecond laser ablation combining fluoroalkylsilane modification. Then a slippery coating was obtained by further infusing silicon oil into the as-prepared super-hydrophobic substrate. The PDP and EIS measurements indicate that both fresh super-hydrophobic and slippery surface were observed to improve the corrosion inhibition for the base substrate, and the performance of slippery surface was superior to that of superhydrophobic surface. Immersion experiments infer that the air cushion of the super-hydrophobic surface was easily destroyed, resulting in a rapid failure of super-hydrophobicity and instability of corrosion resistance. In contrast, after immersed into 3.5 wt.% NaCl solution, the wetting property of oil-impregnated slippery surface almost remained the same. In addition, the electrochemical measurements reveal that the slippery coating presented exceptional anticorrosion behavior after long-term immersion into corrosive liquid. Therefore, the authors believe this study is expected to promote the development of anticorrosive coating for the steel materials. This work is of great importance for employing laser ablation to fabricate slippery surface, which is convenient and effective for metallic corrosion prevention in industrial fields.