Fabricating robust and repairable superhydrophobic surface on carbon steel by nanosecond laser texturing for corrosion protection

In recent years, fabricating superhydrophobic surface has been deemed to be a promising strategy for metal corrosion protection. Here, a facile and simple nanosecond laser texturing treatment was proposed for constructing superhydrophobic surface on carbon steel. During the machining process, a series of circle-shaped texture patterns with different p/d values were directly fabricated on steel surfaces by nanosecond laser machine. According to the SEM images, the circle-shaped texture pattern showed desirable multimodal structure. When the laser textured steel surface was further chemically modified, it became superhydrophobic. With increasing the p/d value from 1.0 to 1.8, the superhydrophobicity of laser textured superhydrophobic steels deceased continually due to the increased undesirable flat area. Furthermore, the laser textured superhydrophobic steel also showed superb mechanical durability against abrasive damage. Owing to the excellent obstructive effect to corrosive medium, all the superhydrophobic steels displayed superior corrosion resistance in 3.5 wt% NaCl solution and the superhydrophobic steels with lower p/d values displayed better corrosion resistance. In addition, the laser textured superhydrophobic steel also showed desirable chemical stability and excellent healability even it lost its superhydrophobicity. It was also worth pointing out that a relatively higher drying temperature could further improve the chemical stability and enhances the corrosion protection, which made this process technique more promising and competitive for future practical applications.