Nanosecond laser fabrication of superhydrophobic surface on 316L stainless steel and corrosion protection application

Herein, we developed an facile, cost-effective and efficient method to fabricate microstructures of different scales on 316 L stainless steel substrate surface by laser modification. By changing the laser parameters, such as various laser fluence (2.69, 3.96, 6.28, 8.14,9.55 J/cm2) during laser irradiation, different sizes of micro-cracks and brain-like microstructures can be obtained. The experimental results indicate that a static contact angle of 160 ± 5° and the sliding angle of 3 ± 0.5°, can be achieved at a scanning interval of 30.0 μm and laser fluence of 8.14 J/cm2, which has the best outstanding wettability. In addition, the microstructures and chemical compositions on the surface were examined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The corresponding corrosion resistance properties was evaluated by the means of potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The laser textured superhydrophobic surface was found to enhance the corrosion resistance dramatically. Also, after the laser modification, excellent self-cleaning performance was demonstrated based on tests with quartz sand particles. Particularly, we extensively discussed how the structures on the 316 L stainless steel were formed after the ultraviolet nanosecond laser irradiation and the interaction mechanism of the laser and substrate. This study not only provides important insights into the formation mechanism of laser textured surfaces, but also guides practical industrial applications as this approach is simple, low-cost and convenient for fabrication of large-area superhydrophobic surfaces on various metal materials.