Fabrication of superhydrophobic, permeable, and anti-reflective porous steel surfaces using laser ablation and heat treatment

Abstract

Achieving high water resistance, good permeability, and anti-re ectivity on metal surfaces in a costeffective and e cient manner has always been a major challenge. This study addresses these challenges by utilizing laser ablation and heat treatment to achieve high water resistance, breathability, and anti-re ection properties in porous steel. The laser ablation and heat treatment process generated a unique porous nested structure on the surface and imparted excellent hydrophobicity and low adhesion properties on the porous steel surface. The size and density of the porous nested structure can be adjusted by changing the laser parameters. Notably, hydrophobicity of the surface is demonstrated to be closely related to the complexity of the surface microstructure, which follows the same trend as the permeability and anti-re ectivity. Speci cally, higher laser power and smaller laser spacing generate structures with greater aspect ratios and higher porosity, resulting in a rough surface with an increased air contact area and, consequently, an increase in the viscous permeability coe cient (B). Moreover, the intricate porous nested structure acts as a complex "light trap," whereby the re ectivity of the superhydrophobic porous steel surface ( laser power of 25.4 W and scanning interval of 100 µm) can be less than 15% across a wide wavelength range (200 nm-1800 nm). This study presents a method for fabricating multifunctional surfaces with superhydrophobicity, permeability and anti-re ectivity on permeable steel. The method provides an e cient and cost-effective solution to improve the performance of existing materials and has great potential for a wide range of applications such as solar cells, military stealth, and reduced navigation resistance.