Laser belt processed micropillars with microporous structure and nanoparticles to control the surface wettability of superhydrophobic Inconel 718 alloy

Abstract

The superhydrophobic surface features such as self-cleaning, keeping dry and low adhesion have wide application prospects in biotechnology, medicine, and engineering. As a superhydrophobic surface machining method, pulsed laser ablation has attracted wide attention due to its high precision. However, due to the efficiency, pulsed laser composite processing technology has gradually developed into the main preparation method for superhydrophobic surfaces. A effective machining method (laser belt collaborative processing) for superhydrophobic surface preparation was proposed in this paper. The microgroove surface could be prepared by using a pyramid abrasive belt with regular consistency of abrasive height and a high precision picosecond laser. After rotating the workpiece 90°, the micropillar surface could be formed by machining again. The height of micropillars increases significantly with the increase of the laser power. There are multiscale structures on the micropillar surface, including micropores, microaggregates, and nanoparticles. With the design spacing of the micropillar increasing to 80 μm, the contact angle reaches a maximum value of 153.8° The adsorption of carbon elements and the low solid-liquid contact fraction are beneficial to the enhancement of surface hydrophobicity. The superhydrophobic micropillar surface is extremely stable, which can withstand various harsh treatments/environments, such as sandpaper abrasion, tape peeling. A new processing method for superhydrophobic micropillar surface preparation was proved, which is conducive to the application of superhydrophobic surfaces.