A new one-step approach for the fabrication of microgrooves on Inconel 718 surface with microporous structure and nanoparticles having ultrahigh adhesion and anisotropic wettability: Laser belt processing

Abstract

Two typical aspects of wettability on functional surfaces, namely, ultrahigh adhesion and anisotropic wettability, have attracted considerable interest for practical applications. A new and efficient method, laser belt processing, was proposed in this study for the preparation of Inconel 718 surfaces with ultrahigh adhesion and anisotropic wettability. The microgroove depth processed by the laser belt could be increased without changing the processing parameters, and microporous structures with nanoparticles were introduced. The results showed that the width and depth of the microgrooves increased with increasing laser power and processing times, whereas the depth decreased when the processing times was increased by eight times owing to the removal effect of belt grinding. The surface wetting state was between the Wenzel and Cassie wetting states, and van der Waals forces on the surface provided ultrahigh adhesion. The anisotropic wettability increased with increasing laser power, with a maximum contact angle of 121.3° and anisotropy of 34.9° at a laser power of 9.8 W. The microporous structure with nanoparticles enhanced the anisotropy. A new approach for the preparation of microgrooves was thus demonstrated. The prepared surface with ultrahigh adhesion and anisotropic wettability has promising applications in the field of droplet smart transport and microfluidic devices.