One-Step Preparation of a Superhydrophobic Surface by Electric Discharge Machining with a Carbon Fiber Brush Electrode

Abstract

Superhydrophobic surfaces are extremely susceptible to damage, which can lead to a sharp decrease in their service life and physical properties. Therefore, developing methods to impart superhydrophobic surfaces with excellent wear resistance is crucial. In this article, a flexible carbon fiber brush was utilized as an electrode to fabricate micro-/nano-structures on a grooved surface via electric discharge machining in one step, resulting in a superhydrophobic coating with excellent wear resistance. Carbon fiber brushes exhibit several notable properties, including excellent flexibility, conductivity, and high temperature resistance. Carbon fiber brushes can adapt to the complex inner walls of grooves. Many nano-structures were fabricated on the grooves via pulse discharge, which resulted in a superhydrophobic surface with excellent wear resistance. The contact angle (CA) and sliding angle of the surface after discharge were 156.3 and 2°, respectively. The processed surface exhibits superior corrosion resistance compared to the stainless-steel substrate. The influence of the micro-groove shapes on wear resistance was tested. The results showed that, after 500 cm of wear, the shallow grooves retained their superhydrophobicity with a CA of 150.1°.

Investigation of the Influence of Machining Parameters and Surface Roughness on the Wettability of the Al6082 Surfaces Produced with WEDM

“…In cases of processes involving extremely high temperatures, such as EDM or laser machining processes, the wettability transition is reported to gradually occur due to the improved ability of the oxidized surface to adsorb and react with carbon. In both processes, the increase in the amount of carbon in the metallic surfaces is considered the key factor that induces the wettability transition [29,[60][61][62]. In the case of aluminum surfaces, the adsorption of carbon from carbon dioxide, carbon monoxide, and organic compounds found in the air has been proposed as the underlying mechanism of the hydrophobization of the surfaces [63].…”

“…The dual-scale morphology surfaces can give a rise to hydrophobicity [25]. Such hierarchical surface textures can be fabricated by utilizing a textured electrode in sink EDM [26,27], by applying a coating from the electrode to the surface during discharging [28,29] or by controlling the wire cut path in order to create various geometrical features with WEDM [30][31][32]. Applications of hydrophobic surfaces created with EDM and WEDM include improved heat transfer surfaces [33,34] anti-bacterial surfaces [35], anti-fouling surfaces [36,37], corrosion resistance surfaces [38], and surfaces for anisotropic wetting [39].…”

Coating-Free Superhydrophobic Hard Surfaces by Electric Discharge Machining with a Magnetic-Assisted Self-Assembly Sheet Electrode

“…Additionally, the mechanical stability of the substrate significantly improved after EDM. 37 Furthermore, Ouyang et al 38 prepared a superhydrophobic surface by EDM with a carbon fiber brush electrode. Undoubtedly, EDM holds tremendous potential for the fabrication of functional superhydrophobic surfaces on metal substrates.…”

Inducing hydrophobicity in Stainless Steel 304 by mechanical texturing and chemical functionalization

“…Surface topography can be achieved through various methods, such as wire Electric Discharge Machining [14][15][16][17][18], laser machining [14,19,20], photolithography [4,21] etc. Cao et al [14] and Wang et al [22] used wire EDM in order to introduce grooves on aluminum alloy and titanium alloy, respectively.…”