Enhanced properties of dual-scale bionic superhydrophobic surface on Ti-6Al-4V fabricated via laser powder bed fusion

Abstract

The mushroom-like macrostructure array effectively anchors the liquid at the air-liquid interface, thereby enhancing the corrosion resistance and anti-icing properties of superhydrophobic surfaces. However, fabricating such structures on metal surfaces remains a challenge with conventional techniques. To address this, laser powder bed fusion (LPBF) was employed to fabricate a mushroom-like macrostructure array on Ti-6Al-4V, enabling the simultaneous fabrication of both the substrate and the array. Following electrochemical polishing, hydrothermal synthesis, and chemical modification, a dual-scale bionic superhydrophobic surface was developed. The combination of the mushroom-like macrostructure array, flower-like TiO₂ particles, and fluorine-containing functional groups plays a crucial role in enhancing wettability control. Consequently, the surface achieves a water contact angle (WCA) exceeding 155° and exhibits aerophilicity underwater, allowing it to remain dry even when fully immersed. A systematic performance analysis demonstrated notable improvements in corrosion resistance, anti-icing performance, and durability. The corrosion current density decreased from 6.53 μA/cm² to 0.67 μA/cm², an order of magnitude decrease compared to the Ti-6Al-4V plate. At −15 °C, the surface significantly extended droplet freezing time and suppressed frost formation. Moreover, the surface maintained a WCA above 155° after 72 h of immersion in a 3.5 wt% NaCl solution and retained hydrophobicity even after 2000 mm of wear on 800# SiC sandpaper. This LPBF-based approach offers a scalable and durable strategy for fabricating metallic superhydrophobic surfaces.