Fabrication and droplet impact performance of superhydrophobic Ti6Al4V surface by laser induced plasma micro-machining

Abstract

Titanium alloy Ti6Al4V super-hydrophobic surface plays a key role in enhancing the water repellency and anti-condensation of the fuselage. In this study, laser-induced plasma micromachining (LIPMM) is used for processing an array of cone-shaped protrusions on the surface with a micro-nano hierarchical structure. The relationship between surface wettability, micro-nano structure, and surface chemical composition was studied, meanwhile, the droplet impact behavior was experimented and simulated. The study found that with the aging treatment surface C element distribution and content increased significantly, and the wettability changed from superhydrophilic to hydrophobic. As the scan line spacing (50, 40, 30 μm) decreases, the contact angle increased and the hysteresis contact angle decreased. At 50 times and 30 μm line spacing, the contact angle 151.209°>150°, and the hysteresis contact angle 2.619°<10°. The collision experiments reveal that with the increase of the collision velocity (0.44 m/s to 0.98 m/s), the spreading diameter and the rebound height increases. The comparative results of experiments and simulations of collisions present that as the contact angle increases, the spreading diameter decreases, and the rebound height increases. Therefore, the LIPMM is feasible for the fabrication of a superhydrophobic surface and has a wide range of application prospects such as waterproofing, anti-fouling, and anti-icing.