Frost Resistance of Superhydrophobic TC4 Titanium Alloy Surface byNanosecond Laser

The surface of TC4 titanium alloy was etched by nanosecond laser, and then baked in an electrothermal drying oven. The wetting characteristics, microstructure and frost resistance of titanium alloy surface were studied. The results show that after nanosecond laser etching at 100 W laser power and baking, the contact angle of titanium alloy surface exceeded 160°, and the rolling angle was less than 5°, indicating the surface had superhydrophobic properties. The surface of titanium alloy presented nano pits, bulges and regular spherical structures. After baking, the surface of laser etched titanium alloy met the conditions of rough microstructure and low surface energy, and the wetting characteristics of the surface changed from superhydrophilic state to superhydrophobic state. The time required for complete freezing of 9 μL water droplet on superhydrophobic titanium alloy surface at -15℃ was 360 s, which was more than 2 times longer than that of titanium alloy without laser etching, and the contact angle of water droplets could still be maintained greater than 130° after complete freezing. After being frozen for 10 min at -15℃ with constant humidity, only scattered small frost crystals appeared on the superhydrophobic titanium alloy surface, while a large number of small frost crystals were densely distributed on the surface of titanium alloy without laser etching.