Effect of Nanosecond Laser Machining and Heat-Treatment on Wettability of Pure Aluminum Surface

The micro-nano structure was prepared on the surface of pure aluminum plate by nanosecond laser machining technique, and then was heat-treated at 150 ℃ for 2 h. The effect of laser scanning interval (0.005-0.020 mm), scanning speed (100 -1 700 mm·s^-1) and heat treatment on the wettability of the pure aluminum plate surface after laser ablation was studied. The results show that the regular micro-nano grid structure was formed on the surface of pure aluminum plate after laser ablation with different process parameters. The pure aluminum plate surface after laser ablation was super hydrophilic, and after heat treatment changed to be hydrophobic or even super-hydrophobic. With increasing scanning speed and scanning interval, the contact angle of pure aluminum plate surface after laser ablation and heat treatment changed little, and the sliding angle increased; the surface showed different degrees of wettability. After laser ablation with laser scanning speed of 100 mm·s^-1 and scanning interval of 0.005 mm and heat treatment, the pure aluminum plate surface had dense micro-nano structure, and the best super-hydrophobicity with contact angle of 155.6° and sliding angle of 4°.