Fabrication of superhydrophobic aluminium alloy surface by twice nanosecond laser scanning

The superhydrophobic surface of aluminium alloy was fabricated by nanosecond laser facility. The surface structures of the specimen were observed by scanning electron microscope and confocal laser scanning microscope. Surface hydrophobicity was evaluated by contact angle of deionised water. The phases present in the aluminium alloy surface were identified by X-ray energy spectrum analysis module of scanning electron microscope. The study showed that, a simple method of the fabrication of superhydrophobic aluminium alloy surface by twice nanosecond laser scanning, can make bowl like micro-nano structure on the surface of specimen. Compared with the contact angle of 140.21 degrees, which of sample surface with groove structure obtained by using once nanosecond laser scanning, the contact angle of the sample surface prepared by twice nanosecond laser scanning can up to 154.36 degrees. On the as-obtained sample surface, there is the hydrophobic substance containing more oxygen element, because of the coupling effect of laser and material. The surface roughness is related to the depth of the microstructure, and has no clear relationship with the surface wettability. Therefore, it is speculated that the joint action micro-nano structure and hydrophobic elements made the surface of aluminium alloy show super hydrophobicity.