Modification of aluminum 1050 and 2219 alloys using CuBr nanosecond laser for hydrophobic and hydrophilic properties.

This study investigates the use of CuBr vapor nanosecond laser with combined 510 nm and 578.2 nm wavelengths for surface treatment of 1050 aluminum and 2219 aluminum alloys. Laser-induced periodic surface structuring (LIPSS) was used to optimize processing parameters to achieve hydrophobic and hydrophilic properties on the surface. The wetting properties were measured and the roughness results (Ra, Rz, Rq) evaluated. Prior to and after laser treatment, surface wetting and roughness changes were investigated. The wetting study showed that the maximum contact angle between a droplet of deionized water and the treated surface can be reached between more than 140 degrees and less than 10 degrees, which, respectively, is a super hydrophobic and hydrophilic surface. Compared to untreated surface, wetting increased by more than 2 times and decreased more than 8 times. Overall, experiments show the dependence of wetting properties on laser input parameters such as scan speed, scan line distance with different delivered energy amounts. This study demonstrates the possibility of laser parameter optimization which do not require auxiliary gases and additional processing of the resulting surfaces to obtain different wetting properties on the surface. The findings described in this article suggest that this surface treatment method is a promising method for industrial applications where surfaces with special wetting and roughness properties are required, as an example of laser marking of serial number of parts used in wet environments such as aerospace, shipbuilding and defense industries.