Laser–Chemical Surface Treatment for Enhanced Anti-Corrosion and Antibacterial Properties of Magnesium Alloy

Magnesium (Mg) alloy with good biomechanical and biocompatible properties is considered to be a promising biodegradable material for various applications. However, Mg alloy that is chemically active tends to be corroded in a physiological environment. In this work, we proposed a laser–chemical surface treatment to combine laser surface structuring and stearic immersion treatment to enhance the anti-corrosion and antibacterial properties of Mg alloy. The effects of surface structuring, chemistry, and wettability were analyzed, and the performance of the proposed technique was evaluated in terms of corrosion resistance and antibacterial properties. The experiments showed the following: (1) surface structuring by laser-induced dual-scale micro/nanostructures produced superhydrophilicity, with a water contact angle (WCA) of 0° on the surface of the Mg alloy; (2) applying the stearic acid immersion changed the chemistry of the Mg alloy’s surface and thus facilitated the wettability transition to superhydrophobicity, with a WCA of 160.1° ± 0.5°; (3) the proposed laser–chemical surface treatment enhanced corrosion resistance and stabilized the wettability of Mg alloy in a corrosive medium significantly; and (4) the proposed laser–chemical surface treatment enhanced the antibacterial properties of the Mg alloy greatly, with an improved antibacterial rate as high as 82.05%. This work proved that the proposed laser–chemical surface treatment was a simple, effective, and efficient technique to modulate and control the wettability and further improve the anti-corrosion and antibacterial properties of the Mg alloy.