Enhanced corrosion resistance and self-cleaning of AlSi7Mg0.3 via superhydrophobic surface using laser structuring and stearic acid grafting

The study developed a superhydrophobic surface treatment for the cast aluminium alloy AlSi7Mg0.3 to improve corrosion resistance and self-cleaning abilities. The treatment was based on laser surface structuring and grafting of a saturated fatty acid, representing a fast, facile and environmentally friendly approach. The effects of different laser structuring parameters (scanning line spacings of 40 μm, 70 μm, or 100 μm) on surface roughness were studied alongside the subsequent surface modification via stearic acid grafting. Surface topography and wettability were assessed using a contact profilometer, scanning electron microscopy, and a goniometer. Corrosion resistance was evaluated through electrochemical testing, while self-cleaning properties and droplet bouncing were also examined. The results demonstrated that the superhydrophobic surface produced with optimised laser structuring parameter (line space 70 μm) and stearic acid modification exhibited superior corrosion resistance compared to the solely laser-structured aluminium. Additionally, these surfaces exhibited effective self-cleaning and water-repellent properties. Such an approach to imparting superhydrophobic surface properties on AlSi7Mg0.3 is straightforward, cost-effective, and industrially viable, making it suitable for applications requiring better corrosion protection and a clean surface.