Superhydrophobic aluminum surfaces with nano-micro hierarchical composite structures: A novel and sustainable approach to corrosion protection

Abstract

The unique properties of aluminum (Al) and its alloys make Al one of the most versatile, economical, and widely-used materials in various industries. However, the corrosion and leaching of Al can cause significant issues for the lifetimes of mechanical structures and machine components as well as environment and health problems. In the present study, a simple, eco-friendly, and rapid fabrication of superhydrophobic Al surfaces was introduced. The superhydrophobic Al surfaces with hierarchical composite structures combining microstructures prepared by laser texturing, the new formation of pseudo-boehmite nanostructures prepared by boiling water treatment, and low surface energy prepared by silicone oil heat treatment showed excellent corrosion resistance. The mechanism for wettability change and anti-corrosion were analyzed. The influence of laser parameters and surface modification procedures on the wettability and corrosion resistance of Al surfaces was also analyzed systematically through a series of surface characterization techniques, potentiodynamic polarization tests, and electrochemical impedance spectroscopy tests. The corrosion protection efficiency of the fabricated superhydrophobic Al surface has reached up to 99.40 % as compared with an untreated flat surface. Furthermore, the fabricated superhydrophobic surfaces show good stability even after prolonged exposure to air, fresh water, seawater, and high temperature environments. The performance of the non-wetting surfaces is demonstrated through self-cleaning, water jetting, and water droplet bouncing phenomena. This research provides a novel and sustainable approach for superhydrophobic metal surfaces and improved corrosion resistance for potential practical applications.