Fabricating Superhydrophobic Protective Films with Enhanced Self‐Cleaning and Anti‐Corrosion Properties through Multiple Anodic Oxidations on Aluminum Alloys

Abstract

The development of aluminum (Al) alloys with superb anticorrosion and self-cleaning properties for prolonging the working life and reducing maintenance cost is a hot topic of concern. Since anodic oxidation has been proven to be an effective technique to prepare micro or nanostructures on Al alloys surface, this study proposes a novel and scalable multiple anodic oxidations method with gradient current densities for fabricating hierarchical micro-nanostructure film with appropriate roughness on Al alloys, while the SiO 2 -silane film reduced the surface free energy and enhanced the surface chemical inert state. As expected, the surface of Al alloys modified with the multiple anodic oxidations and SiO 2 -silane film has the most substantial hydrophobic properties, with contact angle up to 166°, rolling angle as low as 3.17°and excellent nonsticking effect of water droplets. This method enables the Al alloys surface to have excellent self-cleaning performance and corrosion resistance with protection efficiency up to 98.81 %. This multiple anodic oxidations method has a wide range of references for the modulation of micro-nanostructure on Al alloys surface and other metallic substrates to assemble superhydrophobic protective films.

Facile Fabrication of High‐White and Robust Superhydrophobic Ni/Al2O3 Composite Coating on Al Alloy

“…To obtain essential components in superhydrophobicity, namely, roughness and low adhesion to water, various surface modification technologies and methods have been developed, such as electrodeposition, electrospinning, spraying, chemical vapor deposition, and immersion coating. [24][25][26][27][28] Recently, it has been reported that Qi et al proposed an advanced method, they prepared micro/nanostructures and surface layers enriched with organic groups through nonsolvent-induced phase separation method for preparing superhydrophobic surfaces. [29] Wang et al compared different pretreatments for electrodepositing nickel-phosphorus coatings on the Al alloy surface and proposed an electrodeposition model using anodic oxidation pretreatment.…”