A Novel Simple Fabrication Method for Mechanically Robust Superhydrophobic 2024 Aluminum Alloy Surfaces

Abstract

The mechanical durability of a superhydrophobic aluminum alloy surface is an important indicator of its practical use. Herein, we propose a strategy to prepare a superhydrophobic 2024 aluminum alloy surface with highly enhanced mechanical durability by using a two-step chemical etching method, using a NaOH solution as the etchant in step one and a Na2CO3 solution as the etchant in step two. Robust mechanical durability was studied by static contact angle tests before and after an abrasion test, potentiodynamic polarization measurements after an abrasion test and electrochemical impedance spectroscopy tests after an abrasion test. Furthermore, the mechanism for enhanced mechanical durability was investigated through scanning of electron microscopy images, energy-dispersive X-ray spectra, Fourier transform infrared spectra and X-ray photoelectron spectra. The testing results indicate that a hierarchical rough surface consisting of regular micro-scale dents and some nano-scale fibers in the micro-scale dents, obtained with the two-step chemical etching method, contributes to highly enhanced mechanical durability. Meanwhile, the as-prepared superhydrophobic 2024 aluminum alloy surface retained a silvery color instead of the black shown on the superhydrophobic 2024 aluminum alloy surface prepared by a conventional one-step chemical etching method using NaOH solution as the etchant.

The Preparation of a Superhydrophobic Fluorine Rubber Surface

“…First, the surface of the material should have a rough micro-nano structure, and second, the surface of the material should be modified with low-surface-energy substances [7]. At present, the relatively mature methods to prepare superhydrophobic surfaces mainly include the template method [8,9], the layer-by-layer self-assembly method [10,11], the deposition method [12], the electrostatic spinning method [13], the etching method [14], the phase separation method [15], and so on. A superhydrophobic surface has excellent hydrophobicity, and its special wettability makes superhydrophobic surfaces widely used in self-cleaning [16], anti-icing [17], anti-corrosion [18], oil-water separation [19], and other fields.…”