Abstract
Superhydrophobic surfaces on 6082 aluminum alloy substrates are tailored by low-cost chemical surface treatments coupled to a fluorine-free alkyl-silane coating deposition. In particular, three different surface treatments are investigated: boiling water, HF/HCl, and HNO3/HCl etching. The results show that the micro-nano structure and the wetting behavior are greatly influenced by the applied surface texturing treatment. After silanization, all the textured surfaces exhibit a superhydrophobic behavior. The highest water contact angle (WCA, ≈180°) is obtained by HF/HCl etching. Interestingly, the water sliding angle (WSA) is affected by the anisotropic surface characteristics. Indeed, for the HF/HCl and the HNO3/HCl samples, the WSA in the longitudinal direction is lower than the transversal one, which slightly affects the self-cleaning capacity. The results point out that the superhydrophobic behavior of the aluminum alloys surface can be easily tailored by performing a two-step procedure: (i) roughening treatment and (ii) surface chemical silanization. Considering these promising results, the aim of further studies will be to improve the knowledge and optimize the process parameters in order to tailor a superhydrophobic surface with an effective performance in terms of stability and durability.
Highlights
Considering the above, the aim of the present work is to study the influence of the microstructure on aluminum superhydrophobic surfaces obtained by easy, efficient, industrially feasible, and economical approaches with the purpose of understanding the superhydrophobicity, micro-nano-roughness, and surface anisotropy
Further information can be discussed by comparing the sample morphology observed on the surface sample due to the applied chemical etching:
HNO3 /HCl etching: The surface was characterized by a bimodal structure
Summary
Aluminum and its alloys are an important class of engineering materials extensively used in different applications, especially in the transportation, aerospace, and civil industries [1,2,3,4] Their widespread use is due to their numerous properties, such as good conductivity, low specific weight, and high specific strength. The major drawback of aluminum alloys is the corrosion sensitivity in several environmental conditions, limiting its applicability for structural and functional applications, inducing relevant waste and serious contamination [5,6,7,8] To avoid this issue and extend their application fields, many researchers proposed the use of a corrosion inhibitor, organic and inorganic coating, chromate-based coating, and anodized layers or polymer duplex coatings [9,10,11,12,13,14,15,16]. These methods require complex processes, expensive equipment, and usually toxic chemical agents [17]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
