Superhydrophobic Surfaces Based on Nickel Stearate: An Innovative Approach to Coatings on 7050 Aeronautical Aluminum Alloy

A metallic surface can exhibit low wettability through the formation of a rough structure with micro/nanometric dimensions combined with a surface energy-reducing agent. When the contact and sliding angles are ≥ 150° and ≤ 10°, respectively, the surface is classified as superhydrophobic (SHS). The study aimed to electrodeposit a microstructure with micronanometric roughness of nickel, stearic acid (Al/Ni-SA), and nickel, stearic acid with multi-layered carbon nanotubes (Al/Ni-SA-MWCNT) on aeronautical aluminum 7050. The obtained contact angles were close to 160°, and sliding angles were less than 1°, characterizing the superhydrophobic and self-cleaning nature. Freezing tests were conducted, and the deposit with MWCNT showed longer freezing times at -22°C. The Al/Ni-SA-MWCNT condition also exhibited the best corrosion resistance with corrosion current superior by two orders of magnitude compared to the Al/Ni-Sa condition. The coatings demonstrated impressive performance, achieving corrosion inhibition efficiencies close to 100%.

Keywords:
Superhydrophobicity; AA7050; MWCNT; Ice-resistant; Nickel stearate; Aeronautical