Preparation and characterisation of AAO/Ni/Ni superhydrophobic coatings on aluminium alloys

Abstract

Superhydrophobic surfaces – driven from natural biology – are being increasingly studied in many engineering fields. This study fabricated hydrophobic AAO/Ni coatings and superhydrophobic AAO/Ni/Ni coatings based on aluminium alloy substrates. The surface morphologies of prepared samples were systematically examined, and the compositional analysis was conducted. Furthermore, the corrosion resistance of the superhydrophobic coatings was determined by electrochemical measurement. The AAO/Ni coatings revealed a micro-sized, lotus-like surface, showing hydrophobicity with a static water contact angle ranging from 133° to 148°. In contrast, the AAO/Ni/Ni samples possessed superhydrophobicity with a static water contact angle reaching 158° in this case. The corrosion results indicated the superior corrosion resistance of AAO/Ni/Ni, owing to both the surface roughness and surface organic modification. A detailed preparation pathway was proposed for the electrodeposition process of AAO/Ni/Ni. Among the tested samples, the AAO/Ni/Ni sample with the appropriate nickel electrodeposition duration showed the best superhydrophobicity and corrosion resistance.