Effect of initial surface treatment on obtaining a superhydrophobic surface on 5052 aluminum alloy with enhanced anticorrosion properties

Abstract Although there are many studies about superhydrophobicity on aluminum alloys substrates and their resistance to corrosion, few studies have evaluated the effect of the initial surface condition on obtaining super-hydrophobic surfaces. Different initial surface treatment (sanded, blasted and untreated) conditions were investigated on 5052 aluminum alloy to evaluate their influence on obtaining superhydrophobic surfaces with anticorrosive properties in saline medium. These surfaces were obtained in three sequential steps: acid etching in hydrochloric acid solution; chemical treatment in zinc nitrate in alkaline medium; and finally, reducing surface energy by using stearic acid. The characteristics of the surface were studied using scanning electron microscopy, energy dispersive spectroscopy, confocal microscopy and contact angle measurements. The corrosion resistance was evaluated by linear potentiodynamic polarization. The results revealed that the initial surface condition influenced the superhydrophobic and anticorrosion properties of the coatings. The sample initially sanded presented the best results of contact angle, sliding angle and efficiency of corrosion resistance, with values of 154°, 5.67° and 89.82%, respectively. However, after immersion corrosion test for 28 days, the coating lost superhydrophobic character and presented hydrophilic behavior.