Low-cost and large-scale fabrication of a superhydrophobic 5052 aluminum alloy surface with enhanced corrosion resistance

Superhydrophobic 5052 aluminum alloy substrates with excellent corrosion resistance have been fabricated by a simple and low-cost method of acid treatment and modification of fluoroalkyl-silane combined with surface passivation. Via an etching process with hydrochloric acid, hierarchical convex-concave micro/nano-structures have been formed on 5052 aluminum alloy surfaces. Then they were covered with a flocculent layer after passivation with potassium permanganate. The wettability and corrosion resistance of the as-prepared substrates have been systematically investigated. The results indicate that aluminum alloy substrates with an etching time of 5 min and passivation time of 180 min exhibit good superhydrophobicity with a water contact angle of 153 +/- 0.7 degrees. In addition, corrosion resistance was also explored by potentiodynamic polarization curves and electrochemical impedance spectroscopy. Clearly, the corrosion resistance of the as-prepared aluminum alloy substrates has been greatly enhanced, which will be positive to extend further the applications of Al alloys in engineering fields, such as shipbuilding and oceanographic engineering.