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5320882 
Journal Article 
Superhydrophobic aluminum alloy surfaces prepared by chemical etching process and their corrosion resistance properties 
Huang, Y; Sarkar, DK; Chen, XG 
2015 
Yes 
Applied Surface Science
ISSN: 0169-4332 
356 
1012-1024 
WOS:000365351600133 
Superhydrophobic aluminum alloy surfaces are obtained by chemical etching using 1 M NaOH solution followed by passivation using 0.01 M ethanolic stearic acid (SA) solution. The formation of low surface energy aluminum stearate takes place during the passivation process between stearic acid and hydroxyl group-terminated aluminum alloy surfaces. A schematic model of the SA passivation process on the -OH terminated Al-surfaces is presented in this work. The flake-like micro-nanostructure morphology of the low surface energy aluminum stearate increases the water contact angle by more than 150, demonstrating the superhydrophobic properties. The corrosion current density reduces and polarization resistance increases systematically with increasing passivation time. The polarization resistance, calculated from the Tafel curve of the superhydrophobic surfaces prepared by stearic acid passivation for 60 min, is determined to be 137 times larger than that of the as-received aluminum alloy substrate. Similarly, the modulus of impedance, as-determined from electrochemical impedance spectroscopy (EIS), is found to be 70 times larger for the superhydrophobic surfaces compared with the as-received aluminum alloy surface. These results demonstrate that the superhydrophobic aluminum alloy surfaces created by chemical etching followed by passivation have superior corrosion resistance properties than the as-receive aluminum alloy substrate. (C) 2015 Elsevier B.V. All rights reserved. 
Corrosion resistance; Superhydrophobic aluminum alloy surfaces; Chemical etching; Aluminum stearate; Potentiodynamic polarization; Electrochemical impedance spectroscopy (EIS)