Corrosion resistance of a superhydrophobic dodecyltrimethoxysilane coating on magnesium hydroxide-pretreated magnesium alloy AZ31 by electrodeposition

Superhydrophobic coatings can remarkably improve the anti-corrosion performance of many materials. In this study, a fluorine-free superhydrophobic Mg(OH) 2 /DTMS composite coating was successfully fabricated on the surface of Mg alloy AZ31 by hydrothermal process and electrodeposition of dodecyltrimethoxysilane to enhance corrosion resistance . The corrosion resistance of the coating was tested using a potentiodynamic polarization scan, electrochemical impedance spectroscopy (EIS), and hydrogen evolution measurements. The superhydrophobicity was investigated by measuring water contact angles and sliding angles. The results showed that the Mg(OH) 2 /DTMS composite coating was composed of walnut-like micro/nanostructures and exhibited superhydrophobicity with a contact angle of 165.1° ± 2.1° and a sliding angle of 3.5° ± 0.6°. Moreover, the corrosion current density of the composite coating (1.777 × 10 −8 A·cm −2 ) decreased about three orders of magnitude compared with uncoated AZ31 substrate (7.342 × 10 −5 A·cm −2 ), suggesting that the composite coating had excellent corrosion resistance. Finally, the anti-corrosion mechanism of the composite coating was also addressed.