Facile one-step hydrothermal fabrication of Allium giganteum-like superhydrophobic coating on Mg alloy with self-cleaning and anti-corrosion properties

Superhydrophobic coating can act as the anti-corrosion layer for Mg alloy due to its water-repellency. The construction of such coating is dominated by the roughness and surface energy, which is expected to achieve in one-step to improve the weak adsorption phenomenon of surface modification during traditional approaches. Therefore, a superhydrophobic coating composed of CeO2 and cerium stearate (Ce(CH3(CH2)16COO)3) is fabricated via a facile hydrothermal method. The synthesis of Ce(CH3(CH2)16COO)3 passivates the surface of CeO2 nanosheets, leading to a reduction of surface energy and the formation of an Allium giganteum-like structure which presents a micro-nano hierarchical roughness. This unique structure with high roughness and low surface energy is responsible for the excellent superhydrophobic behavior of coating which has high water contact angle (WCA) of 164° and low rolling angle (RA) of 4.1°. The superhydrophobic coating also displays an outstanding self-cleaning behavior due to its low surface adhesion. The corrosion rate of prepared coating in 3.5 wt% NaCl aqueous solution is approximately two orders of magnitude lower than that of bare Mg alloy. This remarkably enhanced corrosion resistance arises from the decrease in contact area between the corrosion solution and sample due to the water-repellency of coating.