Fabrication of a super-hydrophobic surface on a magnesium alloy by a simple method

A simple method, involving etching with copper(II) chloride and immersion in stearic acid, a low-surface-energy material, is used to fabricate a super-hydrophobic surface on magnesium alloy. Specimens modified by stearic acid show super-hydrophobicity, with the contact angle reaching 154°. SEM images show petal-shaped ridges, which form a three-dimensional porous structure containing voids that can trap air to form air cushions. These air cushions can prevent droplets from infiltrating the surface, thus leading to the super-hydrophobicity of the coating. Impedance and polarization analyses conducted in 3.5% NaCl aqueous solution show that electrochemical properties of the treated Mg alloy are significantly improved compared with the bare alloy, thereby enhancing its corrosion resistance. The super-hydrophobic surface also exhibits an excellent long-term durability in 3.5% NaCl aqueous solution. [Display omitted] •A simple method is used to fabricate a super-hydrophobic surface on magnesium alloy.•The petal-shaped microstructure played critical role in super-hydrophobicity.•The super-hydrophobic film exhibited good corrosion-resistance ability.•The super-hydrophobic film is well bonded with the substrate.