Effective corrosion and wear protection of slippery liquid-infused porous surface on AZ31 Mg alloy

Magnesium alloys possess many exceptional advantages and attract much interest from researchers. However, the poor corrosion resistance significantly restricts their extensive applications in industry. Herein, a slippery liquid-infused porous surface (SLIPS), with good surface hydrophobicity, anti-corrosion, anti-wear, self-cleaning and self-healing performances, was developed on AZ31 Mg alloy. MgAl-layered double hydroxides (LDHs) with nanoporous structure were first in-situ synthesized on AZ31. Especially, an environmentally friendly corrosion inhibitor of sodium benzoate was intercalated into MgAl-LDHs to improve the corrosion resistance. After low-surface-energy modification and infusion of lubricant, the desired SLIPS with a homogeneous liquid layer was finally formed. The SLIPS showed good repellency to water to provide superior corrosion protection for the underlying AZ31, with the lowest corrosion current density of 1.93 × 10−9 A cm−2 and the largest impedance modulus of 1.18 × 107 Ω cm2. In comparison with the bare AZ31, the SLIPS exhibited enhanced friction-reducing and anti-wear performance because of the lubricating effect of the infused silicone oil and nanosheets of MgAl-LDHs. In addition, the SLIPS performed well in the self-cleaning and self-healing tests, showing potential to be widely used to enlarge the industrial applications of Mg alloys.