Preparation of slippery liquid-infused porous surface based on MgAlLa-layered double hydroxide for effective corrosion protection on AZ31 Mg alloy

• MgAlLa-LDH is in-situ synthesized on AZ31 Mg alloy. • The nanopores of LDH provide accommodation for silicone oil to form a SLIPS. • The SLIPS provides better corrosion protection than a superhydrophobic coating. • Corrosion inhibitor of NaB is detected by HPLC after immersion test. • The SLIPS shows good self-cleaning and self-healing performances. The relatively poor corrosion resistance of magnesium (Mg) alloys significantly restricts their extensive applications in industry despite their superior properties such as good electromagnetic shielding, low density, and good biocompatibility. The formation of a protective coating, especially a hydrophobic coating, can provide corrosion protection for the underlying Mg alloys. Herein, a slippery liquid-infused porous surface (SLIPS) with good hydrophobicity was developed by infusing MgAlLa-layered double hydroxide (LDH) with silicone oil. In particular, the MgAlLa-LDH was intercalated with sodium benzoate to further improve the corrosion resistance. A homogeneous liquid layer was generated on the SLIPS, which can effectively prevent corrosion from external corrosive species. Compared with a superhydrophobic coating, the SLIPS showed better corrosion protection in both electrochemical and immersion tests, attributed to the better stability of liquid layer than air pockets. After immersion in 3.5 wt.% NaCl solution for 7 days, no obvious corrosion was observed on the SLIPS. Moreover, the SLIPS presents good self-cleaning and self-healing properties. These good performances made the SLIPS possible to be extensively applied in practice.