When mussel meets lotus leaf and pitcher plant: A combinational biomimetic strategy for Mg-Li corrosion inhibition

Abstract

Magnesium-lithium alloys hold immense promise as lightweight structural materials due to combination of unique properties. However, their widespread application is hindered by the inherent poor corrosion resistance. This research presents a novel and cost-effective approach to address this obstacle by utilizing metal-phenol networks inspired by mussel as surface modifiers. These networks facilitate the deposition of nanoparticle on magnesium-lithium (Mg-Li) alloys through chemical reactions between phenolic groups and metal ions. The resulting surface is further enhanced by spray-coating a sheet-like biomimetic superhydrophobic surface (SHS) of alkyl-ketone dimer (AKD), subsequently followed by lubricant infusion with dimethylsilicone oil to create a slippery liquid-infused porous surface (SLIPS). Characterization using multiple techniques confirms the chemical composition and morphology of the modified surface, which significantly improves the corrosion resistance of the magnesium-lithium alloy. Importantly, scanning Kelvin probe measurements reveal that SHS and SLIPS enhance the atmospheric corrosion resistance of the material. Further validation in 3.5 wt% NaCl solution demonstrates remarkable effectiveness of SLIPS. During the initial stages of immersion, the impedance magnitude |Z|0.01 Hz for SLIPS reaches a remarkable 3.78 × 107 Ω·cm2, exceeding those of the SHS, TA-LA141, and bare LA141 by 3, 3, and 6 orders of magnitude, respectively. This performance persists even after long-term immersion, with the SLIPS coating still exhibiting an impedance value one order of magnitude higher than the SHS after extended exposure. These results establish the effectiveness of SLIPS as a promising candidate for significantly upgrading the corrosion resistance of Mg-Li alloy, paving the way for their broader utilization in demanding fields.