Photothermally Triggered Phase-Change Solid Slippery Surface with Self-Healing for Durable Corrosion Protection of Magnesium Alloy.

Slippery liquid-infused porous surfaces (SLIPS) have shown great potential in anti-corrosion applications because of excellent liquid repellency and barrier properties. However, the inevitable depletion and migration of liquid lubricants, together with limited mechanical durability, severely restrict the long-term anti-corrosion performance. In this work, a photothermally triggered phase-change solid slippery surface (SSS) with self-healing capability was developed on magnesium alloy by infusing paraffin into a natural wollastonite (NW)/ZIF-67/GO hierarchical structure. Electrochemical measurements demonstrate that the SSS exhibits an ultralow corrosion current density of 1.442 × 10-9 A cm-2, which is five orders of magnitude lower than that of bare Mg alloy, together with a high polarization resistance of 8.537 × 108 Ω and a corrosion protection efficiency of 99.99%. After photothermal self-healing, the healed SSS still maintains a low corrosion current density of 3.907 × 10-8 A cm-2 and a protection efficiency of 99.97%, confirming the effective recovery of its barrier performance. Moreover, the low-frequency impedance modulus at 0.01 Hz remains at the 105 Ω cm2 level even after 240 h of immersion in a 3.5 wt % NaCl solution, indicating durable corrosion resistance. In addition, owing to the synergistic effects of paraffin sealing, porous confinement, and photothermal responsiveness, the obtained SSS exhibits excellent anti-contamination behavior, remarkable stability against water-jet impact, ultrasonic treatment, and acid/alkali exposure, as well as rapid scratch repair. This work offers new insight into the design of long-term anti-corrosion coatings for magnesium alloys.