Corrosion resistance and near-infrared light induced self-healing behavior of polycaprolactone coating with MIL-53@TA on magnesium alloy

• A NIR-induced self-healing MIL-53@TA/PCL coating was designed and prepared by using MIL-53@TA as photothermal agent and PCL as low-melting-point layer. • The MIL-53@TA/PCL composite coating possesses excellent photothermal property. • The MIL-53@TA/PCL composite coating greatly improves corrosion resistance of Mg alloy. • The scratched MIL-53@TA/PCL coating can be healed within 10 min irradiated by 808 nm NIR (0.17 W/cm 2 ) A novel self-healing composite coating was fabricated on magnesium alloy by using polycaprolactone (PCL) as resin matrix and iron-based metal-organic framework MIL-53 modified with tannic acid (TA) as function filler. The surface morphology, structure and wettability of composite coating were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and sessile water droplet static contact angle. The corrosion resistance and healing performance of PCL coatings was determined by electrochemical impedance spectroscopy (EIS) and photothermal tests. Results indicate that MIL-53@TA/PCL coating possesses a flatter surface, a higher corrosion resistance and better photothermal effect than that of blank PCL coating and MIL-53/PCL coating. Under the near-infrared (NIR) laser irradiation with the wave length of 808 nm, the scratched MIL-53@TA/PCL coating could be healed within 10 min because of the excellent photothermal conversion ability of MIL-53@TA component.