摘要
Magnesium (Mg) alloys are widely used in aerospace and automotive industries due to their high specific strength, low density, and excellent electromagnetic shielding properties. However, their poor corrosion resistance limits long-term service reliability. Herein, multifunctional MXene/chitosan/polypyrrole (MCPY) hybrid microcontainers with acid-responsive release behavior are successfully fabricated and incorporated into an epoxy (EP) matrix to construct a smart anti-corrosion coating (EP@MCPY) for AZ31 Mg alloy. In this system, chitosan (CS) microspheres function as pH-responsive containers for the controlled release of polypyrrole (PPy), while two-dimensional MXene nanosheets simultaneously improve filler dispersion and enhance barrier performance through a labyrinth effect. Under acidic conditions, protonation-induced expansion of CS trigger the release of PPy, which promotes passive film stabilization through redox reactions, thereby providing active corrosion protection. Electrochemical tests reveal that after 14 days of immersion in a 3.5 wt% NaCl solution, the EP@MCPY coating maintains a high |Z| f=0.01 Hz of 1.06 × 10 11 Ω·cm 2 , significantly outperforming both pure EP and the chitosan/polypyrrole (CSPY) composite coating. In an acidic corrosive medium (pH = 3), the scratched EP@MCPY coating exhibits notable self-healing behavior, with its |Z| f=0.01 Hz increasing from 6.90 × 10 5 Ω·cm 2 to 2.13 × 10 6 Ω·cm 2 within 12 h, confirming the intelligent protective functionality of the coating under acidic conditions. The superior protective performance is attributed to the synergistic integration of MXene-enabled passive barrier protection and CSPY-mediated active corrosion inhibition. This work provides an effective strategy for developing multifunctional smart coatings with long-term corrosion resistance and self-healing capability for Mg alloys. Download: Download high-res image (165KB) Download: Download full-size image
危险品化学品经营许可证（带存储）