Hierarchical architecture of MXene/polypyrrole hybrid epoxy coating with superior anticorrosion and antistatic performance for Mg alloy

The existence of intrinsic defects in organic coating easily causes the degradation of protective ability during long-term corrosion process. A novel two-dimensional MXene (Ti3C2) nanofiller can effectively reduce the defect density and contribute to the enhancement of anticorrosion performance, while its high conductivity may accelerate the galvanic corrosion between the organic coating and underlying substrate. In this work, a kind of three-dimensional (3D) Ti3C2 MXene/polypyrrole composites (TPC) hybrid epoxy (EP) coating has been successfully fabricated on Mg alloy, which exhibits the excellent corrosion resistance and antistatic performance. The enhanced conductivity and synergistic barrier/passivation effect enable the Ti3C2 MXene/polypyrrole composites with low surface resistance and excellent anticorrosion ability. Based on the electrochemical tests, the TPC/EP coating possesses remarkable impedance value with 7.73 x 1010 omega cm2 after immersion for 14 days, representing the ability to extend service life due to the excellent physical barrier of Ti3C2 nanosheets and the migration of electrochemical interface related to electronic transmission derived from polypyrrole (PPy) nanoparticles. Moreover, the surface resistivity of the obtained coating is reduced to 2.76 x 108 omega, which can be ascribed to the transmission effect of electrolyte ions through interlayer of Ti3C2/PPy network structure, and thus improving its antistatic performance. This work not only highlights the application of 2D MXene material as effective anticorrosion filler, but pave a new avenue for the development of organic/inorganic hybrid coating of Mg alloy or other metallic materials.