High-compact MXene-based coatings by controllable interfacial structures

Titanium carbide (Ti3C2Tx) MXenes have been regarded as important functional fillers of organic coatings for anticorrosion. Various MXene-based composite coatings have been fabricated and investigated via a material modification strategy, enhancing the corrosion protection performance. However, the anticorrosion reliabilities of MXene-based composite coatings were thwarted by their disordered interfaces. Significantly, few reports discuss the influence of interface structures on the protection performance for the coatings. In this work, we confirm the exceptional anticorrosion performance of ordered MXene/epoxy composite (OMC) coatings via a reasonable interface strategy. The ordered interfacial structure can synergistically enhance the coating compactness while maximizing the infiltration paths of aggressive species. The obtained OMC coating is compact and shows a high impedance of 6.84 × 109 Ohm cm2, a high coating resistance of 6.08 × 109 Ohm cm2, an extremely low porosity of 0.77% and an extremely low breakpoint frequency of 0.18 Hz, at a low filler content of 0.5 wt%. Besides, the concept of specific impedance (SZ) is proposed to attest the superiority of the OMC coating. Furthermore, the galvanic corrosion effects of MXenes in epoxy coatings are systematically explored and confirmed for the first time. The highly ordered structure eliminates the corrosion promotion activity of the conductive MXene, and thus, endows the superior anticorrosion stability for the coating. This work provides an inspiration for constructing outstanding long-term MXene-based anticorrosion coatings via regulating the coating interface.