The development of double-barrier anticorrosion coating by embedding CNTs/MXene@ZnFe-MoO4 LDH in the waterborne epoxy resin

The anticorrosion of coatings could be effectively enhanced using two-dimensional Ti₃C₂T_x MXene. Nevertheless, its natural accumulation tendency in the waterborne epoxy (WEP) resin resulted in the formation of pores and fractures of coatings, and could not completely prevent the invasion of corrosive media. To address the issue, a novel heterostructure network CNTs/MXene@ZnFe-MoO₄ LDH (CML) nanofiller was successfully synthesized using electrostatic adsorption and in-situ growth methods, which was then introduced into WEP to prepare CML/WEP composite coating. The effect of CML filler on the interfacial compatibility and barrier properties of the coating was explored, and the corrosion resistance and antiwear mechanisms of the coating were analyzed. The results showed that after 0.5 h of friction, the wear rate (Wr) of the CML/WEP coating was reduced by 85.46 % compared to that of the WEP coating. The |Z|_0.01 Hz value of the CML/WEP coating remained at a high level (5.84 ×10⁷ Ω·cm²) after 28 d of immersion. According to density functional theory (DFT) calculations, the free energies of FeMoO₄, Fe₂(MoO₄)₃, and Zn(OH)₂ on the metal substrate were −2.13 eV, −1.86 eV, and −1.57 eV, respectively, confirming successful release of corrosion inhibitors in the coating and the formation of a stable protective film. The CML filler exhibited remarkable dispersibility, barrier properties, and release capability of corrosion inhibitor. The micro-network structure of CML endowed WEP coatings with superior corrosion resistance and wear resistance. This study provided significant insights into the development of high-performance coating materials for industrial equipment protection.