Customizing tribological interface structure on TC6 alloy by plasma electrolytic oxidation and Ti 3 C 2 nanocoating

Abstract To customize a self-lubricating tribological interface on titanium alloy surfaces and address the issues of high surface roughness and friction coefficient associated with porous plasma electrolytic oxidation (PEO) coatings, this study focused on the protective structure of the armadillo. A bioinspired “bone–skin” composite structure was designed by first depositing a high-strength coating (bone) on the titanium alloy surface via PEO, followed by the deposition of a Ti3C2 MXene nanocoating (skin) via a drop-casting method. The porous structure of the PEO coating enhances the confinement effect on the Ti3C2 nanoparticles, thereby improving their load-bearing capacity and significantly reducing interfacial friction and wear. This demonstrated a 67.8% increase in the microhardness and an order-of-magnitude reduction in the wear rate compared with those of the substrate. Tribological analysis revealed that the synergistic interaction between the low-shear Ti3C2 MXene nanoparticles and the TiO2-rich wear debris led to the formation of a protective tribofilm at the contact surface, effectively achieving both friction reduction and wear resistance. Friction and wear tests under different conditions further confirmed the stability of the PEO–Ti3C2 MXene interface structure. This study presents a novel interfacial design strategy using PEO and Ti3C2 MXenes that results in excellent tribological properties, providing new insights for their application in tribology.