Customizing tribological interface structure in TC6 alloy by plasma electrolytic oxidation and Ti₃C₂ nanocoating

To customizing a self-lubricating tribological interface on titanium alloy surfaces and address the issues of high surface roughness and friction coefficient associated with the porous Plasma electrolytic oxidation (PEO) coating, this study drew inspiration from 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) using a drop-casting method. The porous structure of the PEO coating enhances the confinement effect on Ti₃C₂ nanoparticles, thereby improving its load-bearing capacity and significantly reducing interfacial friction and wear. Demonstrating a 67.8% increase in microhardness and an order-of-magnitude reduction in wear rate compared to the substrate. Tribological analysis reveals that the synergistic interaction between the low-shear Ti₃C₂ MXene nanoparticles and the TiO₂-rich wear debris leads 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 PEO-Ti₃C₂ MXene interface structure. This study presents a novel interfacial design strategy using PEO and Ti₃C₂ MXene that exhibits excellent tribological properties, offering new insights for its application in tribology.