Synthesis and Tribological Properties of MXene/CoAl-LDH Heterostructure Nano-additives

Two-dimensional MXene (Ti 3 C 2 T x ) demonstrates significant potential for applications in tribology due to its exceptional interlayer shear behavior and high load-bearing capacity. However, its practical use is considerably limited by issues such as poor dispersibility, susceptibility to agglomeration in non-polar lubricating oils, and inadequate high-temperature oxidation resistance. To overcome these challenges, this study utilized a hydrothermal method to in-situ grow CoAl-LDH on the surface of Ti 3 C 2 T x , successfully creating a Ti 3 C 2 T x /CoAl-LDH composite. The steric hindrance effect of the heterostructure effectively addressed the dispersion stability problem of the additive in PAO6 base oil, while simultaneously enhancing the material’s oxidation resistance. Tribological tests indicate that, under conditions of 25 °C and 40 N, the incorporation of 0.2 wt% of this composite results in significant reductions in the average friction coefficient and wear volume of PAO6 base oil by 52.9 and 51.3%, respectively. At 200 °C and 40 N, the corresponding reductions are 39.1 and 39.4%. The remarkable friction-reducing and anti-wear performance can be attributed to the in-situ formation of a dense composite tribo-chemical film at the sliding interface during friction. This protective film, composed of Ti 3 C 2 T x , CoAl-LDH, metal oxides, and complex carbides, substantially enhances the load-bearing and lubricating properties of the contact interface.