In-situ formation of tribofilm with Ti₃C₂T_x MXene nanoflakes triggers macroscale superlubricity

In the present work, a robust macroscale superlubricity state was achieved with a coefficient of friction (COF) of 0.002 by introducing Ti₃C₂T_x MXene nanoflakes in glycerol at Si₃N₄/sapphire interfaces. The MXene-glycerol solution results in the reduction of COF by 96.90% and 97.87% compared to those of pristine glycerol and Ti₃C₂T_x MXene solutions, respectively. The friction reduction of MXene-glycerol is attributed to the in-situ formation of tribofilm containing Ti₃C₂T_x MXene nanoflakes and tribochemical layer with Ti₃C₂T_x MXene on friction pairs, leading to the reduction of shear stress and wear between surface asperities. The synergistic effect between Ti₃C₂T_x MXene and glycerol enhanced the lubrication performance of Ti₃C₂T_x MXene, triggering liquid-superlubricity at the macroscale.