Towards superlow friction and wear with polysiloxane/Ti₃C₂T_x nanocomposite film and polyalphaolefin oil

Minimizing friction and wear remains a big challenge for mechanical mobility systems and energy saving. We demonstrate that a remarkable synergistic lubrication effect could be induced with a novel “soft” and “hard” polysiloxane (PS)/Ti₃C₂T_x nanocomposite coating and the industrial PAO4 lubricant oil, with the lowest friction of 0.01 together with negligible wear achieved for PS/Ti₃C₂T_x-400. Careful investigation of the friction surface for PS/Ti₃C₂T_x-400 indicates that a mated surface topology, enhanced boundary lubrication filming-forming ability, and local accumulation of Ti₃C₂T_x MXene nanoflakes could be induced at the interface, which creates desirable synergistic lubrication effects to not only effectively separate the mating surfaces and prevent the direct asperity contacts, but also form in-situ shearing layers to play a positive role in friction reduction. Furthermore, the surface hardening effect could also be observed on the PS/Ti₃C₂T_x-400 coating surface, with pyridinic N transformed into robust pyrrolic N. It could be expected that the results of this work would play a catalytic role in the promotion of superlubricity in the future engineering applications.