Towards superlow friction and wear with polysiloxane/Ti3C2Tx 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)/Ti3C2Tx nanocomposite coating and the industrial PAO4 lubricant oil, with the lowest friction of 0.01 together with negligible wear achieved for PS/Ti3C2Tx-400. Careful investigation of the friction surface for PS/Ti3C2Tx-400 indicates that a mated surface topology, enhanced boundary lubrication filming-forming ability, and local accumulation of Ti3C2Tx 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/Ti3C2Tx-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.