Robust macroscale superlubricity enabled by tribo-induced structure evolution of MoS2/metal superlattice coating

Structural superlubricity is of far-reaching significance for energy consumption control and carbon neutralization. Transforming macro-contact surface into myriad micro- or nano-contact points is a promising strategy to expand structural superlubricity to the macroscale. Yet how to spontaneously construct a robust multi-contact interface with incommensurate configuration during friction is challenging but is highly desirable for its practical application in different harsh environments. Here we report the experimental realization of macroscale superlubricity with a low environmental sensitivity in well-tuned MoS2/amorphous metal superlattice coating. Delicate experiments coupled with atomistic simulations reveal that amorphous metals undergo stress-induced nanocrystallization, and then spontaneously form nanoparticles with uniform size and distribution wrapped by randomly oriented MoS2 patches, achieving large-scale multi-contact at sliding interface. Finally, the robust superlubricity states of more than 1.0 x 106 cycles are achieved at high vacuum (1-2 x 10-2 Pa) with the strong support of the nanocrystalline/amorphous matrix formed under it. Moreover, this approach shows good applicability to different metal dopants, which provides a guidance to design the solid lubricant coatings enabling the actual applications of macroscale superlubricity for next-generation industrial equipment.

Automated summary

Structural superlubricity, achieved by transforming macro-contact surfaces into micro- or nano-contact points, has significant implications for energy consumption control and carbon neutralization. In this study, a robust multi-contact interface was spontaneously constructed during friction using a well-tuned MoS2/amorphous metal superlattice coating, resulting in macroscale superlubricity with low environmental sensitivity. The coating consisted of nanoparticles with uniform size and distribution wrapped by randomly oriented MoS2 patches, achieving large-scale multi-contact at the sliding interface and demonstrating excellent stability.