A General Engineering Applicable Superlubricity: Hydrogenated Amorphous Carbon Film Containing Nano Diamond Particles

Designing promising mechanical systems with ultra-low friction performance and establishing superlubricity regimes are desirable not only to greatly save energy but also to reduce hazardous waste emissions. However, very few macroscale superlubricity regimes for engineering applications have been reported. Here, this study demonstrates that sustained superlubricity can be achieved at engineering scale when the contact pressure is higher than 2 GPa. Such engineering superlubricity originates from the in situ formation of curved graphene ribbons or onion carbon tribofilms at the sliding interface. Experimental data also demonstrate that the wear of the amorphous carbon film containing some nanodiamond particles against Al2O3 ball is consistent with atomic attrition. A feasible two-stage mechanism is proposed to explain the friction and wear behaviors. This finding in amorphous carbon films will not only enrich the understanding of superlubricity behavior but also be helpful to establish more superlubricity regimes for more engineering applications.