Atomistic Mechanism of Friction-Force Independence on the Normal Load and Other Friction Laws for Dynamic Structural Superlubricity.
Phys Rev Lett
; 131(26): 266201, 2023 Dec 29.
Article
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| MEDLINE
| ID: mdl-38215361
ABSTRACT
We explore dynamic structural superlubricity for the case of a relatively large contact area, where the friction force is proportional to the area (exceeding â¼100 nm^{2}) experimentally, numerically, and theoretically. We use a setup composed of two molecular smooth incommensurate surfaces graphene-covered tip and substrate. The experiments and molecular dynamic simulations demonstrate independence of the friction force on the normal load for a wide range of normal loads and relative surface velocities. We propose an atomistic mechanism for this phenomenon, associated with synchronic out-of-plane surface fluctuations of thermal origin, and confirm it by numerical experiments. Based on this mechanism, we develop a theory for this type of superlubricity and show that friction force increases linearly with increasing temperature and relative velocity for velocities larger than a threshold velocity. The molecular dynamic results are in a fair agreement with predictions of the theory.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Año:
2023
Tipo del documento:
Article
País de afiliación:
Rusia
Pais de publicación:
Estados Unidos