Molecular dynamics study of the frictional properties of multilayer MoS2

To reveal the friction mechanism of molybdenum disulfide (MoS₂), the frictional properties of multilayer MoS₂ lubrication film were studied under variable loads and shearing velocities by the molecular dynamics (MD) method. The results showed irreversible deformation of MoS₂ was caused by heavy load or high shear velocity during the friction process and the interlayer velocity changed from a linear to a ladder-like distribution; thus, the number of shear surfaces and the friction coefficient decreased. The low friction coefficient caused by heavy load or high velocity could be maintained with a decrease in load or velocity. For a solid MoS₂ lubrication film, the number of shearing surfaces should be reduced as much as possible and the friction pair should be run under heavy load or high shear velocity for a period of time in advance; thus, it could exhibit excellent frictional properties under other conditions. The proposed friction mechanism provided theoretical guidance for experiments to further improve the frictional properties of MoS₂.

Deformation of MoS₂ layers directly leads to decrease in potential and ultimately leads to decrease in friction coefficient.