Mechanism of Non-Amontons Boundary Friction of Fullerene Ball Nano-Additives

Investigating the relationship between the frictional performance and dynamic behavior of fullerenes under extreme conditions is crucial for the better development of fullerene-based lubricating materials. In this study, molecular dynamics simulations were used to investigate the boundary lubrication behavior of fullerenes confined between two carburized iron surfaces. Our findings demonstrate that the interlayer friction coefficient decreases exponentially with increasing applied load, increases with higher shear rates, and decreases with rising temperatures. The exponential decrease allows fullerenes to achieve ultra-low friction under high pressure, primarily due to their strong resistance to compressive deformation and the “ball-bearing effect”. Furthermore, as the applied pressure increases, the confinement becomes more pronounced, further accelerating the transition from sliding to rolling friction, thereby enhancing lubrication performance. This study deepens the understanding of the boundary lubrication mechanisms of fullerenes at carburized iron interfaces, offering valuable guidance for their application in advanced lubrication systems under extreme working conditions.