Synergistic lubrication effects and tribological properties of graphene/oil-based lubricant systems

Abstract

Graphene exhibits great potential as an additive to enhance the anti-wear and friction reduction capacity of moving mechanical components in a synergistic mechanism with the base oil. This paper considers the effect of different factors such as the number of base oil molecules, graphene content, normal load, sliding velocity and the presence of graphene. The synergistic mechanism of graphene and base oil is investigated by experiments and molecular dynamics (MD) simulations. The results show that the friction and wear reduction is due to the formation of the load-supporting graphene layers and sufficient base oil molecules between Fe slabs. Graphene can stably adsorb on the rubbing surfaces lubricated by the base oil, confirming that graphene can form a physical deposition film on rubbing surfaces. Low friction and wear can be achieved with higher sliding velocity and lower load. Furthermore, compared to the sliding velocity, the load significantly affects the mean square displacement of base oil and oleic acid molecules. These outcomes provide a better understanding of the tribological properties of graphene as a lubricant additive.

Study on the Sliding Tribological Behavior of Oleic Acid-Modified MoS2 under Boundary Lubrication

“…The MSD values can be used to evaluate the diffusional mobility of the molecules. 36 MSD calculation adopts eq 6:…”

“…The diffusion of the base lipid and additive molecules was further investigated by calculating the mean square displacement (MSD). The MSD values can be used to evaluate the diffusional mobility of the molecules . MSD calculation adopts eq : MSD ( t ) = 1 N ( ∑ i = 1 N | r i false( t false) − r i false( t 0 false) | 2 ) where N is the total number of atoms, r i ( t ) is the position of the atom i at time t , and r i ( t 0 ) is the initial position of the atom.…”

Lubrication Performance under Electrical Regulation: Investigating the Mechanism of Graphene/Ionic Liquid Composite Materials

“…This effectively reduces both the friction coe cient and the wear rate. [13] . However, the presence of an electric eld can affect graphene's binding properties at friction interfaces, primarily due to its in uence on graphene's internal structure and charge distribution.…”