Effect of lubricant additives of Cu, Fe and bimetallic CuFe nanoparticles on tribological properties.

Friction and wear reduction are widely sought to promote energy savings and reliability of moving machine components. Here, a combination of MST2 experiments and molecular dynamics (MD) simulations unveils the detailed lubrication mechanisms and presents quantitative wear descriptions of Cu and Fe nanoparticle (NP). The MD simulations results indicate that average value of friction force is reduced approximately 57.15% after the addition of Cu NP and these results is similar to the experimental results. In addition, bimetallic CuFe NP (Cu–Fe or Cu@Fe NP) shows superior performance than pure Cu NP, and the tribological properties of bimetallic CuFe NP change with structures. Bimetallic CuFe NP can be prepared and investigated by experimental methods, but the effects of different structures of bimetallic CuFe NP on lubrication are not sufficiently studied. The superior structure of bimetallic CuFe NP with higher load-carrying capacity and better tribological properties is predicted by MD simulations. Results from simulations suggest that there is an optimal NP structure and size that will minimize friction and wear for a given surface roughness. • The tribological properties of the bimetallic nanoparticles (NPs) are superior to those of the pure NPs. • MD simulations reveal the synergistic lubrication mechanism of the different structures of bimetallic NPs. • The bimetallic NPs of structures and sizes together affect the performance of lubricants. The best performance in terms of tribological properties and carrying capacity is achieved when the ratio of the NP diameter to surface roughness is 1.54. [ABSTRACT FROM AUTHOR]