Effect of morphology on tribological properties of Fe3O4 as lubricant additive: Nanospheres, nanowires and nanosheets

This work investigates the morphologies of Fe3O4 nanoparticles how to affect the tribological properties when they are applied as nano-lubricating additives. Fe3O4 nanoparticles with different morphologies (nanospheres, nanowires and nanosheets) are synthesized by solvothermal method and added in liquid paraffin to test the tribological properties. Although Fe3O4 nanoparticles can achieve certain anti-friction and anti-wear effects under the same conditions, the Fe3O4 nanospheres shows the best tribological properties. In the optimal concentrations of Fe3O4 nanospheres, nanowires and nanosheets, the changes of the average friction coefficient are almost the same, the wear volume are decreased by 91.03%, 86.88% and 87.63%, respectively. Fe3O4 nano particles with different morphologies can form films in the gap between friction pairs when they are used as additives, which ensures that three different Fe3O4 nanoparticles can enhance the tribological properties of the liquid paraffin. Compared with Fe3O4 nanowires and nanosheets, besides the tribological films, Fe3O4 nano spheres play roles in self-healing and rolling friction effects between friction pairs, resulting in the best anti friction and anti-wear.