Tribological properties of core/shell Fe3O4/TiO2 composites as additives in base oil

In this research, tribological properties of Fe3O4/TiO2 composites were investigated. To improve the tribological properties and dispersion of Fe3O4 nano-lubricant additives, the nanoparticles were modified via the Stöber method, then TiO2 shells were successfully coated on the Fe3O4 surface with chemical techniques. The results showed that the average particle size of Fe3O4/TiO2 nanostructures was about 360–420 nm. The TiO2 shell with a thickness of about 36 nm is deposited on the surface of Fe3O4. The tribological performance of base oil including Fe3O4/TiO2 nanostructures were determined by a ball-on-disk tribometer. Results of friction tests showed that the Fe3O4/TiO2 nanostructures can reduce the friction coefficient by 7.78% compared to base oil. The average wear volume and wear scar width of base oil with 0.25 wt% Fe3O4/TiO2 additive compared to pure base oil decreased by 44.47% and 11.02%, respectively, which can be correlated to the synergistic effect of TiO2 and Fe3O4 from the Fe3O4/TiO2 composites.