Lubricating mechanism of Fe3O4@MoS2 core-shell nanocomposites as oil additives for steel/steel contact

Fe3O4 nanospheres, MoS2 nanospheres and Fe3O4@MoS2 nanocomposites were used as lubricating oil additives for steel/steel contact and dispersed in PAO4 base oil. Tribological behavior and wear mechanisms of the steel/steel contacts were investigated. The results indicate that the friction coefficient increased with the addition of Fe3O4 nanospheres and decreased with the addition of MoS2 nanospheres. Their wear types belonged to abrasive wear and furrow wear respectively. In addition, Fe3O4@MoS2 nanocomposites as lubricating additive had excellent lubricating performance and energy-saving potential due to the formation of a stable adsorbed film and a robust tribo-film on the rubbing surfaces which resulted in a mild furrow wear for steel/steel contact.