Tribological properties of lubricant additives of Fe, Cu and Co nanoparticles

Tribological investigations were performed on mineral oil containing Fe, Cu and Co nanoparticles and their combinations. The tribological tests showed that each set of nanoparticles significantly reduced the friction coefficient and wear (up to 1.5 times) of friction pairs. The use of Cu nanoparticles provides the most effective reduction of friction and wear in each combination of nanoparticles. Surface analysis shows that the constituent elements of nanoparticles precipitated on the contact surface during the use of the oils with nano-additives. Different structures formed on the friction surface are observed in the contact zone and over the remainder of the ball surface. The SEM micrographs and EDX chemical analysis confirm the formation of a tribo-layer composed of the elements from the nanoparticles.

► Oils with Fe, Cu and Co nanoparticles prepared by the new CEWLS method. ► Obvious reduction of friction and wear of friction pairs using the nano-additives. ► Efficiency of Cu nanoparticles and the use of mixtures of nanoparticles. ► Precipitation of nanoparticles' elements on the contact surface. ► Formation of protective layer of nanoparticle material during the operation.