A comparison of tribological properties of evenly distributed and agglomerated diamond nanoparticles in lubricated high-load steel–steel contact

The tribological properties of evenly distributed and agglomerated nanodiamonds on steel contact surfaces were compared in ethylene glycol lubricated tests using a pin-on-disc tribometer with a steel counter ball. The nanodiamond distributions were studied on silicon and steel surfaces using scanning electron microscopy. Friction and wear decreasing effects were observed with both sprayed and agglomerated nanodiamonds. The average friction coefficient with pure ethylene glycol lubricated contacts decreased from 0.16 to 0.12 with agglomerated nanodiamonds when 100N load was applied. A minimum for both disc wear rate (0.40×10−6mm3/Nm) and ball wear rate (0.29×10−6mm3/Nm) was observed with agglomerated nanodiamonds. One of the mechanisms of nanodiamond lubrication was observed to be the incorporation of nanodiamond particles in to the tribolayer. •Agglomerated and evenly distributed nanodiamonds were deposited on steel contact surfaces•Nanodiamond depositions decreased friction and wear in liquid lubrication•Friction coefficient decreased from 0.16 to 0.12 with agglomerated nanodiamonds