Diamond nanoparticles in ethylene glycol lubrication on steel–steel high load contact

Nanodiamond dispersions in ethylene glycol were applied in order to improve the boundary lubrication in high power density contacts. A range of nanodiamond concentrations in ethylene glycol were studied by stainless steel vs. stainless steel contact by a pin-on-disc tribometer. As compared to pure ethylene glycol, friction coefficient decreased from 0.16 to 0.11 when maximum concentration (3.7wt.% of nanodiamonds) and 100N normal load were applied. A minimum wear for both the disc and counter ball was detected when nanodiamond concentration of 2.2wt.% or 0.55wt.% was used. The mechanism of nanodiamond lubrication was determined to be incorporation of nanodiamonds into the tribolayer formation. ► Nanodiamond additives were successfully used in steel–steel contact lubrication. ► Nanodiamond addition into ethylene glycol lubricant decreased friction and wear. ► Friction coefficient decreased from 0.16 to 0.11 with 3.7wt.% concentration. ► Nanodiamonds incorporated into the tribofilm formation