Non-additized batches of lubricating greases were tribologically characterized through traction coefficient and Stribeck curves at different operating conditions on a ball-on-disc test rig, ensuring that the contact was fully flooded. The tests were performed at constant load, but different operating temperatures while varying the slide-to roll ratio (SRR) or the rolling entrainment speed.
The results were correlated to the greases׳ formulation in terms of base oil viscosity, thickener and/or elastomer content. A relationship between the coefficient of friction (COF) of greases formulated with different thickener content was found and the thickener influence on the COF was addressed.
Keywords: Polymer greases, Coefficient of friction, Stribeck curves