The size effect of typical micro‐ and nano‐calcium carbonate additives on the friction properties of calcium sulfonate grease

Abstract This paper firstly reports the size effect of typical micro‐ and nano‐ calcium carbonate additives on the friction properties of calcium sulfonate grease. The rheological and tribological performance of calcium sulfonate grease with typical micro‐ and nano‐ calcium carbonate additives were investigated at 30 or 80°C by Rheometer and Optimol SRV‐V tester. To its surprise, calcium sulfonate grease with 5% calcium carbonate microparticles behave remarkable lubrication performance than calcium sulfonate grease with 5% calcium carbonate nanoparticles under boundary lubrication condition according to the rheological analysis and tribological evaluation. The enhancement in excellence tribological performance can be attributed to the synergistic effect between calcium carbonate microparticles and calcium carbonate in thickener of calcium sulfonate grease. The thin film composed of CaCO 3 and CaO on the worn surface generated by solid particles is conducive to reducing friction and wear.