Dispersion of novel 0D carbons in 15W40 engine oil using ultrasonication for enhanced lubrication

Carbon nanomaterials have been excellent additives in lubricants to considerably enhance their lubricity. In this work, we demonstrate using carbonaceous tyre pyrolysis waste (TPW) (a hazardous landfilling waste material) and onion-like carbon (OLC) particles as lubricant additives in 15W40 engine oil, a well-known commercial oil (CO). Using a sustainable method, TPW was converted into high-purity (99.9%) OLC particles at a kg scale. Different concentrations of TPW and OLC particles are dispersed in the CO using ultrasonication, and the lubricity of the additives-dispersed CO samples was assessed as per ASTM D 4172. Adding TPW and OLC particles in varying concentrations into the CO lowered the viscosity and internal fluid shear stress. Tribological tests showed that the coefficient of friction (CoF) was improved by 15.9% and 17.33% when 0.1wt.% of TPW and OLC particles were dispersed in CO, respectively. The spherical morphology of TPW and OLC particles is beneficial in generating a nano-rolling effect at the interface of the test specimens, leading to lower CoF and wear. However, the OLC particles do not prove effective in improving the wear resistance of the CO, but TPW in low concentrations in CO curtails friction and wear significantly.