Tribological performance of paraffin grease with silica nanoparticles as an additive

The present study deals to evaluate the physical properties, frictional behavior, and extreme pressure performance of paraffin grease dispersed with silica (SiO2) nanoparticles. The paraffin grease was developed using paraffin oil as a base oil and 12-lithium hydroxy stearate was chosen as a thickener. The concentration of thickener was fixed at 14% w/w. The SiO2 nanoparticles were synthesized by the modified sol-gel method and dispersed in paraffin grease by the in-situ method. The various analytical tools were used to ensure the formulation of SiO2 nanoparticles. The extreme pressure and frictional characteristics of SiO2 doped in paraffin grease were studied in four-ball tester as per ASTM D2596 and D2266, respectively. The physical properties of paraffin greases such as cone penetration, drop point, water washout, leakage tendency, and evaporation loss were also evaluated according to ASTM standards. The experimental results showed that the addition of SiO2 nanoparticles in paraffin grease enhances its tribological performances as compared to pure paraffin grease. The maximum reduction in coefficient of friction and mean wear volume was similar to 20% and similar to 42% at a concentration of 0.03 and 0.05% w/w, respectively.