Mechanism for improvement of friction/wear by using Al2O3 and SiO2/Gear oil nanolubricants

Gear oil of heavy mining machineries are designed to provide anti-wear and anti-friction protection under extreme load condition. In present study thermophysical and tribological properties of industrial gear oil with nanoparticles additives (Al2O3 and SiO2) has been experimentally evaluated. Morphology of dry nanoparticles under FE-SEM shows that both nanoparticles are spherical. DLS test shows the presence of mild-agglomeration of nanoparticles in the dispersion. Density and viscosity of nanolubricants is tested with varying temperature and particle volume fraction. Measured viscosity results for Al2O3/gear oil nanolubricants follow the existing empirical model and new model has been proposed for SiO2/gear oil nanolubricants. Anti-friction and anti-wear properties of nanolubricants are tested on pin-on-disc test apparatus. FE-SEM and energy dispersive spectroscopy (EDS) analysis of wear scar (pin SS-304), evident the occurrence of ball bearing and surface polishing effects, which may be responsible for advanced tribological properties of the oil. Test results reveals that ball bearing have dominating effect in enhancement of tribological performance. [Display omitted] •Enhancing the tribological performance of the gear via Al2O3 and SiO2 nanoparticles.•Correlation proposed for the viscosity of gear oil nanolubricant.•Pin-on-disc tribotester displayed 25% and 22% improvement in anti-friction property with 0.3% Al2O3 and SiO2 nanoparticles.•FESEM and EDS analysis of wear scar reveals the dominance of ball bearing effect over surface polishing effect.