Experimental Study on the Impact of Variable Concentration of Graphite Nanoparticles on the Tribological Behaviour of 15W40 Lubricating Oil

An experiment examined the impact of 0.2% to 1.0% w/w graphite nanoparticles in 15W40 lubricating oil on tribological and rheological behaviour. Analysis, conducted with a pin-on-disc machine and four-ball tester, revealed improved tribological properties and a 30% reduction in friction coefficient compared to fresh 15W40. Wear was negligible, and extreme-pressure performance increased by approximately 20%. SEM morphology confirmed the presence of graphite nanoparticles on the tribo-pair surface, indicating enhanced lubricant performance.