Functionalisedh-BNas an effective lubricant additive inPAOoil forMoNcoating sliding againstSi3N4ball

Hexagonal boron nitride (h-BN) exhibits great potential for tribological applications due to its attractive 2D layered structure. In this work, functionalised hexagonal boron nitride (f-BN) was prepared by ultrasonic exfoliation of pristine h-BN in water and subsequent hydrothermal modification with sodium oleat. Fourier infrared spectra and X-ray photoelectron spectra analyses showed that long alkyl-chains were successfully grafted on the surface of f-BN by modification process. The tribological properties of the as-prepared f-BN as lubricant additive in poly-alpha-olefin 10 (PAO10) for lubricating MoN coating sliding against Si(3)N(4)ball were evaluated by a ball-on-disc friction tester. The friction coefficient and wear rate of the oil dispersed with 2 mg/mL f-BN was respectively reduced by 42% and 29% in comparison with the pure PAO10 oil, suggesting that f-BN was an effective lubricating additive for reducing friction and wear. Finally, the lubricating mechanism of f-BN dispersed in PAO10 was discussed and proposed.