Tribological properties of hexagonal boron nitride nanoparticles as a lubricating grease additive

Abstract

AbstractThe friction and anti‐wear behaviours of hexagonal boron nitride (h‐BN) nanoparticles as a lithium lubricating grease additive are being investigated under sliding conditions. The grease with 3 wt% 60 nm h‐BN particles and the grease with 1 wt% 500 nm h‐BN particles lead to 22.34% and 20.18% reductions in the wear scar diameter, respectively, although the friction coefficients slightly decrease. The boric acid H3BO3 with layer‐crystal structure produces during the friction process, and the synergistic effect of h‐BN nanoparticles and H3BO3 makes friction reduction and wear‐resistant enhancement. Furthermore, the 60 nm h‐BN particles filled in the asperity valleys of the friction surface make a rolling effect and establish a protective film, while the 500 nm h‐BN particles shield the asperity contact between friction pairs and make a polishing effect as well.