Abstract: The tribological properties of the lithium grease with layered α-zirconium phosphates (α-ZrP and Cu-α-ZrP) additives were evaluated on steel-steel friction pair with a four - ball tester. The worn surfaces were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and 3D optical profiler to investigate the worn surface morphology, element composition and bulk worn loss. The results show that both of α-ZrP and Cu-α-ZrP can exhibit a good performance of the lithium grease in anti-wear and anti-friction and bearing load-carrying capacity under extreme pressure. The protective film formed on the worn surface during the friction process mainly contains α-ZrP or Cu-α-ZrP, leading to a good tribological performance.

Key words: lithium grease, layered α-zirconium phosphate, additive, friction and wear property