Tribological properties of zirconium phosphate-quinoline compound as an additive in lithium grease

Abstract

Purpose The purpose of this paper is to study the tribological properties of (C9H8N)4(H2O)4[Zr8P12O40(OH)8F8] (designated as ZrPOF-Q1) used as an additive in lithium grease. Design/methodology/approach The tribological properties of ZrPOF-Q1 as an additive in the lithium grease were evaluated with a four-ball tester. To understand the lubrication mechanism, post-test characterization of the contact tracks was performed via three-dimensional (3D) optical profiler, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Findings The results reveal that ZrPOF-Q1 exhibits good performance in anti-wear, friction-reducing and load-carrying capacity. The action mechanism is estimated through analysis of the worn surface with SEM, EDS and 3D. The results indicate that ZrPOF-Q1 can adhere on the substrate, protecting the rubbed surfaces from a direct contact, even under high load for a long-time test. ZrPOF-Q1 can adhere on the substrate, protecting the rubbed surfaces from a direct contact, even under high load for a long-time test. Originality/value This work illustrates that ZrPOF-Q1 as an additive can improve lubricating performance. These tribological properties make ZrPOF-Q1 a promising candidate for lubricant additive.