Tribological behavior of zirconium phosphate‐1,4‐dimethylpiperazine compound as lubricant additives

Abstract

AbstractZirconium phosphate compound, [C6H16N2]0.5Zr‐(H0.5PO4)2•H2O designated as ZrPO4‐DES8 have been synthesised hydrothermally in the presence of 1,4‐dimethylpiperazine (DMP). In this study, small (0.5‐0.8 μm) and large (8‐10 μm) ZrPO4‐DES8 particles were obtained by varying the amount of H3PO4 in the HF ‐ ZrO2‐P2O5‐DMP‐H2O hydrothermal system. The tribological properties of ZrPO4‐DES8 particles as additives in lithium grease were evaluated by using a ball‐on‐disk reciprocating tribometer under different concentrations, loads, and frequencies. The results illustrated that ZrPO4‐DES8 particles improved the lubricating performance of grease substantially. The small‐sized particles exhibited better and more stable friction reduction and anti‐wear performance than larger ones during sliding. The characterisation of a possible wear mechanism was given by observing the worn surface under a three‐dimensional optical profiler, a scanning electron microscope and energy dispersive X‐ray analysis. The simple synthetic method and superior tribological properties make the ZrPO4‐DES8 become a choice for lubricant additives.