Rheological and Tribological Properties of Zirconium Phosphate (ZrP) Intercalation Compounds as Lubricating Grease Thickener

Abstract

This research studied layered zirconium phosphate intercalated with octadecyltrimethylammonium bromide (STAB-ZrP) as a thickener by thickening five types of base oils. The thickening ability and fluidity behavior of STAB-ZrP gel were evaluated using rheological measurements. The tribological properties of STAB-ZrP gel were investigated using a reciprocating tribometer under temperatures of 25 °C and −15 °C. The rheological results showed that STAB-ZrP gel had grease-like characteristics. Naphthenic and alkyl naphthalene as the base oil can lead to the higher thickening ability. Naphthenic oil maintained the most colloidal stability at 25 °C and −15 °C. STAB-ZrP gel exhibited superior anti-wear and friction reduction, owing to the formation of a solid protective film on the contact interface. The layered structure and morphology of STAB-ZrP after thickening were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). This research established the relationship of STAB-ZrP with base oils in terms of their performance. STAB-ZrP acts as both a thickener and a solid additive in the STAB-ZrP gel system. This study can serve a beneficial trial for future preparations of lubricating grease.

Graphical Abstract

Keywords:

• ZrP intercalation compounds
• grease thickeners
• rheology
• tribological properties

Acknowledgements

We thank International Science Editing (http://www.internationalscienceediting.com) for editing this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

We are thankful for the financial support provided from the National Natural Science Foundation of China (21978186, U21A20315, 21436008), the Fund for Shanxi “1331” Project and the Graduate Education Innovation Project of Shanxi Province (2022Y181).