Preparation and Tribological Properties of Lanthanum Trifluoride Nanoparticles-Decorated Graphene Oxide Nanosheets

Abstract

Graphene oxide (GO) nanosheets were decorated with lanthanum trifluoride (LaF3) nanoparticles by a simple solution method to afford LaF3–GO nanohybrids, with which ammonium fluoride and lanthanum nitrate were used as raw materials to synthesize LaF3 nanoparticles. As-prepared LaF3–GO nanohybrids were characterized by X-ray diffraction, Raman spectrometry, transmission electron microscopy, and Fourier transform infrared spectrometry. Moreover, the thermal stability of the as-prepared LaF3–GO nanohybrids was evaluated by thermogravimetric analysis, and their tribological properties as an additive of distilled water were evaluated with a four-ball friction and wear tester. It was found that LaF3 nanoparticles are integrated with the GO nanosheets through electrostatic interaction thereby affording LaF3–GO nanohybrids. In addition, when the as-prepared LaF3–GO nanohybrid was added into distilled water at an optimum mass fraction of 1.5%, it was able to significantly improve the tribological properties of distilled water. This is because LaF3–GO nanohybrids can be deposited on rubbed steel surfaces to form protective and lubricious layers consisting of GO, LaF3, Fe2O3, and FeF3, thereby significantly reducing the friction and wear of the steel–steel contact under water lubrication.