Preparation of surface–modified lanthanum fluoride–graphene oxide nanohybrids and evaluation of their tribological properties as lubricant additive in liquid paraffin

Abstract

Oleic acid surface–modified Lanthanum trifluoride–graphene oxide (OA–LaF3–GO) nanohybrids were successfully prepared by surface modification technology. The morphology and phase structure of as-prepared samples were analyzed by means of X-ray diffraction and transmission electron microscopy, Fourier transform infrared spectrometry, Raman spectrometry and thermogravimetry. The results revealed that OA were bonded onto the surface of LaF3–GO nanohybrids. Subsequently, the tribological properties of OA–LaF3–GO nanohybrids as lubricant additive in liquid paraffin were evaluated with a four-ball machine, and the morphology and elemental composition of worn steel surfaces were examined on a scanning electron microscope with an energy dispersive spectrometer. Tribological results showed that OA–LaF3–GO nanohybrids had excellent friction reduction and antiwear ability at the loading of 0.5wt.% OA–LaF3–GO nanohybrids, compared to liquid paraffin alone. The results of energy dispersive spectrometer revealed that improved tribological properties resulted from OA–LaF3–GO could transfer to the rubbed steel surface and decompose to form protective layers, which help to improve tribological properties.