Preparation and tribological properties of nanoaluminium fluoride as additives to base oil

Cubical AlF₃ nanoparticles have been successfully synthesised by immersing Ti₃AlC₂ powders in hydrofluoric acid-assisted solvothermal reaction. The as-prepared products are characterised by an X-ray diffractometer and scanning electron microscopy. The results showed that the AlF₃ nanoparticles have a cubical structure and the sizes of nanoparticles are about 100 nm in side length. The tribological properties of cubical AlF₃ nanoparticles as a lubrication additive in 100SN base oil were investigated by a UMT-2 ball-on-disc friction and wear tester. The wear scars were measured by a common optical microscope. The results show that under determinate conditions, the friction coefficient of the base oil containing AlF₃ nanoparticles is lower than that of pure base oil, and the base oil containing 1 wt% AlF₃ samples presented good tribological performance under the load of 15 N. The formation of tribofilm on the rubbing surface could explain the good friction of AlF₃ nanoparticles as additives.