Preparation and tribological properties of tetrafluorobenzoic acid-modified TiO2 nanoparticles as lubricant additives

A tetrafluorobenzoic acid-modified TiO2 nanoparticles with average diameter of 40 nm were chemically synthesized. The nanoparticles were amorphous and had good thermal stability. The nanoparticles were characterized by transmission electron microscope, Fourier transformation infrared ray, X-ray Diffraction, and their thermal stability was investigated by means of TGA and differential thermal analysis. The tribological properties of the FA–TiO2 nanoparticles as additive to liquid paraffin were evaluated with a four-ball tester. The morphologies on the worn surfaces of the lubricated GCr15 steel were studied using scanning electron microscope. The results show that the FA–TiO2 nanoparticles exhibit good performance in wear and friction reduction. The antiwear and load capability of liquid paraffin increased and the wear scar diameter strikingly deceased after adding nanometer TiO2.