The Chemical Preparation And Tribological And Self-repairing Property Evaluation Of TiO₂ Nanoparticles

Wearing resistance extensively exists in the actual production and our life. All machinery motion is relative movement relying on its` sliding couple. Abrasion happened with relative movement, and abrasion is the main cause of surface damage, spares invalid, and material loss. Wear not only consumes the enery and materials and decreases the equipment efficiency, but also accelerates the equipments discard and causes the parts replacement frequently and big economy loss. Therefore, abrasion is causing more and more extensive academic attention of many field. One of the important step of decreasing abrasion is lubracation, and the old lubrication oils only reduce the friction and wear function of the machines and equipment are developed in the direction of high speed, high load and high precision. The problem of how to improve the tribological properties of materials and the lubrication state of machine parts for prolonging their lifetime are becoming more and more attractive to improve attractive to all tribologists. The addition of various additives into lubricating oils is an important way to improve their lubrication properties, whereas, the application of surface treatments on materials is the effective methed for improving the friction and wear properties of machine parts.Nano-materials show broad application due to its unique physical and chemcial characteristics in the field of tribology, and become potential lubricating oil additives. Despite the present research still in the initial stage, many problems require to be solved, however, lots of experimental results indicate that nano-materials possess the characteristics of reducing wear, antiwear and extreme pressure.In this thesis, stearic acid and PEG 400 modified nanoparticles of anatase and rutile were prepared. Transimission electron microscope (TME),X-ray powder diffraction spectroscopy (XRD) and Thermogravimetric Analysis (TGA) were used to characterize the morphologics and structures of these surface-modified nanoparticles.All these prepared nanoparticles were used as additives in lubricating oil liquid paraffin and their tribological properties and self-repairing for the sliding couple were evaluated on a four-ball machine and HQ-1 machine.The following main conclusions were reached:1 The stearic acid and PEG 400 modified nanoparticles of anatase and rutile as additives in lubricating oil show good tribological properties. And rutile nanoparticles is better than anatase nanoparticles.2 Both of the stearic acid and PEG 400 modified nanoparticles of anatase and rutile as additives in lubricating oil can aslo repair the sliding couple. But their self-repairing mechanisms are different.