Synthesis And Surface Modification Of The Nanoscale Cerium Borate As Lubricant Additive

Lubricant additives which can determine the scope, the horizontal and the life of lubricating oil, is an important part of lubrication oil. With the consideration of the environmental pollutions, attentions have been paid to the Environment-friendly lubricants. Recently, lubricant additives containing boron element have been given more addition, during to its low impact to the environment and ecology.In this experiment, nanoparticle of cerium borate was synthesized via sol-gel precipitation method under micro-emulsion by oleic acid (OA), which can present the further reunion in the synthesis stage. The morphology and microstructure of as-prepared particles have been characterized by means of scanning electron microscope (SEM), X-ray diffraction (XRD), infrared spectroscopy (IR), and thermogravimetric analysis (TGA). The IR and TGA spectra show OA was not simply physical absorbed on the surface of nanoparticles but chemical bonded to the surface of synthesized nanoparticles. In order to get the small and uniform particles, we examined the factors affecting the reaction, including reaction temperature, reaction time, dispersing agent, ratio of raw materials, etc. The nanoscale surface modified cerium borate with a size of about 50nm can be synthesized in the temperature range 70 to 75°C for two hours, with the concentration of cerium nitrate and borax being 0.131mol/L, 0.0414 mol/L respectively. In this investigation, the synthesized cerium borate particles were dispersed in base oil by two different methods. In order to get the stability of lubricant additives in oil, we examine the transparency of lubricating oil and the actual concentration of as-obtained particles in lubricating oil. The results including friction coefficient and wear scar diameter derived from the four-ball tribotester were used to compare the properties between laboratory allocation lubricants and industrial lubricants. The results of friction tests show that nanoscale modified cerium borate as lubrication additives would be promising in the future, but comparing to the industrial lubricants, there are still a wide gap.