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The SiO2 nanoparticles were synthesized with a ydrothermal method and modified by oleic acid. The tribological properties of the modified SiO2 nanoparticles as bricating oil additives are studied by friction test. It was found that the nanoparticles as additives in lubricant oil can effectively improve anti-friction and anti-wear roperties. The anti-friction and anti-wear mechanisms were discussed and the lubricating effect of SiO2 nanoparticles can be attributed to rolling effect and self-repairing effect of mechanism.

In this paper, the author does research on the surface modified of nanometer ZrO2/SiO2 composite and makes it a good dispersivity in organic solvents. As lubricating oil additive, added it into the base oil with different concentration. Anti-wear and reducing friction performances measured by the four ball test and the thrust-ring tribotester. The results showed that the average friction coefficient decreased 21.14%, the weight lost of the thrust-ring was no wear or negative wear when the additive concentration was 1wt%. The worn surfaces were quite different compared without additive, the grooves formed during the friction experiment become smooth and finally a narrow wear scar. There were many white particles and dimples on gray surface, the white particles were higher than those of gray parts. The white particles was ZrO2/SiO2 composites according to EDS and XRD analysis. The Si and Zr elements appeared on the worn surfaces can not be cleaned out in petroleum ether and ultrasonic ambiance, this is a dynamic self-healing mechanism .

Nano-ZrO2 particles were modified by KH-570 (γ-methacryloxypropyltrimethoxysilane). The nano-ZrO2 before and after modified were characterized by UV-VIS spectrophotometer and transmission electron microscopy (TEM). The anti-wear and friction reduction properties of nano-ZrO2 used as additive in lubrication were analyzed by friction and wear test machine of MMU-10G. The results show that the polarity of nano-ZrO2 after modified is changed, the surface free energy is reduced, and both the dispersity and stability of the modified nano-ZrO2 in organic media are improved. The modified nano-ZrO2 can increase the anti-wear and friction reduction properties of the base oil. Lubrications containing 0.10wt% and 0.05wt% nano-ZrO2 have the best tribological properties in the four-ball test and the thrust-ring test, respectively. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) was used to analyze the protective layer formed on the rubbed surface, and Zr elements were found on the rubbed surface.