Abstract: Using pyridinium dialkyl dithiophosphate (PyDDP) as the surface modifying agent, PyDDP surface modified nanolanthanum borate and nano-molybdenum disulfide were prepared respectively, and borate-molybdenum agent was formed based on the two components. Infrared spectrum (IR), Xray diffraction (XRD) and transmission electron microscope (TEM) were employed to analyze the structure of nano-particles. The results showed that borate-molybdenum agent was consisted of nano-lanthanum borate and nano-molybdenum disulfide particles, and the particle size was around 30nm to 50nm. The tribological properties of PyDDP surface modified borate molybdenum agent were evaluated with four-ball test methods. The surface micrograph and the elements compositions for the scar of experimental ball were tested with scanning electron Microscope (SEM), electron diffraction Xray analysis (EDXA) and X-ray photoelectron spectroscope (XPS). The results show that borate-molybdenum agent possesses better extreme-pressure properties, and the property improvement of borate-molybdenum agent is due to the formation of inorganic reaction membrane.

Key words: surface modification, borate-molybdenum agent, anti-wear reagent at extreme pressure, modification with tribological chemistry