The Synergistic Effect Of N-containing Borate Ester And Phosphate Ester On Tribological Perfoemances

With the development of economy and society,the environmental problem has become more and more serious and the traditional additives of phosphate ester can hardly meet the environmental requirements.Because of its less ash and non-toxic,N-containing borate esters have been one of the most important researching directions in lubrication area.Besides,one of the important ways to update the lubricants is compounding with additives.In this article,based on the molecular design,two novel N-containing borate esters had been synthetic.And the tribological properties were evaluated by a four-ball tester.After compounded with two traditional phosphate esters,the compatibility performance of phosphate esters and N-containing borate esters was discussed.The scanning electron microscopy(SEM)was used to observe the worm surface of steel balls.And the thermal films and tribofilms generated by lubricates were explored by the X-ray absorption near-edge structure spectroscopy(XANES).The main content and results can be concluded as below:1.Synthesize two N-containing borate estersThe two N-containing borate esters show good anti-wear properties,and TSOBT shows better anti-wear performance in high load.When the load is low,the two additives show good friction-reducing property.ODDB shows better extreme pressure property.The B K-edge XANES spectra analysis showed the boron exist as the form of boron oxide.2.Study the interaction of phosphate esters and two N-containing borate estersThe combination of ODDB-TCP/TBP and TSOBT-TCP/TBP exhibit good anti-wear and friction-reducing properties when they are in a balance in quantity,which means N-containing borate esters and phosphate esters have excellent synergistic effect.And they have worse extreme pressure property than phosphate esters but it can meet general working condition.The main existence form of phosphorus in the boundary film is phosphate and the main existence form of sulfur is sulfate.It can be considered that in the process of friction,the additives which were adsorbed on the friction surface involves chemical reactions and produced inorganic salt,formed the boundary film and improve the anti-friction and anti-wear properties of lubricating oil.