New types of borate esters ocntaining nitrogen as lubricant additives: hydrolytic stability,friction educting and anti-wear properties

摘要

New types of borate esters have been synthesized as lubricant additives.Since a stable six-member ring of B with N ocrrdination has been formed in the molecule of novel borate esters,it exhibits higher hydrolytic stability.Its friction-reducing and anti-wear properties were measrued with a ball on-disk and four-ball friction and wear testers.These experiments indicated that their frication coefficient prevalently decrease about 20-30 percent than that of base oil andf the relevant wear diminished appaently.Furthermore,the performance is better than zinc dialkyldithiophosphorate (ZDDP) on certain ocnditions.Synergistic efect between borate esters and ZDDp is also found.Surface chemicstry of tribochemical film analysis by X-ray photoelectron spectroscope (XPS) indicated that three were adsrobed borate esters and B_2O_3 on the rubbing surface.Moreover,boron nitride was also detected.