Novel N-containing heterocyclic borate ester with hydrolytic stability as lubricant additive

A new kind of N-containing heterocyclic borate ester (MTMDB) as lubricant additive was synthesized and characterized. The tribological behaviors of MTMDB and ZDDP in 100N base oil were evaluated through four-ball machine. The surface morphology of the worn surface lubricated by MTMDB was investigated by scanning electron microscope (SEM) and the tribological mechanisms were analyzed by energy dispersive spectrometer (EDS). The results show that the synthesized additive exhibits high hydrolytic stability, good anti-wear property and excellent extreme pressure performance. When 2.5% MTMDB was added into the 100N base oil, the smallest wear scar diameter (WSD) 0.48 mm is obtained. Furthermore, S and B elements were detected on the surface of the abraded steel. This can be confirmed that MTMDB has adsorbed and reacted with the steel surface during the rubbing process and generates a protective film.