Abstract: Electromagnetic effect generated by friction self on tribological properties of 150SN base oil and lubricating oils containing triethanolamine boric acid ester (TBE) was investigated by four ball tester. The morphologies of the worn surfaces and the chemical states of several typical elements on the worn surface were analyzed by means of scanning electronmicroscope (SEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectrometer (EDS). The tribological mechanisms by the physicochemical effects of electromagnetic field were discussed. The results indicated that under electromagnetic field, friction coefficients and wear scar diameters (WSDs) of steel balls lubricated by 150SN mineral oil was higher than those without electromagnetism impact. The WSDs of steel balls lubricated by triethanolamine (TBE)-doped oils under electromagnetic field were all smaller than those under non-magnetic field, but the friction coefficients were higher. It is inferred that a protective coat is formed on the frictional surface due to the effect of electromagnetic field on the interaction of elemental boron and nitrogen in TBE with metal interfaces, resulting in the formation of the film containing element boron and nitrogen through tribochemical reaction and the improvement of the tribological properties of lube oil containing TBE.

Key words: electromagnetic field, triethanolamine boric acid ester, tribochemistry, adsorbtive film, anti-wear additive