Preparation of borate ester and evaluation of its tribological properties as an additive in different base oils

Abstract

N‐containing borate ester (MEBE) with five‐member ring structure as a lubricant additive was synthesised. The tribological properties in liquid paraffin (LP), poly‐alpha‐olefin (PAO) and dioctyl sebacate (DOS) were evaluated, and the action mechanisms in different base oils were also explored. It was found that as‐synthesised borate ester possesses excellent antiwear performance in LP and PAO. XPS analysis suggests that the additive forms a protective film on the rubbing surfaces which is composed of BN, Fe2O3, polyoxyethylene ether and N‐containing organic compounds. The inorganic and organic protective films in the metal surface effectively improve the antiwear ability of the base stock. However, when the additive MEBE was introducted into DOS base oil which is prone to adsorbing to the metal surface because of the high polarity of DOS, it influences the compactness of the film formed by the DOS, resulting in weak antiwear property. Copyright © 2016 John Wiley & Sons, Ltd.

Tribological characteristic and mechanism analysis of borate ester as a lubricant additive in different base oils

“…However, the WSD increases with further increase of additive concentration above 1.0%. Furthermore, compared with MEBE borate synthesized in the past, 25 the antiwear property of DEBE was superior to that of MEME at low additive concentration (less than 0.6% in LP). However, when the additive concentration was more than 0.6%, DEBE is lower in antiwear performance than MEBE.…”

“…4 depicts the relationship between friction coefficient and additive concentration in LP, PAO and DIOS base oils under the applied load of 200 N (corresponding to the maximum Hertz Contact Pressure is 2664 MPa). 25 It can be seen from the curves that the friction coefficient decreased slightly when DEBE borate ester was introduced into DIOS. And the friction coefficient sometimes was even a little higher than the one under the lubrication of LP alone, as the additive concentration in LP increased, Furthermore, under the same conditions, the friction coefficient of DEBE in liquid paraffin is lower than that of MEBE borate ester in liquid paraffin which is we synthesized in the past.…”

“…And the friction coefficient sometimes was even a little higher than the one under the lubrication of LP alone, as the additive concentration in LP increased, Furthermore, under the same conditions, the friction coefficient of DEBE in liquid paraffin is lower than that of MEBE borate ester in liquid paraffin which is we synthesized in the past. 25 However, the friction coefficient is low and almost unchanged with the increase additive concentration in PAO. In general, it was an interesting phenomenon that the friction coefficient did not change obviously compared with the base oils, which suggests that there is no high shearing strength component generated on the surface of the frictional pairs.…”

“…In our previous research, we have tried to synthesize an Ncontaining borate ester (MEBE) with ve-member ring structure. 25 In the present research, with the aim to improve the tribological performance and hydrolytic stability of lubricant, we select alkylphenol polyoxyethylene ether, boric acid and diethanolamine as staring materials without high price heterocyclic compounds to synthesize S-and P-free DEBE borate ester with double ve-member-ring structure. This article reports the details about the preparation and evaluation of the tribological properties in relation to worn surface analysis by scanning electron microscopy and X-ray photoelectron spectroscopy.…”

Tribological properties of lanthanum perrhenate as lubricating additive over a wide temperature range

“…In the carbon spectrum, the C1s peaks located at 283.72 eV and 284.75 eV were the main components and were attributed to C-C and C-O bonds of organic compounds, which suggested that the decomposition products of the base oil were adsorbed on the worn surface. 33 Another peak at 286.35 eV was assigned to the COO functional group from the additional surfactants. Moreover, environmental contamination during the sliding test or the addition of an impurity during the wireelectrode cutting process may have contributed to this peak.…”