Tribological properties of 2 novel Mo/B–based lubricant additives in polyalphaolefin

Abstract

Two kinds of Mo/B oleic diethanolamide derivatives (coded as YXM and YXB) were synthesised, and their tribological properties were evaluated using a 4‐ball machine. Results indicate that the 2 novel additives show excellent antiwear and extreme pressure properties. When 2.5 wt% YXM was added into the base oil, the wear scar diameter was reduced by 42.2%, and the PB value was increased by 170.4%; when 2.5 wt% YXB was added into the base oil, the wear scar diameter was reduced by 23.1%, and the PB value was increased by 167.1%. The worn surfaces of the lubricated GCr15 steel were analysed by using scanning electron microscopy and X‐ray photoelectron spectroscopy. It is indicated that the variation of tribofilm species produced by a chemical reaction between the additives and the steel surface plays an important role in inhibiting wear and friction. A model was used to analyse the action mechanism. According to the analysis, the tribofilm is composed of an adsorption layer and a reaction layer, and it could effectively protect the steel surfaces from direct contact.

Frictional evaluation of halogen-free ionic liquids with low corrosion degree and high decomposition temperature on steel surface

“…When the temperature reaches 376.8°C and 392.4°C, the weight loss of [MPBIM][BMB] is 10% and 50%. The analysis results imply that [OBIM][BMB] and [MPBIM][BMB] possess higher decomposition temperature than traditional organic borate additives (Wang et al , 2018; Huang et al , 2017).…”

“…The Fe2p peaks, located at 710.0, 711.4 and 724.1 eV, belong to FeO, Fe 2 O 3 and Fe 3 O 4 . The peak at 191.2 eV represents the B1s of B 2 O 3 (Huang et al , 2017). Combining with peaks of Fe2p and O1s, it can be found that the borate anions or the decomposed borate anions have reacted with the steel surface thereby forming the iron oxide compound.…”

“…The corresponding contents of the characteristic elements on the worn surface are listed at Table A2. As is shown in Table A2, (Huang et al, 2017). Combining with peaks of Fe2p and O1s, it can be found that the borate anions or the decomposed borate anions have reacted with the steel surface thereby forming the iron oxide compound.…”

“…The thermal stability of the oil depends on the composition of the base oil and the thermal stability of additives (Ning et al, 2015). Figure 1 (Wang et al, 2018;Huang et al, 2017). [BMB] decreased slightly.…”

Tribological properties of borate ionic liquids with low corrosion grade and excellent thermal stability in 500 N base oil

“…2 Ionic liquid is a salt which existing in liquid form below the 100 C. 3 Outstanding solubility, high ionic conductivity, high decomposed temperature and low flammability make ionic liquids widely applied in lubricants and other fields. [4][5][6][7][8][9][10][11] Until now, scientists have synthesised a large number of ionic liquid lubricating additives, many of which contain sulfur, phosphorus and halogen elements. [12][13][14][15][16] For instance, the scientists introduced fluorine into anions, which effectively enhanced the tribological properties of ionic liquids.…”