Tribological behavior of ammonium-based protic ionic liquid as lubricant additive

Abstract

In this study, the tribological behavior of an ammonium-based protic ionic liquid (PIL) as an additive in a base mineral oil (MO) is investigated on a steel-steel contact at room temperature and 100 °C. Tri-[bis(2-hydroxyethylammonium)] citrate (DCi) was synthesized in a simple and low-cost way, and the ionic structure of DCi was confirmed by proton nuclear magnetic resonance (1H NMR). The stability measurement of 1 wt% DCi to a MO was investigated, and the lubricating ability and anti-wear properties of DCi as an additive in MO were also examined using a custom-designed reciprocating ball-on-flat tribometer. Optical microscope and profilometry were used to obtain the worn morphology of the steel disks. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were carried out to investigate the wear mechanism and to analyze the surface interactions between the rubbing components. When 1 wt% DCi is added into the base MO, frictional performance is improved at both temperatures studied with a friction reduction of 29.0% and 35.5%, respectively. Moreover, the addition of 1 wt% DCi to MO reduced the wear volume 59.4% compared to the use of MO. An oxygen-richened tribolayer is confirmed by EDS on the disk surface when DCi was used as additive under 100 °C.

Applications of carbon quantum dots in lubricant additives: a review

“…A large number of studies have shown that the lubrication performances of PEGbased lubricating oils are highly dependent on the lubricant additives, in particular the friction-reducing and anti-wear additives. With the rapid development of science technology, PEG-based lubricating oils are hard-pressed to meet increasingly harsh lubrication requirements of modern mechanical equipment such as super-high and/or ultra-low temperatures, extreme pressure, and high vacuum conditions, considerably limiting the further development of PEG-based lubricating oils [146,147]. Nanomaterials as additives to promote the friction-reducing and anti-wear properties of PEG-based lubricating oils have been repeatedly confirmed in the literature [66].…”

Linking Molecular Structure and Lubrication Mechanisms in Tetraalkylammonium Orthoborate Ionic Liquids

“…Despite these promising results, the implementation of ILs in oil formulations has been constrained by four main issues: (i) their high cost; (ii) the corrosivity of most ILs, which derives from the sensitivity of halogenated ILs to moisture that can result in the release of toxic and corrosive halogen halides [49][50][51][52]; (iii) the limited solubility of the vast majority of ILs in hydrocarbon uids; and (iv) our limited understanding of the IL lubrication mechanism(s), which has hampered our ability of rationally designing task-speci c ILs [53]. The rst three issues have progressively been solved over the last decade with: (i) the recent synthesis of airstable, eco-friendly, protic ILs (PILs), whose ease of preparation can signi cantly lower costs [54,55]; (ii) the transition towards halogen-free ILs, which has drastically decreased corrosion problems [56-65]; and (iii) the synthesis of oil-soluble ILs [31,61,[66][67][68][69][70][71][72] and the development of polymer-encapsulated ILs [53]. Despite these remarkable advancements, the underpinning lubrication mechanism of ILs is still under debate.…”

Effect of functional groups on tribological properties of lubricants and mechanism investigation

“…Energy consumption owing to friction accounts for 23%, approximately 119 EJ, of global energy consumption [1,2]. In present industrialized nations, financial wastage brought by friction and wear is as high as about 6% of GDP [1,3].…”