Effectiveness of phosphonium cation-based ionic liquids as lubricant additive

Abstract

Two phosphonium cation-based ionic liquids (ILs) were studied as additive to a mineral oil. Solubility tests and TGA of neat samples were performed. Three concentrations of the ILs were used in the tribological tests. Base oil-ZDDP mixtures were used as comparison samples. Tribological tests were made using a reciprocating ball-on-disc configuration. Load ramp and Stribeck curve tests were also performed. The worn surface was studied by different techniques. The results showed similar and better friction reduction properties for ILs-or ZDDP-containing mixtures than the neat base oil. The [P 66614 ][(iC8) 2 PO 2 ] -containing mixtures outperformed the antiwear behavior of the other samples. XPS results showed different mechanisms of lubrication when using ILs or ZDDP.

The Lubrication Ability of Ionic Liquids as Additives for Wind Turbine Gearboxes Oils

“…(Figure 5b). It has been reported [12][13][14][15][16][17][18][19][20][21] that ILs have the ability to form highly ordered absorbed layers on metal surfaces. This layer prevents direct contact between mating surfaces, reducing friction and wear.…”

“…However, halogen-containing anions are very sensitive to moisture and, in the presence of water, will react, causing: (1) the corrosion of metallic surfaces by formation of metallic halides and (2) the evolution of toxic species (HF) from hydrolysis of the anions [17,18]. Recent literature has suggested the potential of using ILs with halogen-free anions [11,19,20]; however, studies on the tribological performance of these ILs as additives of lubricants for wind turbine applications are still very scarce.…”

Isoconversional kinetic analysis applied to five phosphonium cation-based ionic liquids

“…This fact provoked the introduction of new and more stable ILs based on [FAP] and [NTf 2 ] anions [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53], which present enhanced tribological properties due to the formation of fluoride tribofilms, especially at high loads [54]. Recently, phosphonium cation-based ILs have been introduced in this field because of their growing commercial availability and good tribological performance [26,[55][56][57][58][59][60][61][62]. Finally, taking into account the importance of thermal stability in the lifetime of lubricants and additives, the determination of thermal models has become an interesting research topic from scientific and technical points of view.…”

Corrosion activity and solubility in polar oils of three bis(trifluoromethylsulfonyl) imide/bis(trifluoromethylsulfonyl) amide ([NTF 2 ]) anion-based ionic liquids

“…The inherent low solubility of the ILs in non-polar hydrocarbon oils has generated many researches [16,[28][29][30][31][32], where the ILs were used in oil-IL emulsions or as lubricant additives in low concentration. Since 1 Although commonly referred to it as "imide" in tribology, IUPAC recommendations suggest the name bis(trifluoromethylsulfonyl)amide [1] 2009, the potential applications of phosphonium-cation-based ILs have been studied [33,34].…”

“…Since 1 Although commonly referred to it as "imide" in tribology, IUPAC recommendations suggest the name bis(trifluoromethylsulfonyl)amide [1] 2009, the potential applications of phosphonium-cation-based ILs have been studied [33,34]. Some of these ILs have drawn attention due to their solubility in non-polar oils and performance as lubricant additives [31][32][33][34][35]. These findings are interesting and the adsorption of the ILs on the surfaces due to their polar character can be used effectively in thin film lubrication.…”