Ionic Liquids in Surface Protection

Arias‐Pardilla, J.; Espinosa, Tulia; Bermúdez, Marı́a-Dolores

doi:10.1007/978-3-319-15132-8_19

Cited by 13 publications

(13 citation statements)

References 92 publications

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“…Ionic liquids that include elemental fluorine exhibit low friction at steel/steel contacts due to the generation of ferrous fluoride. However, severe corrosion occurs on the worn surface, and hazardous hydrogen fluorine is produced through reaction with moisture [12][13][14]. This corrosion can be prevented with the use of ionic liquids under inert atmosphere, but the corrosion may occur after the atmospheric relief [15].…”

Section: Introductionmentioning

confidence: 99%

Lubricating Properties of Cyano-Based Ionic Liquids against Tetrahedral Amorphous Carbon Film

et al. 2020

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Ionic liquids have unique characteristics, which render them ideal candidates as new base oils or additives. In particular, there are great expectations from the combination of diamond-like carbon and cyano-based ionic liquids. Lubricating properties of cyano-based ionic liquids have been studied on specific tetrahedral amorphous carbon (ta-C) films. After lubrication, ta-C film/ta-C film contact interface exhibits exceedingly low friction. Therefore, it is necessary to understand this low friction phenomenon. The current study evaluated the lubricating mechanism of cyano-based ionic liquids against ta-C films. 1-Butyl-3-methylimidazolium dicyanamide ((BMIM)(DCN)) and 1-butyl-3-methylimidazolium tricyanomethane ((BMIM)(TCC)) were used as lubricants, with the latter exhibiting low friction coefficient of 0.03. Steel cylinders and disks with ta-C films were used as test specimens. Raman spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and thermogravimetric analysis (TGA) helped us understand the mechanism of low friction induced by (BMIM)(TCC). Graphitization of the ta-C film at high temperatures might have caused the reduction in friction between the films. Similarly, anion adsorption on the worn surface at high temperatures also led to reduced friction. However, the TGA result showed a different trend than that of the sliding test. Our results indicate that the cyano-based ionic liquids underwent tribo-decomposition at low temperatures. Further, a minimum temperature was required for the adsorption of anions onto the sliding surface.

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Section: Introductionmentioning

confidence: 99%

Lubricating Properties of Cyano-Based Ionic Liquids against Tetrahedral Amorphous Carbon Film

et al. 2020

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“…However, use of fluorine-based ionic liquids as a lubricant results in corrosion of metallic materials due to the formation of hydrogen fluoride [8,24]. Especially, tetrafluoroborate and hexafluorophosphate undergo hydrolysis when exposed to moisture and generate hydrogen fluoride even without sliding [25][26][27]. To prevent corrosion, use of fluorinefree ionic liquids, such as bis(oxalato)borate, ethylsulfate, diethylphosphate, dicyandiamide, tricyanomethane, and tetracyanoborate has been explored [28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Tribological Properties of Cyano-Based Ionic Liquids under Different Environments

Kawada

Sasaki

2018

Tribology Online

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Ionic liquids have been used as novel high-performance lubricants. However, fluorine-based ionic liquids cause corrosion of materials by the formation of FeF 2 and FeF 3 . This study focuses on cyano-based ionic liquids, as they have low corrosion tendencies owing to the absence of fluorine in their structures. However, cyano-based ionic liquids are hydrophilic, and hence, the effect of ambient conditions (e.g., atmospheric moisture) on the tribological properties needs to be investigated. This study reports the tribological properties of two types of cyano-based ionic liquids 1-ethyl-3-methylimidazolium dicyanamide and 1-ethyl-3-methylimidazolium tricyanomethane under air, vacuum, and dry air environments. Their friction coefficients were found to be dependent on the ambient condition. Both the ionic liquids exhibited low friction coefficients in vacuum. The time-of-flight secondary ion mass spectrometry results indicated that the anion was adsorbed on the worn surface under vacuum conditions, and the adsorbed anion exhibited a low friction. In dry air, the cation was adsorbed on the worn surface, and the adsorbed cation exhibited a higher friction coefficient than the adsorbed anion. In air, the cyano-based ionic liquids caused corrosion of the sliding material and exhibited a high friction coefficient, because of the absorption of moisture from air.

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“…Room-temperature ionic liquids (ILs) are salt structures consisting of large cation and anion moieties, which are characterized by melting temperatures below 100 • C. In tribological applications, ILs have demonstrated superior performance as lubricants under both mixed and boundary conditions [1][2][3][4][5][6][7][8][9]. In severe environments, in space and at high temperatures, IL-base lubricants are especially propitious due to their exceptional thermal stability, both oxidative and nonoxidative [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…In severe environments, in space and at high temperatures, IL-base lubricants are especially propitious due to their exceptional thermal stability, both oxidative and nonoxidative [10][11][12][13][14]. During the last decade, imidazolium-base ionic liquids with fluorinated anions have been specially addressed in a number of studies [1,[15][16][17]. The application range of the imidazolium ILs was further expanded by rational designing of the molecular structure and the side chains offering the possibility of obtaining versatile ILs with tailored polarity, hydrophobicity, and corrosive and antioxidant properties [7,[18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Characterization of Dynamic Tribochemical Processes for Dicationic Imidazolium Ionic Liquid

et al. 2017

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Dynamic tribochemical processes for dicationic ionic liquid containing a geminal imidazolium cation head group bridged by a poly(ethylene glycol) and a bis(trifluoromethylsulfonyl)imide anion were studied using time-resolved mechanically stimulated gas emission mass-spectrometry (MSGE-MS). In comparison with similar monocationic imidazolium ionic liquids with short alkyl or long polyether side chains, the dicationic ionic liquid had a lower coefficient of friction on Ti6Al4V alloy and smoother behavior. The analysis of volatile decomposition products suggested multiple tribochemical reactions in which both anionic and cationic moieties are involved. The tribochemical degradation of cations was mainly through the detachment of the side and bridging chains from the imidazolium head groups. The absence of volatile products containing nitrogen implies that the imidazole group remained unchanged. Hydrogen and water desorption were attributed to the reactions of hydrogen fluoride being a product of anion degradation with titanium and titanium oxide, respectively.

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Ionic Liquids in Surface Protection

Cited by 13 publications

References 92 publications

Lubricating Properties of Cyano-Based Ionic Liquids against Tetrahedral Amorphous Carbon Film

Lubricating Properties of Cyano-Based Ionic Liquids against Tetrahedral Amorphous Carbon Film

Tribological Properties of Cyano-Based Ionic Liquids under Different Environments

Time-Resolved Characterization of Dynamic Tribochemical Processes for Dicationic Imidazolium Ionic Liquid

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