Research on liquid lubricants for space mechanisms

Jones, William; Shogrin, Bradley A.; Jansen, Mark J.

doi:10.1002/jsl.3000170203

Cited by 40 publications

(28 citation statements)

References 6 publications

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“…13 Alkyl sulfate ionic liquids are very economical and have broad potential in their molecular design.…”

Section: -12mentioning

confidence: 99%

“…Friction force was monitored throughout the test and the data were converted to friction coefficient. Two tests were run for each set of test parameters, and differences in the results were less than 15%.Both imidazolium salts showed good lubricant properties that were lower than those from perfluoropolyether (PFPE), 13 which is widely used as a lubricant for head/disk interfaces or micromachines. However, a significant weak point was found…”

mentioning

confidence: 99%

“…Both imidazolium salts showed good lubricant properties that were lower than those from perfluoropolyether (PFPE), 13 which is widely used as a lubricant for head/disk interfaces or micromachines. However, a significant weak point was found…”

mentioning

confidence: 99%

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Design of Alkyl Sulfate Ionic Liquids for Lubricants

Itoh¹,

Watanabe

Inada

et al. 2008

Chemistry Letters

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Tribological properties of alkyl sulfate ionic liquids have been evaluated; hydrophobicity of ionic liquids significantly influenced the tribological characteristics and combination of phosphonium cation with hydrophobic octafluoropentyl sulfate anion afforded good ionic liquid that showed excellent tribological performance.Ionic liquids (ILs) are a new class of fluids and interest has been growing in their application in diverse fields of science and technology.1,2 The tribological properties of ionic liquids have attracted increased attention in recent years since Liu and coworkers 3a first reported the possible use of these compounds as a lubricant, because of their low volatility and flammability. [3][4][5][6][7][8][9][10][11][12] ILs generally show outstanding thermo-oxidative stability, this property being particularly important for lubricants that are used under extreme conditions. 13Alkyl sulfate ionic liquids are very economical and have broad potential in their molecular design.2c However, little attention has been given to their application as lubricant to date. We recently reported the successful design of hydrophobic alkyl sulfate ionic liquids using fluorine chemistry; 2e the hydrophobicity of alkyl sulfate imidazolium salts was dependent on the content ratio of the fluorine to the alkyl sulfate anion and 2,2,3,3,4,4,5,5-octafluoropentyl sulfate (C5F8) imidazolium salt showed perfect hydrophobic properties, 2e while non-fluorinated pentyl sulfate (C5F0) salt showed a strong hydrophilic nature. 2c,2e In this paper, we report the results of evaluation of alkyl sulfate ionic liquids as lubricants.Tribological properties for our three types of original ionic liquids, i.e. 1-butyl-3-methylimidazolium pentyl sulfate was 25 Â 7 mm made of SUJ2 steel (JIS). Friction force was monitored throughout the test and the data were converted to friction coefficient. Two tests were run for each set of test parameters, and differences in the results were less than 15%.Both imidazolium salts showed good lubricant properties that were lower than those from perfluoropolyether (PFPE), 13 which is widely used as a lubricant for head/disk interfaces or micromachines. However, a significant weak point was foundwas not constant during the experiments, it initially increased and then decreased with rubbing ( Figure 1). It was assumed that the friction became constant after 1000 s. owing to the reduced contact pressure by wear.On the contrary, no fluctuation of the friction coefficient was observed for [bmim][C5F8] (Figure 2). Since [bmim][C5F8] has perfect hydrophobic properties, no rust was found on the surface of the ball and disk; this provides a constant friction coefficient. The results suggest that hydrophobic ionic liquid is appropriate as a lubricant.It has been pointed out that reaction of iron metal with phosphorous forms a stable boundary film composed of iron phosphate and this generally contributes to an improvement in tribological properties.4 Therefore, we next tested ionic liquid2g as a lubricant under the sa...

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“…13 Alkyl sulfate ionic liquids are very economical and have broad potential in their molecular design.…”

Section: -12mentioning

confidence: 99%

mentioning

confidence: 99%

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Design of Alkyl Sulfate Ionic Liquids for Lubricants

Itoh¹,

Watanabe

Inada

et al. 2008

Chemistry Letters

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“…For example, PFPAEs have excellent viscosity, thermal stability, and low volatility, but they are susceptible to catalytic degradation on metal surfaces and tend to cause metal fluoride corrosion [7][8][9][10][11]. On the other hand, the mineral oils have high vapor pressure at high temperature [5,7].…”

Section: Introductionmentioning

confidence: 99%

“…Base oils for space application in the past include polyol esters, superrefined mineral oils, polyalphaolefines (PAOs), and perfluoropolyalkylethers (PFPAEs). However, these liquid lubricants have disadvantages that can limit their lifetimes in a vacuum environment [7]. For example, PFPAEs have excellent viscosity, thermal stability, and low volatility, but they are susceptible to catalytic degradation on metal surfaces and tend to cause metal fluoride corrosion [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Effect of ZrO2 Nanoparticles Additive on the Tribological Behavior of Multialkylated Cyclopentanes

Bai

2009

Tribol Lett

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Monodisperse ZrO 2 nanoparticles with a particle size of about 6-7 nm and low volatile multialkylated cyclopentanes (MACs) lubricant were prepared and characterized. The effect of ZrO 2 nanoparticles as additive on the friction and wear behavior of MACs base oil was investigated. The friction and wear performance of 2 wt% ZrO 2 nanoparticles ? MACs was evaluated using an Optimal SRV oscillating friction and wear tester, with a steel ball sliding against the same steel counterpart disc. Results indicate that the wear resistance and load-carrying capacity of MACs base oil were markedly raised and its friction coefficient changed little when 2 wt% ZrO 2 nanoparticles were added to it.

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Tribological investigations of ionic liquids in ultra‐high vacuum environment

Totolin

Conte

Berriozabal

et al. 2013

Lubrication Science

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A tribological investigation of two ionic liquids (ILs) that could be used as potential lubricants for vacuum or space applications is presented. Their tribological behaviour was evaluated using a ball-on-flat oscillating reciprocating motion CaTri ultra-high vacuum (UHV) tribometer and the results were compared against those of a conventional perfluoropolyether (PFPE) vacuum lubricant. The thermal stability of the lubricants was investigated by thermogravimetric analysis before exposing them to UHV environment. The worn steel surfaces were studied by X-ray photoelectron spectroscopy, optical and confocal microscope as well as scanning electron microscope. The tribological evaluations showed that ILs exhibited better friction reduction and anti-wear properties than the PFPE lubricant. The excellent tribological properties were attributed to the formation of a surface protective film composed of iron fluoride and iron phosphate, respectively, on the lubricated metal surfaces by a tribochemical reaction with the ILs.

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Research on liquid lubricants for space mechanisms

Cited by 40 publications

References 6 publications

Design of Alkyl Sulfate Ionic Liquids for Lubricants

Design of Alkyl Sulfate Ionic Liquids for Lubricants

Effect of ZrO2 Nanoparticles Additive on the Tribological Behavior of Multialkylated Cyclopentanes

Tribological investigations of ionic liquids in ultra‐high vacuum environment

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