Development and performance of a magnetic ionic liquid for use in vacuum-compatible non-contact seals

Okabe, Takao; Moritaka, Daichi; Miyatake, Masaaki; Kondo, Yukishige; Sasaki, Shinya; Yoshimoto, Shigeka

doi:10.1016/j.precisioneng.2016.07.010

Cited by 7 publications

(3 citation statements)

References 13 publications

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“…As a combination of magnet and liquid, ferrofluids can be controlled by the magnetic field, which makes it become a promising candidate for many specific applications (Dailey et al, 1999;Hartshorne et al, 2004;Torres-Díaz and Rinaldi, 2014). The magnetic particles in ordinary ferrofluids are generally coated by a variety of long-chain organic surfactants (Hong et al, 2008;Okabe et al, 2017;Shi et al, 2018;Kumar et al, 2021;Kumar et al, 2022). These surfactants have a polar hydrophilic head group and an apolar hydrophobic end (Sawisai et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Colloidal Stability of Magnetite Nanoparticles Coated by Oleic Acid and 3-(N,N-Dimethylmyristylammonio)propanesulfonate in Solvents

2022

Front. Mater.

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In order to understand the factors affecting the colloidal stability in the carrier liquids of different ferrofluids, magnetite nanoparticles coated by surfactants 3-(N,N-dimethylmyristylammonio)propanesulfonate (DP) and oleic acid (OA) were fabricated as dispersions in diverse colloidal systems. The OA-coated magnetite could only be dispersed in the apolar carrier liquid (εr < 5), while DP-coated magnetite particles could establish a stable colloidal system in the polar base liquid (εr > 5) such as water and ethanol. The colloidal stability of OA-coated particles in the apolar solvents was mainly attributed to the steric repulsion of its outer thick liquid shell (∼3 nm). Due to the absence of steric repulsion on the solid thin shell (∼1 nm) on DP-coated magnetite, DP-coated particles could not be dispersed in the apolar liquid. In the polar liquid-based ferrofluids, DP-coated magnetite could form an electric double layer (EDL). The total Gibbs interfacial energy was analyzed based on Van Oss-Chaudhry-Good and DLVO theory to describe the behaviors of coated particles in solvents. In the case of neutral (pH = 7) water-based colloidal, DP-coated magnetite could establish an energy barrier of ∼2.2 kBT to prevent the particles from precipitation. Bare magnetite particles could form a relatively fragile colloid in a water system with an energy repulsion of ∼1.2 kBT. In contrast, OA-coated magnetite exhibited a severe phase separation in a water-based colloidal system due to its net attraction ∼ −1.3 kBT.

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Section: Introductionmentioning

confidence: 99%

Colloidal Stability of Magnetite Nanoparticles Coated by Oleic Acid and 3-(N,N-Dimethylmyristylammonio)propanesulfonate in Solvents

2022

Front. Mater.

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“…Lorentz body force encountered in magnetohydrodynamics can be simultaneously considered as a control mechanism with electro-osmotic body force and electrical double layer effects associated with electro-kinetics. Important studies in this regard include Bombard et al [39] in steel-polymeric point contact mechanics and Okabe et al [40] for vacuumcompatible non-contact seals. Of the rare investigations on EMHD squeezing flows, Thumma et al [41] employed a spectral local linearization method (SLLM) to simulate the unsteady magnetic ionic lubrication in squeezing flows with radiative flux in an electromagnetic actuator.…”

Section: Introductionmentioning

confidence: 99%

Electroosmotic modulated unsteady squeezing flow with temperature-dependent thermal conductivity, electric and magnetic field effects

Prakash¹,

Tripathi

Bég

et al. 2022

J. Phys.: Condens. Matter

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Modern lubrication systems are increasingly deploying smart (functional) materials. These respond to various external stimuli including electrical and magnetic fields, acoustics, light etc. Motivated by such developments, in the present article unsteady electro-magnetohydrodynamics (EMHD) squeezing flow and heat transfer in a smart ionic viscous fluid intercalated between parallel plates with zeta potential effects is examined. The proposed mathematical model of problem is formulated as a system of partial differential equations (continuity, momenta and energy). Viscous dissipation and variable thermal conductivity effects are included. Axial electrical distribution is also addressed. The governing equations are converted into ordinary differential equations via similarity transformations and then solved numerically with MATLAB software. The transport phenomena are scrutinized for both when the plates move apart or when they approach each other. Also, the impact of different parameters such squeezing number, variable thermal conductivity parameter, Prandtl number, Hartmann number, Eckert number, zeta potential parameter, electric field parameter and electroosmosis parameter on the axial velocity and fluid temperature are analyzed. For varied intensities of applied plate motion, the electro-viscous effects derived from electric double-capacity flow field distortions are thoroughly studied. It has been shown that the results from the current model differ significantly from those achieved by using a standard Poisson-Boltzmann equation model. Axial velocity acceleration is induced with negative squeeze number (plates approaching, S< 0) in comparison to that of positive squeeze number (plates separating, S>0). Velocity enhances with increasing electroosmosis parameter and zeta potential parameter. With rising values of zeta potential and electroosmosis parameter, there is a decrease in temperatures for U_e>0 for both approaching i. e. squeezing plates (S < 0) and separating (S >0) cases. The simulations provide novel insights into smart squeezing lubrication with thermal effects and also a solid benchmark for further computational fluid dynamics (CFD) investigations.

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“…On the other hand, traditional MFs require a large amount of surfactant to achieve dispersion in the base fluid, which means that they often exhibit poor stability as compared with MILs. Moreover, traditional MFs exhibit undesired volatility and phase separation, but MILs often possess excellent high temperature stability and low (no) vapor pressure [19,20]. Therefore, MILs as functionalized ionic liquids could be of special significance in tribology [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Effects of magnetic ionic liquid as a lubricant on the friction and wear behavior of a steel-steel sliding contact under elevated temperatures

et al. 2019

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A magnetic ionic liquid (abridged as MIL) [C 6 mim] 5 [Dy(SCN) 8 ] was prepared and used as the magnetic lubricant of a steel-steel sliding pair. The tribological properties of the as-prepared MIL were evaluated with a commercially obtained magnetic fluid lubricant (abridged as MF; the mixture of dioctyl sebacate and Fe 3 O 4 , denoted as DIOS-Fe 3 O 4 ) as a control. The lubrication mechanisms of the two types of magnetic lubricants were discussed in relation to worn surface analyses by SEM-EDS, XPS, and profilometry, as well as measurement of the electric contact resistance of the rubbed steel surfaces. The results revealed that the MIL exhibits better friction-reducing and antiwear performances than the as-received MF under varying test temperatures and loads. This is because the MIL participates in tribochemical reactions during the sliding process, and forms a boundary lubrication film composed of Dy 2 O 3 , FeS, FeSO 4 , nitrogen-containing organics, and thioether on the rubbed disk surface, thereby reducing the friction and wear of the frictional pair. However, the MF is unable to form a lubricating film on the surface of the rubbed steel at 25 °C , though it can form a boundary film consisting of Fe 3 O 4 and a small amount of organics under high temperature. Furthermore, the excessive Fe 3 O 4 particulates that accumulate in the sliding zone may lead to enhanced abrasive wear of the sliding pair.

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Development and performance of a magnetic ionic liquid for use in vacuum-compatible non-contact seals

Cited by 7 publications

References 13 publications

Colloidal Stability of Magnetite Nanoparticles Coated by Oleic Acid and 3-(N,N-Dimethylmyristylammonio)propanesulfonate in Solvents

Colloidal Stability of Magnetite Nanoparticles Coated by Oleic Acid and 3-(N,N-Dimethylmyristylammonio)propanesulfonate in Solvents

Electroosmotic modulated unsteady squeezing flow with temperature-dependent thermal conductivity, electric and magnetic field effects

Effects of magnetic ionic liquid as a lubricant on the friction and wear behavior of a steel-steel sliding contact under elevated temperatures

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