Rheological Properties and Stabilization of Magnetorheological Fluids in a Water-in-Oil Emulsion

Park, Jae Hyung; Chin, Byung Doo; Park, O Ok

doi:10.1006/jcis.2001.7622

Cited by 120 publications

(61 citation statements)

References 12 publications

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“…However, specific properties of MRF such as shear and yield stresses under the same conditions were enormously degraded inevitably by addition of the coating layer. This is due to the shielding of the polymer layer that affects the magnetic properties of the particles [19,20]. In addition, some additives can improve the secondary properties like oxidation stability or abrasion resistance.…”

Section: Composition Of Mrfmentioning

confidence: 99%

Optimal Design Methodology of Magnetorheological Fluid Based Mechanisms

Nguyen¹,

Choi²

2012

Smart Actuation and Sensing Systems - Recent Advances and Future Challenges

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Section: Composition Of Mrfmentioning

confidence: 99%

Optimal Design Methodology of Magnetorheological Fluid Based Mechanisms

Nguyen¹,

Choi²

2012

Smart Actuation and Sensing Systems - Recent Advances and Future Challenges

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“…The response is maximized for sufficiently high particle concentrations, and this may require solids contents as high as 30% v/v. The typically use of organic media, surface modifier, or nonmagnetic nanoparticles [23][24][25][26][27][28][29] could improve the stability of the fluid but also have the disadvantages of the increased viscosity of the system and thus could hinder the magnetorheological effect. In some cases the organic media have no surface charge and hence there is no electrostatic repulsion between particles, which could prevent their irreversible aggregation induced by van der Waals and magnetic (due to the remnant magnetization) interactions.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Nanoparticles as a Redispersing Additive in Magnetorheological Fluid

Portillo

Iglesias

2017

Journal of Nanomaterials

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Unwanted agglomeration of micro particles in magnetorheological fluid is an important problem for many technological applications. Furthermore, the stability of this kind of fluid is also studied as an important property in many research papers. Prior to use, a redispersion of agglomerated or aggregated (connected by solid phase) particles is often necessary. The objective of this study is to evaluate the dispersibility effect of magnetic nanoparticles as a carrier, while keeping the magnetorheological (MR) effect as high as possible. A simple device based on the estimation of the penetration force of a standard needle is presented. The needle moves across the sample vertically with a constant velocity and it is attached to a scale which registers the force displaced by the needle during the dynamic test. The effect with and without other additives was also studied. Transmission electron microscopy (TEM) and Scanning Electron Microscopy (SEM) reveal a protective behavior of nanoparticles around the micro particles. We conclude that addition of magnetic nanoparticles improves the dispersibility characteristic compared with common dispersing additives without affecting the MR effect.

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“…Also, the carrier fluids, although typically silicon or petroleum oils or other non-polar liquids [15][16][17][18], have been studied to a large extent [8], including ionic liquids [19][20][21][22], aqueous media [23,24] or even ferrofluids [4].…”

Section: Introductionmentioning

confidence: 99%

“…These include typically organic molecules in solution or adsorbed on the particles [8,23,[42][43][44][45], but the use of ionic liquids [21,22,46,47] or suspensions of nanoparticles (either magnetic or not) [4,[48][49][50][51] as carriers has also proven rather efficient in opposing aggregation and sedimentation on MRFs.…”

Section: Introductionmentioning

confidence: 99%

Dynamic and wear study of an extremely bidisperse magnetorheological fluid

Iglesias¹,

Ruiz-Morón²,

Durán³

et al. 2015

Smart Mater. Struct.

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HIGHLIGHTSFive magnetorheological fluids are tested for MR response, and wear and friction A standard four-ball method is used for wear testingThe bimodal (with a magnetite ferrofluid as base liquid) fluid displays the best MR performance both before and after testing Steel scratches are observed in fluids containing the iron particles in base oil, the effect being more important in absence of anti-wear additiveThe bimodal fluid produces a milder wear, at the price of a larger friction coefficient ABSTRACTIn this work the friction and wear properties of five magnetorheological (MR) fluids with varying compositions are investigated. Considering that many of the proposed applications for these fluids involve lubricated contact between mobile metal-metal or polymer-metal parts, the relationship between MR response and wear behavior appears of fundamental importance. One of the fluids (MR#1) contains only the iron microparticles and the base oil; the second and third ones (MR#2 and MR#3) contain an anti-wear additive as well. The fourth one (MR#4) is a well know commercial MR fluid. Finally, MR#5 is stabilized by dispersing the iron particles in a magnetite ferrofluid. The MR response of the latter fluid is better (higher yield stress and postyield viscosity) than that of the others. More important, it remains (and even improves) after the wear test: the pressure applied in the four-ball apparatus produces a compaction of the magnetite layer around the iron microparticles. Additionally, the friction coefficient is larger, which seems paradoxical in principle, but can be explained by considering the stability of MR#5 in comparison to the other four MRs, which appear to undergo partial phase separation during the test. In fact, electron and optical microscope observations confirm a milder wear effect of MR#5, with almost complete absence of scars from the steel test spheres and homogeneous and shallow 3 grooves on them. Comparatively, MR#2, MR#3 and, particularly, MR#1 produce a much more significant wear.

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Rheological Properties and Stabilization of Magnetorheological Fluids in a Water-in-Oil Emulsion

Cited by 120 publications

References 12 publications

Optimal Design Methodology of Magnetorheological Fluid Based Mechanisms

Optimal Design Methodology of Magnetorheological Fluid Based Mechanisms

Magnetic Nanoparticles as a Redispersing Additive in Magnetorheological Fluid

Dynamic and wear study of an extremely bidisperse magnetorheological fluid

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