New Driving Unit for the Direct Measurement of Yield Stress with a Stress Controlled Rheometer

Shahnazian, Hamid; Odenbach, Stefan

doi:10.1515/arh-2008-0019

Cited by 4 publications

(5 citation statements)

References 5 publications

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“…Due to the low volume concentration of magnetic nanoparticles in the fluid P1 a saturation of the yield stress could be observed. The magnetoviscous effect measured for fluid P1 is up to 20 times stronger compared with commercial ferrofluids [16]. The reason here is also the 60 times stronger interaction of the nanoparticles in the fluid P1 (λ * = 178.18).…”

Section: Discussionmentioning

confidence: 73%

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Rheology of a ferrofluid based on nanodisc cobalt particles

Shahnazian

Graf

Borin

et al. 2009

J. Phys. D: Appl. Phys.

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Rheological investigations as well as theoretical studies on ferrofluids have shown strong field and shear dependent changes in viscosity, which are correlated with the formation of chain-like clusters of magnetic nanoparticles. Moreover, the formation of these clusters leads to the appearance of viscoelastic effects or other non-Newtonian features in ferrofluids in the presence of a magnetic field. Previous investigations were carried out with differently composed ferrofluids, all of them containing particles of nearly spherical shape, but differing in the size of the nanoparticles, the volume concentration and the magnetic material. In the work presented here a ferrofluid with non-spherical cobalt nanoparticles is used, to get more information about the influence of the shape of the nanoparticles on their interparticle interaction and the resulting rheological behaviour of the suspension. For the experiments an especially designed stress controlled rheometer has been used. Experiments on yield stress as well as measurements of the magnetoviscous effect have been performed for this ferrofluid with nanodisc particles for different magnetic field strengths. The results from the yield stress experiments have been compared with those achieved for a cobalt-based ferrofluid containing spherical nanoparticles.

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Section: Discussionmentioning

confidence: 73%

“…For the rheological investigations a specialized stress controlled rheometer has been used [12,16]. The shear cell of this rheometer is a cone-plate arrangement (with an opening angle of 3 • and a cone diameter of 76 mm) combined with a Couette region.…”

Section: Rheological Investigations Of Ferrofluids P1 and P2mentioning

confidence: 99%

Rheology of a ferrofluid based on nanodisc cobalt particles

Shahnazian

Graf

Borin

et al. 2009

J. Phys. D: Appl. Phys.

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“…To evaluate yield stress, the shear-stress-controlled experimental setup reported in [ 23 ] was used ( Figure 2 b). The measuring geometry of the system is a plate–plate configuration with an upper plate diameter of 76 mm.…”

Section: Methodsmentioning

confidence: 99%

“… Rheometric equipment: ( a ) shear rate and ( b ) shear-stress-controlled experimental setup. A detailed description and evaluation of the equipment is given in [ 1 , 23 ], respectively. …”

Section: Figurementioning

confidence: 99%

Magnetoviscosity of a Magnetic Fluid Based on Barium Hexaferrite Nanoplates

2021

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This paper presents the results of an experimental study of the influence of an external magnetic field on the shear flow behaviour of a magnetic fluid based on barium hexaferrite nanoplates. With the use of rheometry, the magnetoviscosity and field-dependent yield-stress in the fluid are evaluated. The observed fluid behaviour is compared to that of ferrofluids with magnetic nanoparticles having high dipole interaction. The results obtained supplement the so-far poorly studied topic of the influence of magnetic nanoparticles’ shape on magnetoviscous effects. It is concluded that the parameter determining the observed magnetoviscous effects in the fluid under study is the ratio V2/l3, where V is the volume of the nanoparticle and l is the size of the nanoparticle in the direction corresponding to its orientation in the externally applied magnetic field.

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“…As additional proof for the differences in structure formation in the samples investigated, yield stress measurements were carried out with a stress-controlled rheometer described in [24,25].…”

Section: Rheological Measurementsmentioning

confidence: 99%

Magnetic measurements on frozen ferrofluids as a method for estimating the magnetoviscous effect

Borin

Odenbach

2009

J. Phys.: Condens. Matter

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Magnetic measurements on frozen ferrofluids with and without significant structure formation in an applied magnetic field have been performed. The results of these investigations were compared with the magnetic field dependent rheological properties for two different kinds of ferrofluids. Magnetic experiments performed similarly to conventional field cooled-field warming magnetic tests show the contribution of magnetic domain blocking and structure reorganization to the rheology of ferrofluids. Our efforts have shown the possibility of giving an estimate of the magnetoviscous effect by considering the temperature dependence of the magnetization of a frozen sample.

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New Driving Unit for the Direct Measurement of Yield Stress with a Stress Controlled Rheometer

Cited by 4 publications

References 5 publications

Rheology of a ferrofluid based on nanodisc cobalt particles

Rheology of a ferrofluid based on nanodisc cobalt particles

Magnetoviscosity of a Magnetic Fluid Based on Barium Hexaferrite Nanoplates

Magnetic measurements on frozen ferrofluids as a method for estimating the magnetoviscous effect

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