Rheological response of soft flake-shaped carbonyl iron water-based MR fluid containing iron nanopowder with hydrophilic carbon shell

Autor: Chiranjit Sarkar, Chandra Shekhar Maurya
Rok vydání: 2021
Předmět:
Zdroj: Rheologica Acta. 60:277-290
ISSN: 1435-1528
0035-4511
DOI: 10.1007/s00397-021-01268-2
Popis: In this work, the rheological response and sedimentation stability of micron-sized flake-shaped carbonyl iron (CI) water-based magnetorheological (MR) fluid were investigated using iron nanopowder with hydrophilic carbon shell as an additive. The rheological behaviors of MR fluid containing 1 wt% iron nanopowder were measured with and without a magnetic field under shear rate, shear strain, and shear stress sweep mode using a parallel plate rotational rheometer. The magnetic field strength was varied from 0 to 131 kA/m, and in the presence of magnetic field strength, micron flake-shaped CI and iron nanopowder particles lead to form a robust columnar structure. It was observed that using 1 wt% of iron nanopowder with hydrophilic carbon shell, the rheological responses and sedimentation stability of MR suspension were enhanced. We fitted the shear stress as a function of shear rate curves using the Bingham-plastic flow model, which shows a good agreement with the experimental results. We find that yield stress obtained in shear rate sweep mode was larger than that in the shear strain and shear stress sweep mode because, in shear strain and shear stress mode, the responding strain (or stress) may be unable to follow the stress (or strain) applied and a smaller value of strain (or stress) was observed. The amplitude sweep reveals a transition from viscoelastic-to-viscous behavior at the critical strainγcrt = 0.1%. The storage modulus (G') of the MR fluid showed a stable plateau region over the small strain area γ ≤ γcrt and G'independent of strain amplitude. The frequency sweep demonstrated that storage moduli (G') exhibit elastic response and stable plateau region over the entire frequency range, suggesting the distinguished solid-like behavior of the MR fluid.
Databáze: OpenAIRE
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