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 strainγ_crt = 0.1%. The storage modulus (G^') of the MR fluid showed a stable plateau region over the small strain area γ ≤ γ_crt 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.

在这项工作中，使用具有亲水性碳壳作为添加剂的铁纳米粉，研究了微米级片状羰基铁（CI）水基磁流变（MR）流体的流变响应和沉降稳定性。使用平行板旋转流变仪，在剪切速率，剪切应变和剪切应力扫描模式下，在有磁场和无磁场的情况下测量了含1 wt％铁纳米粉的MR流体的流变行为。磁场强度从0到131 kA / m不等，在存在磁场强度的情况下，微米片状CI和铁纳米粉末颗粒会形成坚固的柱状结构。观察到，使用1wt％的具有亲水性碳壳的铁纳米粉，增强了MR悬浮液的流变响应和沉降稳定性。我们使用宾厄姆塑性流模型拟合了剪切应力与剪切速率曲线的函数，这与实验结果吻合良好。我们发现，在剪切速率扫描模式下获得的屈服应力大于在剪切应变和剪切应力扫描模式下获得的屈服应力，因为在剪切应变和剪切应力模式下，响应应变（或应力）可能无法跟随应力（或应变），观察到较小的应变（或应力）值。振幅扫描揭示了临界应变下从粘弹性到粘滞行为的过渡 在剪切应变和剪切应力模式下，响应应变（或应力）可能无法跟随施加的应力（或应变），并且观察到较小的应变（或应力）值。振幅扫描揭示了临界应变下从粘弹性到粘滞行为的过渡 在剪切应变和剪切应力模式下，响应应变（或应力）可能无法跟随施加的应力（或应变），并且观察到较小的应变（或应力）值。振幅扫描揭示了临界应变下从粘弹性到粘滞行为的过渡γ _CRT  = 0.1％。储能模量（G ^ ^“）MR流体的表现出稳定的平台区域在小应变区域γ  ≤  γ _CRT和ģ ^”应变振幅的独立的。扫频表明，储能模量（G ^'）在整个频率范围内均表现出弹性响应和稳定的平稳区域，这表明MR流体具有独特的固态特性。