Rheological properties and dispersion stability of magnetorheological (MR) suspensions
Rheological properties and dispersion stability of magnetorheological (MR) suspensions
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DOI：
10.1007/s003970000150
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发表时间：
2001-05-01
期刊：
影响因子：
2.3
通讯作者：
Park, OO
中科院分区：
文献类型：
--
作者：
Chin, BD;Park, JH;Park, OO
本文对磁流变液的流变响应和分散稳定性进行了实验研究。制备了磁铁矿和羰基铁颗粒的悬浮液作为模型MR流体。在外磁场（H-0）和稳定剪切流下，屈服应力取决于H-0（3/2）。屈服应力仅在低浓度下与颗粒体积分数呈线性关系，在高浓度下增加较快。研究了磁流变液在小应变振荡剪切流中的流变行为与应变幅值、频率和外加磁场的关系。为了提高磁流变液的稳定性，在羰基铁悬浮液中添加了铁磁性Co-γ-Fe 2 O3和CrO 2颗粒作为稳定剂和增稠剂。这样的针状颗粒似乎在相对大的羰基铁颗粒之间的空间排斥中起作用，导致改善的稳定性，以防止致密铁颗粒的快速沉降。此外，含有添加剂的MR悬浮液表现出更大的屈服应力，特别是在较高的磁场强度。
In the present article, the theological responses and dispersion stability of magnetorheological (MR) fluids were investigated experimentally. Suspensions of magnetite and carbonyl iron particles were prepared as model MR fluids. Under an external magnetic field (H-0) and a steady shear flow the yield stress depends upon H-0(3/2). The Yield stress depended on the volume fraction of the particle (phi) linearly only at low concentration and increased faster at high fraction. Rheological behavior of MR fluids subjected to a small-strain oscillatory shear flow was investigated as a function of the strain amplitude, frequency, and the external magnetic field. In order to improve the stability of MR fluid, ferromagnetic Co-gamma -Fe2O3 and CrO2 particles were added as the stabilizing and thickening agent in the carbonyl iron suspension. Such needle-like particles seem to play a role in the steric repulsion between the relatively large carbonyl iron particles, resulting in improved stability against rapid sedimentation of dense iron particles. Furthermore, the additive-containing MR suspensions exhibited larger yield stress, especially at higher magnetic field strength.