Preparation and Characterization of Iron-Based Magnetorheological Fluids Stabilized by Addition of Organoclay Particles

Abstract

Suspensions of micrometer-sized iron particles (10 vol %) dispersed in kerosene and stabilized by addition of organoclay particles were prepared. The magnetization curves of these suspensions were measured, and their sedimentation and redispersion behaviors were analyzed as a function of clay concentration by means of optical and rheological methods. Furthermore, their magnetorheological properties were investigated using a controlled rate magnetorheometer and the effect of clay concentration on these properties was also analyzed. These experiments showed that the addition of clay slows down iron particle settling and eases the redispersion of the iron-based suspensions without masking their magnetorheological properties. Two mechanisms were found to be involved in this behavior: (i) the formation of a clay gel network and (ii) the presence of heterogeneous iron-clay adhesion.

Effect of drop-like aggregates on the viscous stress in magnetic suspensions

“…Note that the stress σ does not depend on the parameter δ of the drop surface tension. This follows both from the general dimensional analysis, as well as from the solution of the system (17,18). As observed in Figure 3 there is a quite good correspondence between theory and experiments.…”

An improved properties of bidispersed magneto-rheological fluids

“…[8][9][10][11] Some problems, such as particle aggregation and settling rate, affect the performance of MR uid and restrict its use in applications. [12][13][14] To rectify these issues, different procedures have been adopted like addition of thixotropic agents or surfactants and use of viscoplastic media, but sometimes these processes hinder the MR effects. Recently, it was reported that the use of ferrouid (FF) is an effective way to reduce the settling rate of micron-sized particles in MR uid.…”

Preparation and characterization of carbonyl iron/strontium hexaferrite magnetorheological fluids

“…Nevertheless, because of the large density mismatch between the magnetic particles (in the range of 4.0-8.0 g/cm 3 ) and the carrier fluids (about 1.0 g/cm 3 ), MRFs are susceptible to serious sedimentation, directly restricting their applications and producibility. As a result, a wide variety of methods have been adopted to improve the stability of MRF: (i) addition of surfactants or polymers (e.g., oleic acid, poly(methyl methacrylate)) (Choi, Park, Cho, & Choi, 2006;Dang, Ooi, Fales, & Strove, 2000), (ii) addition of thickening agents (e.g., organoclays, carbons fibers) (López-López, Vertelov, Bossis, Kuzhir, & Durán, 2007;López-López, Gómez-Ramírez, Durán, & González-Caballero, 2008), (iii) addition of magnetic nanoparticles (Rosenfeld, Wereley, Radhakrishnan, & Sudarshan, 2002;Viota, Gonzalez-Caballero, Duran, & Delgado, 2007;Wereley et al, 2006), and (iv) use of ionic liquids as carriers (Guerrero-Sanchez, Lara-Ceniceros, Jimenez-Regalado, Rasa, & Schubert, 2007). The first solution has been demonstrated to prevent aggregation by means of steric repulsion in many studies.…”