Magnetorheological characteristics of aqueous suspensions that contain Fe3O4 nanoparticles

• Published in: Colloid and polymer science 2005-08, Vol.283 (11), p.1253-1258
• Main Authors: RWEI, S. P, LEE, H. Y, YOO, S. D, WANG, L. Y, LIN, J. G
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Decay rate; Exact sciences and technology; General and physical chemistry; Magnetic fields; Nanocomposites; Nanomaterials; Nanoparticles; Nanostructure; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Shear rate; Stress concentration; Viscosity
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-005-1314-5

This investigation examines the magnetorheological (MR) characteristics of Fe^sub 3^O^sub 4^ aqueous suspensions. Magnetite particles (Fe^sub 3^O^sub 4^) were synthesized using a colloidal process and their sizes were determined to be normally distributed with an average of 10 nm by TEM. Experimental results reveal that the MR effect increases with the magnetic field and suspension concentration. The yield stress increases by up to two orders of magnitude when the sample is subjected to a magnetic field of 146 Oe/mm. In comparison with other published results, concerning a concentration of approximately 10-15% v/v, this study demonstrates that the same increase can be obtained with a concentration of nano-scale particles as low as 0.04% by volume. The viscosity was increased by an order of magnitude while the shear rate remained low; however, the increase decayed rapidly as the shear rate was raised. Finally, the MR effect caused by DC outperformed that caused by AC at the same current.[PUBLICATION ABSTRACT]