Laboratoire de Physique de la Matière Condensée, CNRS UMR 6622, Université de Nice, Parc Valrose, 06108 Nice Cedex 2, France.
J Phys Condens Matter. 2010 Aug 18;22(32):324106. doi: 10.1088/0953-8984/22/32/324106. Epub 2010 Jul 15.
Different samples of cobalt powder were synthesized. Particle size and shape were characterized using electron microscopy and light scattering. These measurements showed that the synthesized powders consisted of monodisperse spheres with average diameters ranging between 63 and 760 nm. These powders were used for the preparation of magnetorheological (MR) fluids by dispersing them in silicone oil. The MR properties of these MR fluids were investigated. It was found that particle size did not have much influence on the MR response of MR fluids, for average particle diameters larger than 100 nm. On the other hand, the MR response decreased appreciably when the average particle diameter was diminished below 100 nm; a theory based on the change of the shape of the aggregates with the size of the particles could explain these observations.
不同的钴粉样品被合成。使用电子显微镜和光散射对粒径和形状进行了表征。这些测量表明，合成的粉末由平均直径在 63 到 760nm 之间的单分散球体组成。这些粉末被用于通过在硅油中分散它们来制备磁流变（MR）流体。这些 MR 流体的 MR 性能进行了研究。发现粒径对 MR 流体的 MR 响应影响不大，对于平均粒径大于 100nm 的情况。另一方面，当平均粒径减小到 100nm 以下时，MR 响应明显下降；一个基于颗粒尺寸下的聚集体形状变化的理论可以解释这些观察结果。
