Rheological response of magnetorheological suspensions sediments and its implications for redispersibility

This work reports an investigation into the redispersibility of magnetorheological suspensions (MR suspensions) by testing the rheological properties of suspension sediment. By using a new freeze-sampling method, slices of sediment were taken from the bottom of the container with little changes on shear history which makes it possible to employ rheological measurement. Size distribution of particles contained in sediment was studied by a laser scattering method. Oscillatory and steady shear was employed to studying the rheological viscoelastic and flow behavior. Also, thixotropy and recovery behavior was also studied. The results obtained proved that redispersibility is a multifactor-dependent property which can be reflected from rheological responses of MR suspensions' sediment. Hydrodynamic force and particle interaction which have significant influence on those properties were analyzed in this study. In addition, indexes correspond to different rheological properties were put forward to make a comparison quantitatively between traditional MR suspensions.