On the theory of rheological properties of bimodal magnetic fluids

This work deals with the theoretical study of rheological properties of a suspension of micron-sized magnetizable particles in a nanodisperse ferrofluid. In recent years, these systems have been synthesized by several teams in order to enhance technological properties of traditional magnetic fluids. We suppose that the micron-sized particles, under the action of an applied magnetic field, form linear chain-like aggregates. Analysis shows that the presence of the ferrofluid can significantly increase the magnetoviscous effect in the suspension of the particles. Unlike the traditional models of magnetorheological suspensions (MRSs) with chains, we have studied the effect of mutual magnetization of particles in chains. Estimates show that this effect significantly increases macroscopical viscous stress in the suspensions and that is why it must be taken into account for theoretical descriptions and interpretation of experiments on the rheological properties of magnetic suspensions.