Preparation and Rheological Properties of Core-shell Particles Magnetic Fluid

Magnetic fluids were prepared using monodispersed iron/silica (Fe/SiO2) ellipsoidal composite particles which were modified by Tween-20 and dispersed in an oily medium as the magnetic materials.The rheological properties of the magnetic fluids were studied by rheometer.The results showed that when the shear rate was small,viscosity of the magnetic fluids raised with the increase of the magnetic field strength.When the shear rate was large,viscosity became very samll and no longer changed with the increase of the magnetic field strength.When the magnetic field strength was certain,the magnetic fluids showed obvious shear thinning.Under small oscillator shear loads,the viscoelastic behavior of the magnetic fluids was different from that of the normal ones.