Non-linear magnetorheological behaviour of an inverse ferrofluid

The non-linear magnetorheological behaviour is studied of a model system consisting of monodisperse silica particles suspended in a ferrofluid. The stress/strain curve as well as the flow curve was measured as a function of volume fraction silica particles and field strength, using a home-made magnetorheometer. Both curves were found to scale linearly with the volume fraction and quadratically with the magnetic moment of the silica particles. Affine deformation cannot lead to the observed yield stresses. Instead, a bead–rod model is described that gives results closer to what is observed experimentally. A master curve for the viscosity was obtained by plotting the dimensionless viscosity versus the Mason number, Mn. The free single chain model of Martin and Anderson does not give a good description of the measured curves. This may be due to the simplifications with respect to the microstructure of and processes in the suspension.

[1]  Wu,et al.  Field-Induced Structures in Ferrofluid Emulsions. , 1995, Physical review letters.

[2]  H. Lekkerkerker,et al.  Sedimentation of bidisperse, uncharged colloidal sphere suspensions : influence of viscosity and irregular surfaces , 1996 .

[3]  R. E. Rosensweig,et al.  Magnetorheological fluid composites , 1996 .

[4]  A. Philipse,et al.  Preparation and magnetisation of a silica-magnetite inverse ferrofluid , 1999 .

[5]  A. Skjeltorp.  One- and two-dimensional crystallization of magnetic holes , 1983 .

[6]  J. W. Jansen,et al.  Preparation and characterization of spherical monodisperse silica dispersions in nonaqueous solvents , 1981 .

[7]  M. Shliomis,et al.  Magnetic properties of ferrocolloids , 1990 .

[8]  Daniel J. Klingenberg,et al.  A microstructural investigation of the nonlinear response of electrorheological suspensions , 1995 .

[9]  John P. McTague,et al.  Magnetoviscosity of Magnetic Colloids , 1969 .

[10]  Liu,et al.  Simulation of the formation of nonequilibrium structures in magnetorheological fluids subject to an external magnetic field. , 1996, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[11]  Robert A. Anderson,et al.  Chain model of electrorheology , 1996 .

[12]  S. Odenbach,et al.  Shear dependence of field-induced contributions to the viscosity of magnetic fluids at low shear rates , 1998 .

[13]  W. Stöber,et al.  Controlled growth of monodisperse silica spheres in the micron size range , 1968 .

[14]  Microstructural studies of electro-rheological fluids under shear , 1995 .

[15]  J. W. Jansen,et al.  Light scattering of colloidal dispersions in non-polar solvents at finite concentrations. Silic spheres as model particles for hard-sphere interactions , 1983 .

[16]  R. Rosensweig,et al.  Magnetorheology of ferrofluid composites , 1995 .

[17]  H. Lekkerkerker,et al.  Phase Separation in Bimodal Dispersions of Sterically Stabilized Silica Particles , 1993 .