Micro-phenomenon and viscosity features of magnetorheological fluids at external field

Magnetorheological finishing (MRF) is a technique in which a magnetic-field stiffened ribbon of MR fluid is used to polish a workpiece. MR fluids are essentially suspensions of magnetizable particles immersed in a nonmagnetic fluid. These complex fluids show a unique ability to undergo rapid, nearly completely reversible, significant changes in their mechanical and optical properties upon application of an external magnetic field. The aim of this work is essentially to investigate the effect of microstructure and viscosity behavior of magnetorheological suspensions under the external electro-magnetic field. A viscometer equipped with a circular shape electro-magnetic coil around the testing tube is used. The viscosity of the MR fluids is experimentally studied with the change of the magnetic density. The microstructure and behavior of bending chains in MR fluids are observed by applying an electro-magnetic field.