Magnetorheology of ferrofluid composites

• Published in: Journal of magnetism and magnetic materials Vol. 149; no. 1; pp. 53 - 56
• Main Authors: Popplewell, J., Rosensweig, R.E., Siller, J.K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 1995; Elsevier Science
• Subjects: Composite materials; Composition effects; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic field effects; Magnetic fluids; Magnetic properties and materials; Mechanical variables measurement; Particle size analysis; Phase transitions; Physics; Rheology; Small particles and nanoscale materials; Solidification; Studies of specific magnetic materials; Yield stress; Composite materials; Rheology; Mechanical properties; Stress-strain relation; Ultrafine particle; Experimental study; Applied load; Magnetic fluids
• ISSN: 0304-8853
• DOI: 10.1016/0304-8853(95)00336-3

Composites consisting of nonmagnetic particles with sizes in the micron range suspended in a ferrofluid constitute an inverse magnetorheological fluid. Structuring occurs in an applied magnetic field and can result in the solidification of the composite. Above a critical level of applied stress the material further transforms to a liquid state. Data confirming the existence of a solidified state are presented based on constant shear rheological measurements. Measurements of the yield stress compare favorably with predictions of theory based on the analysis of unsymmetric stresses in the unyielded, anisotropic medium.