Magnetorheological Fluids

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Magnetorheological Fluids
http//genchem.chem.wisc.edu/demonstrations/solid_
state/pages/ferrofluids.htm

• Paul Longwell
• Hollidaysburg Area High School
• 2007

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• Magnetorheological Fluids
• sometimes referred to as ferrofluids
• often made by mixing ferromagnetic particles
  (iron, cobalt, etc) into a carrier fluid such as
  silicone oil or even water.

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• Magnetorheological Fluids
• the ferromagnetic particles are forced into an
  aligned arrangement when the fluid is placed in a
  magnetic field

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• Magnetorheological Fluids
• When the ferromagnetic particles are forced into
  alignment by the field, the shape of the fluid
  can be affected by the field lines.

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• Magnetorheological Fluids
• The alignment of the particles in the fluid will
  also cause the viscosity of the fluid to
  increase, making the fluid seem thicker.

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Making Magnetorheological Fluids

• MR fluids can consist of spherical particles,
  rod-shaped nanowire particles, or a combination
  of both.
• Although spherical particles can be purchased
  commercially, nanowires particles are often
  synthesized in the laboratory. Part of this
  project involved making these nanowire particles.

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• Making Nanowire Particles for the Fluid
• An alumina membrane is used as a template for the
  wires. The alumina disk is just a few hundred
  nanometers thick and is filled with pores that
  vary from 0.02mm to 20mm. By depositing
  ferromagnetic materials into these pores,
  nanowires are formed.

http//www.2spi.com/catalog/spec_prep/filter2.shtm
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http//www.whatman.com/products/?pageID7.57.293
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• Making Nanowire Particles for the Fluid
• Before being placed in the electrodeposition
  cell, the membrane is coated with a layer of
  gallium indium to provide good electrical
  conduction.

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• Making Nanowire Particles for the Fluid
• A second electrode is placed in the opposite end
  of the cell and the depositing solution is poured
  in. In this case, a cobalt electrode and
  solution were chosen.

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• Making Nanowire Particles for the Fluid
• The pores of the alumina disk are now filled with
  cobalt. To extract the cobalt nanowires, the
  alumina membrane is dissolved in sodium
  hydroxide.

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• Making Nanowire Particles for the Fluid
• The cobalt nanowires are now rinsed and stored
  under a vacuum in vials.

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• Analyzing Magnetorheological Fluids
• The cobalt nanowires are suspended in ethanol and
  placed on a silicon chip. For comparison, one
  chip is placed in a magnetic field while the
  other is not.

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• Analyzing Magnetorheological Fluids
• The chips are loaded into a Scanning Electron
  Microscope (SEM) for analysis.

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• Analyzing Magnetorheological Fluids

Nanowires arranged in the absence of a magnetic
field
Nanowires aligned in a field of approximately 1
Tesla.
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• Analyzing Magnetorheological Fluids

A mixture of nanowires and spherical particles
arranged in the absence of a magnetic field
A mixture of nanowires and spherical particles
aligned in a field of approximately 1 Tesla.
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• Applications of MR Fluids

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• Applications of MR Fluids

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• Applications of MR Fluids

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• Applications of MR Fluids

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• Thank You
• Dr. Richard Bell
• The Pennsylvania State University, Altoona
  College
• Chemistry Department