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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 – PowerPoint PPT presentation

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Title: Magnetorheological Fluids


1
Magnetorheological Fluids
http//genchem.chem.wisc.edu/demonstrations/solid_
state/pages/ferrofluids.htm
  • Paul Longwell
  • Hollidaysburg Area High School
  • 2007

2
  • 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.

3
  • Magnetorheological Fluids
  • the ferromagnetic particles are forced into an
    aligned arrangement when the fluid is placed in a
    magnetic field

4
  • 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.

5
  • 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.

6
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.

7
  • 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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8
  • 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.

9
  • 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.

10
  • 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.

11
  • Making Nanowire Particles for the Fluid
  • The cobalt nanowires are now rinsed and stored
    under a vacuum in vials.

12
  • 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.

13
  • Analyzing Magnetorheological Fluids
  • The chips are loaded into a Scanning Electron
    Microscope (SEM) for analysis.

14
  • Analyzing Magnetorheological Fluids

Nanowires arranged in the absence of a magnetic
field
Nanowires aligned in a field of approximately 1
Tesla.
15
  • 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.
16
  • Applications of MR Fluids

17
  • Applications of MR Fluids

18
  • Applications of MR Fluids

19
  • Applications of MR Fluids

20
  • Thank You
  • Dr. Richard Bell
  • The Pennsylvania State University, Altoona
    College
  • Chemistry Department
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