Ferrofluids

1
Ferrofluids

• By Eduardo Hernandez

2
Description

• Developed by NASA??
• Composed of magnetite, hematite, or other
  compound containing iron.
• Tiny iron particles covered with liquid coating.
• Surfactant added to water or oil, which gives
  liquid properties.
• Has more than one state of matter (colloidal
  suspensions).
• Lose their magnetic properties at high
  temperatures, known as the curie temperature.

3
How they work

• Prepared by combining appropriate amounts of an
  Fe(II) salt and an Fe(III) salt in basic
  solution.
• Particles of magnetite must remain small to
  remain suspended in liquid medium.
• To keep them small a surfactant is added to the
  liquid medium.
• Surfactant is a long-chain hydrocarbon that is
  attracted to the surface of magnetite particle.
• Surfactant is used as a repellent cushion and
  prevent approach of other magnetite particles.

4
Applications

• Rotating Shaft seals (liquid O-ring)
• Magnetic particles form a barrier which prevents
  debris from entering the interior.
• Performance of loudspeakers
• Provides heat conduction from voice coil to the
  surrounding assembly providing better sound
  quality .
• Biomedical applications
• Researchers attempting to design ferrofluids that
  can carry medications to specific locations in
  the body using magnetic fields.

5
References

• http//en.wikipedia.org/wiki/Ferrofluid
• http//mrsec.wisc.edu/Edetc/background/ferrofluid/
  index.html
• http//engineeringtv.com/blogs/etv/archive/2008/07
  /17/ferrofluids.aspx
• http//commons.wikimedia.org/wiki/Ferrofluids