Transcript Edward L Gamino Piezioelectrics Materials Science September 21

Piezoelectric Materials
MEEN 3344
Edward L. Gamino
September 21, 2009
Types
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Quartz- first commonly used crystal
Lead Zirconate PZT-most common ceramic in use
today
Rochelle salt
Cane sugar
Bone
Piezoelectric Effect
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The piezoelectric effect was discovered in 1880 by brothers
Jacques and Pierre Curie. They discovered that when a
mechanical stress was applied on crystals (such as tourmaline,
topaz, quartz, Rochelle salt and cane sugar) electrical charges
appeared, and the voltage was proportional to the amount of
stress.
An everyday application example is a car's airbag sensor. The
material detects the intensity of the shock (impact) and sends an
electrical signal which triggers the airbag to deploy.
How Piezoelectricity Works
Example : In a relaxed state with no
forces acting on the positive or negative
charges, they are arranged at the vertices
of a hexagon. The positive and negative
configuration of charges will cancel each
other out and the potential Voltage, a
distance along the x axes will be zero.
If a compressive force (mechanical stress or stress) is applied to the
hexagon along the Y axes direction, the configuration is distorted to
bring two of the positive charges closer together at one end and the
negative charges at the other. This forms a dipole where one end of
the structure is positive and the other negative. Voltage at a distance
along the X axes will now be present. This process is also
reversible.
Applications
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Sonar-first practical application
Vibration Dampeners
Phonographs
Transducers
Airbag sensor
Lighters
Printers
Cell Phones
References
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Callister, William D, and David G. Rethwisch. Fundamentals of
Materials Science and Engineering. New York: Wiley, 2008.
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Jaffe, Bernard, William Cook, Hans Jaffe. Piezoelectric Ceramics.
New York: Gould, 1971
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Buchacz, A. ”Piezoelectric layer modeling by equivalent circuit
and graph method.” Journal of Achievements in Materials and
Manufacturing Engineering 20 (2007).
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Homepage. Piezoelectric Materials.
http://www.piezomaterials.com/index.htm
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Homepage. Piezoelectricity.
http://www.tedlind.net/Piezoelectricity.htm