This document discusses piezoelectric materials and their applications. It begins by explaining that piezoelectricity is the ability of certain materials to generate an electric charge in response to applied mechanical stress. It then provides examples of naturally occurring and man-made piezoelectric materials like quartz, barium titanate, and lead zirconate titanate. The document outlines several applications of piezoelectric materials in sensors, actuators, and as high voltage sources. It concludes by stating that piezoelectricity provides a revolutionary source for green energy through power harvesting.
2. Presented To: RETHWAN FAIZ
Group members:
Name ID
1) Talukder, Mohaiminul hassan 14-25711-1
2) Rahman, Md.Moshiour 14-25832-1
3) Kawsar, Fahmidul hoque 14-25840-1
4) Mahmud, Tanvir 14-25762-1
5) Roy, Mrinmoy 14-26366-1
3. Introduction
Piezoelectricity is the ability of some materials to generate an electric charge
in response to applied mechanical Stress.
The piezoelectric effect is reversible.
Direct piezoelectric effect: charge separation due to stress.
converse piezoelectric effect: occurens of stress and strain when electric
field is applied.
Happens in insulating materials, Insulating Ferroelectrica and materials with
a permanent dipol,In crystals(only crystals without symmetry centre)
4. Working Principle
The positive and negative charges are symmetrically distributed in crystals.
Piezoelectric ceramics are not piezoelectric until the random ferroelectric
domains are aligned by a process known as poling.
Poling consists of inducing DC voltage across the material.
When pressure is applied to an object, a negative charge is produced on the
expanded side and a positive charge on the compressed side.
Once the pressure is relieved electrical current flows through the material.
5. The Process is based on fundamental structure of a crystal
lattice. Crystals generally have a charge balance where
negative and positive charges precisely nullify each other
out along the rigid planes of the crystal lattice. When this
charge balance is disrupted by an external force, such as,
applying physical stress to a crystal, the energy is
transferred by electric charge carriers, creating a surface
charge density, which can be collected via electrodes.
6. Some Piezoelectric materials
Naturally occuring:
-Quarz -Cane sugar -Collagen
-Topaz -DNA
-Rochelle salt -Wood
-many many others -Tendon
Man-made crystals:
-Gallium orthophosphate (GaPO4), a quartz analogic crystal
-Langasite (La3Ga5SiO14), a quartz analogic crystal
Man-made ceramics
Barium titanate(BaTiO3)-Barium titanate was the first petzoelectric ceramic
discovered.
-Lead zirconatetitanate (Pb[ZrxTi1−x]O3 0<x<1)—more commonly known as
PZT, lead zirconatetitanate is the most common piezoelectric ceramic in use
Today
-Lithium niobate (LiNbO3)
8. Applications
Sensor
-Microphones, Pick-ups
-Pressure sensor
-Force sensor
-Strain gauge
Actuators
-Loudspeaker
-Piezoelectric motors
-Nanopositioning in AFM or STM
-Acuosto-optic modulators
-Valves
High voltage and power source
-Cigarette lighter
-Energy harvesting
-AC voltage multiplier
Force sensor
AFM or STM
9. Implementation of Piezoelectricty
in practical life
Energy Harvesting: Vibrations from industrial machinery can also be harvested by
piezoelectric materials to charge batteries for backup supplies or to power low-power
microprocessors and wireless radios.
Piezoelectric elements are also used in the detection and generation of sonar waves.
Inkjet printers: On many inkjet printers, piezoelectric crystals are used to drive the
ejection of ink from the inkjet print head towards the paper.
Diesel engines: High-performance common rail diesel engines use piezoelectric fuel
injectors, first developed by Robert Bosch GmbH, instead of the more common solenoid
valve devices.
10. • Piezoelectric motors: Piezoelectric elements apply a directional force to an
axle, causing it to rotate. Due to the extremely small distances involved, the piezo
motor is viewed as a high-precision replacement for the stepper motor.
• A recent application of piezoelectric ultrasound sources is piezoelectric surgery,
also known as piezosurgery. Piezosurgery is a minimally invasive technique that
aims to cut a target tissue with little damage to neighboring tissues. It has the
ability to cut mineralized tissue without cutting neurovascular tissue and other
soft tissue, thereby maintaining a blood-free operating area, better visibility and
greater precision.
• Ultrasonic piezo sensors are used in the detection of acoustic emissions in
acoustic emission testing.
12. Conclusion
• Piezoelectricity is a revolutionary source for “GREEN
ENERGY”
• Flexible piezoelectric materials are attractive for
power harvesting applications because of their ability
to withstand large amounts of strain.
• Convert the ambient vibration energy surrounding
them into electrical energy.
• Electrical energy can then be used to power other
devices or stored for later use.