Piezoelectric Materials & Applications

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

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)

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.

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.

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)

Impact of Piezoelectric Materials

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

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.

• 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.

Advantages & Disadvantages

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.