The document provides an overview of piezoelectric materials, which convert mechanical energy into electrical energy and vice versa. It describes the piezoelectric effect, its two manifestations (direct and converse), and the necessary conditions for materials to exhibit piezoelectricity. Additionally, the document discusses classifications, applications, advantages, and disadvantages of piezoelectric materials across various industries.

1. Introduction on PZT Piezo-electric
KAUNAS UNIVERSITY OF
TECHNOLOGY
Department of Mechanical Engineering
Piezo Electric Information
Prepared By :
Yatinkumar Patel
Kaunas 2016

2. Introduction:
Piezoelectric Material:
Piezoelectric materials are one that possesses the property of converting mechanical
energy into electrical energy and vice versa. This material is used for making devices that
convert mechanical forces into electrical signals (direct piezo effect), electrical signals into
mechanical forces (inverse piezo effect), or electrical signals into electrical signals (successive
use of direct and inverse effects).
Piezoelectric Effect:
Piezoelectric effect discovered in 1880 by French physicists Jacque and Pierre Curie in
quartz crystal. If certain crystals were subjected to mechanical strain, they became electrically
polarized and the degree of polarization was proportional to the applied strain.

3. Types of piezoelectric effect:
Piezoelectric behavior can be manifested in two distinct way:
1. Direct piezoelectric effect.
2. Converse piezoelectric effect.
 Direct piezoelectric effect:
The electrical response to mechanical stimulation is called the direct piezoelectric effect. Also, it
refers to a change in electric polarization that is produced in certain materials when they are subjected to
mechanical stresses. This stress-dependent change in polarization manifests as a measurable potential
difference across the material is called as the direct piezoelectric effect.
 Converse piezoelectric effect:
Deformation of these materials that results from the application of an electric field. The
deformation could lead to either tensile or compressive strains and stresses in the material depending
upon the direction of the electric field, the preferred direction of polarization in the material, and how
the material is connected to other adjacent structures refers as the converse piezoelectric effect.

4. Internal Working:
 The effect is explained by the displacement of ions in crystals that have a nonsymmetrical unit cell.
 When the crystal is compressed, the ions in each unit cell are displaced, causing the electric
polarization of the unit cell.
Because of the regularity of crystalline structure, these effects accumulate, causing the
appearance of an electric potential difference between certain faces of the crystal.
When an external electric field is applied to the crystal, the ions in each unit cell are displaced
by electrostatic forces, resulting in the mechanical deformation of the whole crystal.

5. Classification of Piezoelectric material:
To exhibit piezoelectricity two main necessary condition are:
1.Crystal should have Ionic or partially Ionic bonds.
2.Its structure should have no centre of symmetry.
Piezoelectric materials are usually divided in-to two groups:
1.Hard Piezoelectric Materials.
2.Soft Piezoelectric Material.
But briefly it is divided in many sub divisions according to their Nature as shown in table:
1.Berlinite (AIPO4)
2.Cane sugar
3.Quartz.
4.Rochelle salt.
5.topaz.
6.Tourmaline group material.
7.Dry bone (apatite crystals).
8.Lead titanate (PbTiO3).
1.Tendon.`
2.silk.
3.wood Due to
Piezoelectric texture.
4.Enamle.
5.dentine.
1.Gallium
orthophosphate
(GaPO4).
2.Langasite
(La3Ga5SiO14).
1.Barium titanate (BaTiO3).
2.Lead titanate (PbTiO3).
3.Lead zirconate titanate
4.Zinc oxide (ZnO).
5.Lithium niobate (LiNbO3).
6.Lithium tantalite (LiTaO3).
7.Sodium tungstate
Naturally crystals. Other natural material. Man-made Crystals. Man-made Ceramics.

6. Lead-free piezoceramics
1.Sodium potassium niobate
((K,Na)NbO3).
2.Bismuth ferrite (BiFeO3).
3.Sodium niobate (NaNbO3).
4.Bismuth titanate
(Bi4Ti3+O12).
5.Sodium bismuth titanate
NaBi(TiO3)2.
Polymers
1.Polyvinylidene fluoride (PVDF).
Characteristics Soft ceramics Hard Ceramics
Piezoelectric Constants larger smaller
Permittivity higher lower
Dielectric Constants larger smaller
Dielectric Losses higher lower
Electromechanical Coupling Factors larger smaller
Electrical Resistance very high lower
Mechanical Quality Factors low high
Coercive Field low higher
Linearity poor better
Polarization / Depolarization easier more difficult
 Compression between soft and hard ceramics:

7. Application of piezoelectric material:
Piezoelectric material can be used by the application of both “Direct” as well as “Converse” piezoelectric effect:
Mechanical to Electrical conversion Electrical to mechanical conversion
1.Photograph cartridges 1.Valves.
2.Microphones. 2.Micropumps.
3.Vibration sensors. 3.Earphones and speakers.
4.Accelerometers. 4.Ultrasonic cleaner.
5.Photoflach actuator. 5.Emulsifiers.
6.Gas igniters. 6.Sonic transducers.
7.Fuses.
Sr. no Industry Application
1 Automotive Air bag sensor, air flow sensor, audible alarms, fuel atomizer, keyless door entry,
seat belt buzzers, knock sensors.
2 Computer Disc drives, inkjet printers.
3 Consumer Cigarette lighters, depth finders, fish finders, humidifiers, jewellery cleaners,
musical instruments, speakers, telephones.
4 Medical Disposable patient monitors, fetal heart monitors, ultrasonic imaging.
5 military Depth sounders, guidance systems, hydrophones, sonar.

8. Advantage and Dis-advantage of piezoelectric material:
Advantage 1.Unaffected by external electromagnetic fields.
2.Harvesting energy from human.
3.Pollution free.
4.Easy replacement of equipment
5.It can use for high range of sensors and actuators.
Dis-advantage 1.Crystal is prone to crack if overstressed.
2.May get affected by long use at high temperatures.
3.material should be packed properly and connections sealed and made water
proof and rigid.
4.Cost is too expensive.

9. References:
1. www.elpapiezo.ru/eng/piezoceramic_e.shtml
2. https://www.comsol.co.in/multiphysics/piezoelectric-effect
3. http://www.slideshare.net/piezoelectric-transd
4. https://www.americanpiezo.com/piezo-theory/ceramics.html
5. http://classroom.materials.ac.uk/casePiez.php