PIEZOELECTRIC MATERIAL
Lead (Pd), chromium (Zr) and titanium (Ti)
PZT piezoelectric ceramics are generally used in approximately 55% and 45% PbZrO3 PbTiO3 solid solution
Lead zirconate titanate (PZT) the characteristic profile
1954 Jaffe et al found that lead zirconate titanate (Lead Zirconate Titanate, PZT) solid solution (solid-solution) material has excellent piezoelectric properties (piezoelectric properties) since, PZT incurs a wide range of applications in various piezoelectric devices (sensors (sensors), the actuator (actuators) and the voltage generator (voltage generators), etc.).
PZT is essentially a xPbZrO3- (1-x) PbTiO3 (0 <x <100) of the solid solution phase two-component system composed. Its chemical formula can be expressed as Pb (ZrxTi1-x) O3, due to the perovskite structure to which it belongs, so that its electric field is generated after the addition of the ferroelectric properties.
The piezoelectric ceramic powder mainly lead zirconate titanate (PZT) are composed of zirconium oxide was added in the (ZrO2), and lead oxide (PbO) and titanium oxide (TiO2) powder raw material, etc., appropriate to add a small amount of additive after the number of road made through rigorous production processing program. After completion of the ceramic powder, and then compressed using a press to make a variety of shapes, and then at a temperature of about 1350 ℃ sintering, the resulting product after completion of the polarization, that is, the piezoelectric ceramic wafer.
Piezoelectric / piezomagnetic composite system belongs to a new smart materials, such smart composites are made of piezoelectric material and pressure-magnetic materials (magnetic telescopic material) the composition, will produce the piezoelectric and magnetic pressure of the original single-phase magnetic coupling effects that are not material, this coupling effect will enhance the electric and magnetic fields of the original single-phase materials about 10-100 times. So we can use this feature to improve the bandwidth of the piezoelectric material with a small pressure magnetic materials, small signal, the disadvantage of small actuators. It can be widely used in the electric signal into mechanical energy on the signal converter. For example probe aerospace, automotive, electronics, civil engineering, medicine and other projects, sensors, actuators, energy exchange, image processing, ultrasound, sonar and non-destructive testing such as the above.
→ mechanical energy to electrical energy
When an AC voltage is applied, the object will be positive and negative fluctuations in the mechanical direction. Vibration frequency and material properties,
Component size and design. If the ultrasound range, it becomes ultrasonic shock element, can be used as ultrasound
Washer, sonar, ultrasonic welding machine; If the sonic range, can be used as a speaker, tweeter,
Buzzer.
→ electrical energy to mechanical energy
When the external force is applied, the induced voltage will be the object. There are positive and negative changes in the size of the external force, the induced voltage is also negative
Changes in size. Applied to the detection of water, the water pressure wave generated by moving objects, the piezoelectric element is converted into an electrical
Wave, and detected. Also be applied to lighter, gas stove ignition element inside.
Piezoelectric effect (mechanical energy conversion and energy)
Piezoelectric effect (piexoelectrics) is a material with a mechanical power
Exchange phenomenon, this phenomenon was first used in 1880 by Pierre Curie and
Jacques Curie brothers discovered.
Piezoelectric materials have piezoelectric effect is due to the special arrangement of atoms in the crystal lattice between
Such material should stand with electric field coupling effects.
There are two piezoelectric effect, piezoelectric effect (direct piezoelectric effect)
And inverse piezoelectric effect. (Converes piezoelectric effect).
General piezoelectric ceramic material barium titanate (BaTiO3), Thailand acid lead zirconate (PZT),
Quartz crystal class (Crystal), tourmaline, Rhodes salt, tantalate, niobate, etc.
Or filmic zirconia (ZnO).
1 because it has piezoelectric properties of piezoelectric ceramics (Piezoelectricity) can convert electrical energy into mechanical energy and of each other, a very wide field of application.
2 Among them, lead zirconate titanate (PZT) due to their excellent piezoelectric properties, as currently used in surface acoustic wave sensor element and the potential usefulness of the largest and highest piezoelectric ceramic thin film materials.
3 using the coating technology has now been booming, with the sol - gel PZT piezoelectric film production. The actual semiconductor technology in conjunction with the surface-acoustic wave sensing element, and identified biosensing test Results.
Causes the piezoelectric effect
1 charge and mutual causality between strain, making the presence of the electric dipole moment of a crystal can be generated by external force to move the charge charged body, the charged body called on the structure. As long as the object of the crystalline structure can be affected by the presence of an external force to move the electric dipole moment, will produce another electromechanical energy conversion phenomenon, namely the root of the piezoelectric phenomena.
2 has a piezoelectric material which is a prerequisite for the presence of an asymmetric center (non-centrosymmetry) crystal structure, i.e., the center of positive charge and negative charge centers are not located in the same position, so that the negative charge can not exhibit neutralization properties, there will be the presence of electric dipole moment.
Piezoelectric materials
(1) single crystal (signal crystal): such as quartz (quartz), lithium niobate (LiNbO3), lithium tantalate (LiTaO3).
(2) a thin-film (thin film): aluminum nitride (AlN), zinc oxide (ZnO).
(3) ceramic (ceramic): such as barium titanate (BT), lead zirconate titanate (PZT).
(4) polymer (polymer): such as PVDF.
Lead zirconate titanate PZT
Chemical Formula: Pb (Zrx, Ti1-x) O3
Structure: perovskite (Perovskite)
Two-component by xPbZrO3- (1-x) PbTiO3 (0 <x <100) that consists of a solid solution system
