The classification of piezoelectric materials used

The first kind is inorganic piezoelectric materials, piezoelectric crystal and piezoelectric ceramic piezo crystals, generally means piezoelectric offnormal crystal, Piezoelectric ceramics is normally piezoelectric polycrystal.

Refers to the use of piezoelectric ceramic raw materials necessary ingredient in the mixed, molding, high temperature sintering, the powders with solid instead of sintering process and subtle grain without rules set into negative. Piezoelectric ceramics is, in fact, is also called piezoelectric ceramic ferroelectric. In this ceramic grain between ferroelectric dependence, ferroelectric scope from spontaneous polarization direction of 180 dependence and reverse parallel polarization direction perpendicular spontaneous composition, the scope of 90 dependence on artificial polarization (n) strengthen dc field conditions, spontaneous polarization direction of electric field in full arrangement in the electric field and keep remaining after removal, therefore has the macroscopical intensity of polarization of piezoelectric properties. Such as: barium titanate BT, zirconium lead titanate PZT and modified zirconium lead titanate, lead metaniobate, lithium niobate lead PBLN, modification of barium titanate lead PT, etc. The successful development of this kind of material, promote the sound transducer, piezoelectric sensors of various piezoelectric devices and improves the performance.

Generally refers to a piezoelectric crystal, refers to the bridgman-stockbarger piezoelectric crystal lattice space according to the long-term growth of crystal and orderly. The crystal structure, so it is not symmetrical center of piezoelectric properties. Such as crystal (quartz crystal), gallium, ge acid lithium, ge acid titanium and iron transistor lithium niobate, litao3 etc.

In comparison, the piezoelectric ceramic piezo sex is strong, dielectric constant high, can be made into any shape, but the mechanical quality factor and low power loss and poor stability and suitable for power transducer and broadband filters, but for high frequency, the application of high stability application is not ideal. Quartz crystal piezoelectric piezoelectric weak, dielectric constant is very low, by cutting type restriction exists, but limited size, high stability, high mechanical quality factor for much of the frequency control standard vibrator, high selectivity of high-frequency (narrow bandpass filter and high frequency, of high-temperature ultrasonic transducer etc. Recently, because of magnesium lead (Pb niobic Mg1/3Nb2/3) O3 bridgman-stockbarger experiment.it 90%, d33 Kp mohan (10-9 experiment.it 3C/N, p ε 20,000) at home and abroad, the specific properties of this kind of material is started, but because of its low Curie, ShiYongHua from a distance.

The second is the organic piezoelectric materials, polymer, such as partial piezoelectric polytetrafluoro-ethylene (PVDF) (film) and the other as a representative of the piezoelectric (film) and other organic materials. This kind of material and material flexibility, low density, high voltage and low impedance (g), constant advantages for attention, and developing very rapidly, and now, the pressure sensor underwater acoustic ultrasound measurement, etc. Used detonated Deficiency is piezoelectric strain constants (d), as an active launch by great limit. Transducer。

The third type is compound piezoelectric materials, this kind of material is in organic polymer base material embedded flake, stick, rods, or powder piezoelectric materials. The acoustic, acoustic, ultrasonic and medicine etc widely applied. If it is made, not only has high underwater acoustic transducer hydrostatic pressure response rate, and impact resistance, damage and usable with different depth.