Piezoelectric ceramics, a functional ceramic material capable of converting mechanical energy and electrical energy to each other, belongs to inorganic non-metallic materials. Piezoelectric ceramics use their materials under the action of mechanical stress, cause the internal positive and negative charge center relative displacement and polarization, resulting in the material at both ends of the surface sign the opposite of the binding charges that the piezoelectric effect is produced, with sensitive characteristics, piezoelectric ceramics are mainly used in the manufacture of ultrasonic transducer, underwater acoustic transducer, electro-acoustic transducer, ceramic filter, Ceramic transformers, Ceramic discriminator, high-voltage generators, infrared detectors, acoustic surface wave devices, electro-optical devices, ignition ignition devices and piezoelectric gyroscope, in addition to the High-tech field, it is more in the daily life for people to serve, for people to create a better life and efforts.
The commonly used piezoelectric ceramics have barium titanate system, two elements of lead zirconate titanate and the addition of a third ABO3 in two-element system (a for the second valence metal ions, b means four valence metal ions or several ions are the sum of positive four valence) compounds, such as: PB (MN1/3NB2/3) O3 and Pb (co1/3nb2/ 3) ternary system composed of O3 etc. If a fourth or more compound is added to the ternary system, it can be composed of four-element or multiple-series piezoelectric ceramics. In addition, there is a kind of niobium-acid salt series of piezoelectric ceramics, such as potassium sodium niobate (Na0.5 · K0.5 · NbO3) and strontium barium niobate (bax· Sr1-x· NB2O5) and so on, they do not contain toxic lead, in favor of environmental protection.
Piezoelectric ceramics have sensitive characteristics, can be extremely weak mechanical vibration into electrical signals, can be used in sonar systems, meteorological detection, telemetry environmental protection, home appliances and so on. Piezoelectric ceramic sensitive to external forces so that it can even detect more than 10 of meters of flying insects flapping wings on the air disturbance, using it to make a piezoelectric seismograph, can accurately measure the intensity of earthquakes, indicating the location and distance of the earthquake. This is a big outstanding of piezoelectric ceramics.
The deformation of piezoelectric ceramics produced by electric field is very small, no more than one out of 10,000 of their own size, do not underestimate this small change, based on the principle of the precise control mechanism-piezoelectric actuator, for precision instruments and machinery control, microelectronics technology, bioengineering and other fields are a great gospel.
Resonator, filter and other frequency control devices, is the key device to determine the performance of communication equipment, piezoelectric ceramics in this area has obvious advantages. It has good frequency stability, high precision and wide application frequency range, and small size, no moisture, long life, especially in the multi-channel communication equipment can improve anti-jamming, so that the past electromagnetic equipment can not be compared to face the fate of the alternative.