piezoelectric composite material

In the 1970s, scientists use piezoelectric ceramic materials(PZT) and non-piezoelectric materials (polymers compound) according to a certain arrangement, thereby forming a combination of piezoelectric materials and non-piezoelectric materials.Piezoelectric composites have their own shortcomings, forming a combination of piezoelectric and non-piezoelectric materials and inhibiting each.it is self-defective piezoelectric composites.

The classification of Piezoelectric tube piezoelectric-sensors is based on their connectivity, where the previous number represents the piezoelectric phase. the latter number indicates connectivity of the non-piezoelectric phase, and a dash connection between the two numbers.For example,piezoelectric composite indicates that the piezoelectric phase has no connectivity in all three directions, and the non-piezoelectric phase is connected in all three directions; 3-1-type piezoelectric composites indicate that the polymer column is connected in three dimensions while the pressure electrical materials have connectivity in one dimension; piezoelectric composites represent piezoelectric tube transducer or rods in accordance with certain .Arranged in a polymer in which the polymer phase has connectivity in all three directions, while the piezoelectric phase only has connectivity in one direction.

Compared with single-phase piezoelectric effect ultrasound piezo element, 3 types piezoelectric composites have higher thickness direction electromechanical.It is coupling coefficient, low acoustic impedance, low transverse electromechanical cohesion coefficient, low dielectric constant, low mechanical quality factor,And better flexibility and controllability. The vibration mode of a type piezoelectric material has two lateral vibrations and thickness vibration.In the application of general medical ultrasonic transducer, the piezoelectric material is only operated in the thickness vibration mode.The piezoelectric phase of the 3 composite material is isolated in the lateral direction by the polymer phase, piezo element vibration sensor can effectively reduce the transverse vibration.The combination of the dynamic modes makes the energy more concentrated in the thickness vibration mode, thus improving the electromechanical coordination of its thickness direction.The coefficient reduces the transverse electromechanical cohesion.

Since the polymer phase introduced the single phase piezoelectric material,The polymer phase material and acoustic impedance are relatively low (typically 25% piezoelectric phase), thereby reducing the overall.The density and acoustic impedance of the piezoelectric material piezos discs results in improved matching properties of the material. Introduction of the polymer phase simultaneously is the dielectric constant of the material, so that the static capacitance of the composite material is smaller, the input impedance increased, and has a good voltage output characteristics. The mechanical quality factor of piezoelectric composite material is only ordinary piezoelectric ceramics.The material is 0.001 times 0.01 day, which is more suitable for making broadband narrow pulse transducers.