Introduction of parameters of piezoelectric ceramics

Speaking of ceramics, we all know that ceramics have been around us since ancient times. We display porcelain at home, build tiles for high-rise buildings, including the porcelain bowls we usually eat, and our lives are full of ceramic products. Of course, when Bian Xiao talks about piezoelectric ceramics today, quite a few people will ask, what is piezoelectric ceramics and what is it used for? Ok, today, Bian Xiao will tell you about the parameters of piezoelectric ceramics.

Piezoelectric ceramics is an information functional ceramic material-piezoelectric effect, which can convert mechanical energy and electrical energy into each other. It is also dielectric and elastic. It is widely used in medical imaging, acoustic sensors, acoustic transducers, ultrasonic motors and so on. Piezoelectric ceramics use the relative displacement of internal positive and negative charge centers under the action of mechanical stress to produce bound charges with opposite signs on the two ends of the material, that is, piezoelectric effect, which has sensitive characteristics. Piezoelectric ceramics are mainly used to manufacture ultrasonic transducers, underwater acoustic transducers, electroacoustic transducers, ceramic filters, ceramic transformers, ceramic frequency discriminators, high-voltage generators, infrared detectors, surface acoustic wave devices, electro-optical devices, ignition and detonation devices, piezoelectric gyroscopes, etc. Except for high-tech fields.

Free dielectric constant εT33

The dielectric constant of a dielectric when the strain is zero (or constant), in farad/meter.

Relative dielectric constant εTr3 (relative? Capacitance)

The ratio of dielectric constant εT33 to vacuum dielectric constant ε0, εTr3=εT33/ε0, is a dimensionless physical quantity.

Dielectric loss (dielectric? Loss)

Energy lost in a dielectric under the action of an electric field due to polarization relaxation process and leakage conductance.

Loss tangent tgδ

The current flowing through the ideal dielectric under the action of sinusoidal alternating electric field leads the voltage phase by 90? 0, but due to the energy loss in the piezoelectric ceramic sample, the phase angle ψ of the current lead is less than 90, and the remaining angle δ (δ+ψ = 90) is called the loss angle, which is a dimensionless physical quantity. People usually use the tangent tgδ of the loss angle to represent the size of the dielectric loss, which represents the ratio of the active power (loss power) P to the reactive power Q of the dielectric. Namely:? Electrical quality factor Qe

The value of the electrical quality factor is equal to the reciprocal of the tangent value of the sample loss angle, which is a dimensionless physical quantity expressed by Qe. If the parallel equivalent circuit is used to represent the sample of piezoelectric ceramics in alternating electric field, then? Qe= 1/？ tgδ=ωCR

Well, that's all the parameters of piezoelectric ceramics. Generally speaking, piezoelectric ceramics and other workpieces need professional guidance to complete, and the rest can be explored occasionally. But as the saying goes, it is never too old to learn, and one's life is to make progress in learning. Bian Xiao suggested that friends who want to learn the parameters of piezoelectric ceramics can often study them.

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