Q: what is Piezoelectric ceramics？

A: Piezoelectric ceramics, a functional ceramic material that can convert mechanical energy and electrical energy, belong to inorganic non-metallic materials. Piezoelectric ceramics use its under the action of mechanical stress, the material causes the internal positive and negative charge centers to shift relative to each other, resulting in polarization, which results in beam spreading with opposite signs on both ends of the material.

The charge is made by the piezoelectric effect and has sensitive characteristics. Commonly used piezoelectric ceramics include barium titanate series, lead zirconate titanate binary system, and the addition of the second system to the binary system.

Three kinds of ABO3 (A means divalent metal ion, B means tetravalent metal ion or the sum of several ions are positive tetravalent) type compounds, such as: Pb(Mn1/3Nb2/3) O3 and Pb(Co1/3Nb2/3)O3 And other ternary system. If a fourth or more compounds are added to the ternary system, a quaternary or multi-element piezoelectric ceramic can be formed. In addition, there is a kind of metaniobate piezoelectric ceramics, such as potassium sodium metaniobate (Na0.5·K0.5NbO3) and barium strontium metaniobate (BaxSr1-xNb205), etc.:

Piezoelectric ceramic positive piezoelectric effect:

When certain dielectrics are deformed by external forces in a certain direction, polarization will occur inside them, and at the same time, positive and negative charges will appear on its two opposite surfaces. When the external force is removed, it will return to an uncharged state. This phenomenon is called the positive piezoelectric effect. Piezoelectric ceramic reverse piezoelectric effect:

When the direction of the force changes, the polarity of the charge also changes. On the contrary, when an electric field is applied to the polarization direction of the dielectric, these dielectrics will also deform. After the electric field is removed, the deformation of the dielectric disappears. This phenomenon is called the inverse piezoelectric effect, or electrostriction.

Multilayer piezo actuators:

The piezoelectric ceramic pieces are co-fired together, the mechanical structure is connected in series, and the circuit structure is connected in parallel to obtain a piezoelectric actuators with large displacement output.