Test Principle of Piezoelectric Ceramic Pyroelectric Coefficient

Test Principle of Piezoelectric Ceramic Pyroelectric Coefficient

The piezoelectric ceramic pyroelectric coefficient tester can measure the dielectric constant, curie temperature, pyroelectric coefficient, longitudinal piezoelectric strain constant d33, electromechanical coupling coefficient and other parameters of piezoelectric ceramics. It is a piezoelectric material testing device .

Piezoelectric ceramics transducer are a class of electronic piezoceramic materials with piezoelectric properties. The main difference from typical piezoelectric quartz crystals that do not contain ferroelectric components is that the crystal phases that constitute its main components are all ferroelectric crystal grains. Since piezoceramics are polycrystalline aggregates with randomly oriented grains, the spontaneous polarization vectors of individual ferroelectric grains are also chaotically oriented. In order for the ceramics to exhibit macroscopic piezoelectric properties, it is necessary to place the piezoelectric ceramics disk under a strong DC electric field for polarization treatment after they are fired and coated with multiple electrodes on the end faces, so that the original disordered orientation of the respective electrodes The optimal orientation of the vectorization vector is along the direction of the electric field. After the polarization treatment, the piezoelectric ceramics will retain a certain macroscopic remanent polarization strength after the electric field is canceled, so that the ceramics have certain piezoelectric properties.

The pyroelectric coefficient of piezoelectric ceramic materials was measured by charge integration method. This method determines the change in remanent polarization with temperature by measuring the pyroelectric charge accumulated on the capacitor. Piezoelectric constant d33 is one of the important characteristic parameters of piezoelectric ceramics. It is the proportional constant of piezoelectric medium converting mechanical energy (or electrical energy) into electrical energy (or mechanical energy), reflecting the relationship between stress or strain and electric field or electric displacement. The relationship directly reflects the coupling relationship between the electromechanical properties of the material and the strength of the piezoelectric effect.