Application: welding device for mask machine.
High-voltage polarization measurement principle and method for piezoelectric ceramics：
1. Polarization principle:
Piezoelectric ceramics must be piezoelectric before they have piezoelectric properties. The so-called polarization is to apply a strong DC electric field to the piezoelectric ceramic, so that the electric domains in the ceramic are aligned in the direction of the electric field, also known as artificial polarization treatment, or single domain treatment.
2. Polarization mechanism:
The polarization mechanism of piezoelectric ceramics depends on its internal structure. Piezoelectric ceramics are made of irregular "mosaics" of small grains. Each small grain can be regarded as a small single crystal in which atoms (ions) are arranged in a regular (periodical) manner. The lattice is composed of a repeating unit-the unit cell. The crystal grains and the crystal lattice directions of the crystal grains are not necessarily the same. From the whole, they are still chaotic and irregular. In order to keep the piezoelectric ceramic in the lowest state of energy (electrostatic energy and elastic energy), there will be several small regions in the grain, and the spontaneous polarization of the unit cell in each region has the same direction, but the spontaneous polarization between adjacent regions The direction is different. The regions with the same direction of spontaneous polarization become electric domains, and the whole ceramic includes many electric domains.
3. Artificial polarization:
Apply a sufficiently high DC electric field to the piezoelectric ceramic, and maintain a certain temperature and time to force the direction of the electric domain, or to force its spontaneous polarization to be oriented. Before polarization, there are many electric domains with different spontaneous polarization directions in each crystal grain. The polarization intensity in the ceramic is zero. During the polarization treatment, the crystal grains can form a single domain, and the spontaneous polarization is arranged in the reverse direction of the external field as much as possible. After the polarization treatment, the external electric field is zero. Due to the internal restoring force (such as the release of internal stress generated by polarization), the spontaneous polarization of each grain can only be oriented to the original external electric field to a certain extent. The polarization intensity is no longer zero. This polarization intensity is called the residual polarization intensity.
4. Polarization type:
Oil bath polarization (thermal polarization), corona polarization and vacuum polarization.