Properties and functions of piezo ceramic materials

Mechanical properties

Piezoceramic materials are materials with good rigidity and high hardness among engineering materials, and their hardness is mostly above 1500HV. Ceramics have high compressive strength, but low tensile strength, poor plasticity and toughness.

thermal properties

Ceramic materials generally have a high melting point (mostly above 2000°C), and have excellent chemical stability at high temperatures; the thermal conductivity of ceramics is lower than that of metal materials, and ceramics are also good heat insulating materials. At the same time, the coefficient of linear expansion of ceramics is lower than that of metals, and ceramics have good dimensional stability when the temperature changes.

electrical characteristics

Most piezoceramics plate have good electrical insulation, so they are widely used to make insulating devices of various voltages (1kV~110kV). Ferroelectric ceramics (barium titanate BaTiO3) have a high dielectric constant and can be used to make capacitors. Under the action of an external electric field, ferroelectric ceramics can also change shape and convert electrical energy into mechanical energy (with the characteristics of piezoelectric materials). It can be used as amplifier, record player, ultrasonic instrument, sonar, medical spectrometer, etc. A small number of ceramics also have the characteristics of semiconductors and can be used as rectifiers.

chemical properties

piezo ceramic materials are not easily oxidized at high temperatures, and have good corrosion resistance to acids, alkalis, and salts.

optical properties

Piezo ceramic materials also have excellent optical properties and can be used as solid-state laser materials, optical fiber materials, optical storage, etc. Transparent ceramics can be used for high-pressure sodium lamps, etc. Magnetic ceramics (ferrite such as: MgFe2O4, CuFe2O4, Fe3O4) have broad prospects in the application of audio tapes, records, transformer cores, and large computer memory components.

Function:

Functional piezo ceramics transducer usually have special physical properties and involve many fields. The characteristics and applications of commonly used functional piezo ceramics are shown in the table.