Mechanical properties
Ceramic materials have the best rigidity and the highest hardness in engineering materials, most of which are above 1500hv. The compressive strength of ceramics is high, but the tensile strength is low, and the plasticity and toughness are poor.
Thermal characteristics
Ceramic materials generally have high melting point (mostly above 2000 ℃), and excellent chemical stability at high temperature; the thermal conductivity of ceramics is lower than that of metal materials, and ceramics are also good heat insulation materials. At the same time, the linear expansion coefficient of ceramic is lower than that of metal. When the temperature changes, ceramic has good dimensional stability.
Electrical characteristics
Most of the ceramics have good electrical insulation, so they are widely used to make insulation devices of various voltages (1kV ~ 110kV). Ferroelectric ceramics (BaTiO3) have high dielectric constant and can be used to make capacitors. Under the action of external electric field, ferroelectric ceramics can also change shape and convert electrical energy into mechanical energy (with the characteristics of piezoelectric materials), which can be used as loudspeakers, phonographs, ultrasonic instruments, sonars, medical spectrometers, etc. A few ceramics also have the characteristics of semiconductors and can be used as rectifiers.
chemical properties
Ceramic materials are not easy to oxidize at high temperature, and have good corrosion resistance to acid, alkali and salt.
optical characteristics
Ceramic materials also have unique optical properties, which can be used as solid-state laser materials, optical fiber materials, optical storage, etc., transparent ceramics can be used for high-pressure sodium lamp, etc. Magnetic ceramics (such as MgFe2O4, cufe2o4, Fe3O4) have a wide range of applications in recording tapes, records, transformer cores, large computer memory elements.
