Ceramic is the general term for bai of pottery and porcelain. The ceramic materials are mostly oxides, nitrides, borides and carbides. Electronic ceramics can be divided into high-frequency and ultra-high-frequency insulating ceramics, high-frequency high-dielectric ceramics, ferroelectric and antiferroelectric ceramics, piezoelectric ceramics, semiconductor ceramics, optoelectronic ceramics, resistance ceramics, etc. according to their characteristics. According to the application range, it can be divided into fixed ceramics, electric vacuum ceramics, capacitor ceramics and resistance ceramics. According to the microstructure, it can be divided into polycrystalline, single crystal, polycrystalline and glass phase, single crystal and glass phase (no glass phase ceramics belong to solid phase sintering, and some glass phase ceramics belong to wave phase sintering).
Many ceramics have semiconductor properties, so-called semiconductor ceramics. The nature of resistance changes with temperature can be used for nonlinear resistance (NTC). Iron-based metal oxide ceramics have a negative temperature coefficient of resistance, have chemical and thermal stability, and can be used for non-linear resistors to control the temperature in a wide range. In contrast, the element called positive temperature coefficient thermistor (PTC thermistor) uses semiconductorized BaTiO3 ceramics. This type of ceramic has a rapid increase in resistance at the phase transition temperature. If it is used as a resistance heating element, it can easily and automatically control the temperature around the phase transition temperature.
In addition to single-phase ceramics composed of one compound such as oxide ceramics, nitride ceramics, and carbide ceramics, semiconductor ceramics also include composite ceramics composed of two or more compounds. For example, magnesia-alumina spinel ceramics formed by combining aluminum oxide and magnesium oxide, silicon-oxynitride aluminum ceramics formed by combining silicon nitride and aluminum oxide, and chromium oxide, lanthanum oxide and calcium oxide Lanthanum chromate calcium ceramics, lead lanthanum zirconate titanate (PLZT) ceramics formed by combining zirconia, titanium oxide, lead oxide, and lanthanum oxide, etc.
What is the difference between semiconductor ceramics and general ceramics?
2020 07/13