Advanced ceramics are also called fine ceramics, high-tech ceramics, and so on. Advanced ceramics are different from traditional ceramics. Advanced ceramics use artificially synthesized high-purity ultra-fine powders as raw materials. They are formulated according to selected ingredients. They are manufactured by molding, sintering and other processes under very strict process conditions. of. Most of them belong to polycrystalline sintered bodies, and there are various forms such as single crystal thin films, fibers, and amorphous ceramics.
The disadvantages of traditional ceramics are high strength, but great brittleness, poor reliability, and very difficult machining and welding. Advanced ceramics have high strength, wear resistance, light weight, high temperature resistance, corrosion resistance, and have special properties in many aspects such as sound, electricity, light, heat, and magnetism. Therefore, advanced ceramics have a wide range of applications, from integrated circuit substrates, capacitors, transformers, sensors to magneto-fluid generator electrodes; from artificial teeth to bioreactors, they are used in all fields of modern science and technology. The scope of application is any material Can not be compared, so it has the reputation of "universal material".
As the advanced ceramics used as structural materials, most of the domestic and foreign developments are silicon nitride, silicon carbide, zirconia and alumina ceramics.
Silicon nitride ceramics have excellent properties such as high temperature resistance, high thermal shock resistance, low temperature creep, high wear resistance, corrosion resistance, and low specific gravity. They are the most promising high temperature materials for heat engines.
Silicon carbide ceramic material is a kind of super hard material. It not only has excellent performance at normal temperature, but the most important thing is that its high temperature mechanical properties are the best in ceramic materials now. The high temperature strength from room temperature to 1000 ℃ can be maintained substantially unchanged. This material is the most stable of non-oxide ceramic materials, with excellent oxidation resistance, resistance to various acids and alkalis, and a wide range of uses.
Alumina ceramics generally refer to alumina ceramics with a content of more than 70%, and some are also called corundum. It is not only traditional refractory materials, engineering ceramics, but also widely used electronic ceramics, but also bioceramics.
Alumina ceramics are very easy to sinter, it is easy to reach the theoretical density, the sintered products are translucent, and have very high light transmittance for visible light and infrared light. Moreover, the raw materials are abundant and the price is low, and the production process is very mature. After ceramics are transparent, they can be used in many optical applications. Translucent alumina ceramics have good light transmission properties, coupled with resistance to high temperature and chemical corrosion, can withstand thermal shock, and have high insulation properties, providing a tube material for the manufacture of the third generation light source-high pressure sodium lamps . It can also be used for fighters and missile heads that transmit infrared light. Once alumina transparent ceramics are successfully developed, various transparent ceramics such as magnesium oxide and yttrium oxide can also be developed using similar processes.
What is advanced ceramics?
2019 12/16