What are advanced ceramic materials?

Advanced ceramics are also called fine ceramics, high-tech ceramics and so on. Advanced ceramics are different from traditional ceramics. Advanced ceramics are made of synthetic high-purity ultrafine powder, with selected ingredients, after molding and sintering under very strict technological conditions. Most of them are polycrystalline sintered bodies, but also single crystal films, fibers, amorphous ceramics and other forms.

The disadvantages of traditional ceramics are high strength, but brittleness, poor reliability and difficulty in processing and welding. Advanced ceramics have the characteristics of high strength, wear resistance, light weight, high temperature resistance and corrosion resistance, and have many special properties such as sound, electricity, light, heat and magnetism. Therefore, advanced ceramics are widely used, from integrated circuit substrates, capacitors, transformers, sensors to magnetohydrodynamic generator electrodes; From artificial teeth to bioreactors, it is widely used in various fields of modern science and technology, and its application scope is unmatched by any material, so it is also called "universal material".

Advanced ceramics used as structural materials are mostly silicon nitride, silicon carbide, zirconia and alumina ceramics developed at home and abroad.

Silicon nitride ceramics have excellent properties such as high temperature resistance, good thermal shock resistance, small high-temperature creep, very wear resistance, corrosion resistance and small specific gravity, and are the most promising high-temperature materials for heat engines.

Silicon carbide ceramic material is a superhard material, which not only has excellent properties at room temperature, but also has the best mechanical properties at high temperature. The high temperature strength from room temperature to 1000℃ remains almost unchanged. This material is the most stable non-oxide ceramic material, with excellent oxidation resistance, acid and alkali corrosion resistance and wide application.

Alumina ceramics generally refer to alumina ceramics with a content of more than 70%, and some of them are also called corundum. It is not only a traditional refractory and engineering ceramic, but also a widely used electronic ceramic and bioceramic.

Alumina ceramics are very easy to sinter and reach theoretical density. The sintered product is translucent and has very high transmittance for visible light and infrared light. But also rich in raw materials, low in price and very mature in preparation process. After being transparent, ceramics can have many uses in optics. Semi-transparent alumina ceramics have good light transmittance, high temperature resistance, chemical corrosion resistance, thermal shock resistance and high insulation, which provides lamp materials for manufacturing the third generation high-pressure sodium lamp. It can also be used as a window material for fighter planes and missile heads to transmit infrared light. Once alumina transparent ceramics are successfully developed, various transparent ceramics such as magnesium oxide and yttrium oxide can be developed through similar processes.