Special ceramics refer to ceramics with special mechanical, physical or chemical properties, which are used in various modern industries and cutting-edge science and technology. The raw materials used in special ceramics and the required production process are very different from ordinary ceramics, and some countries call them "precision ceramics". Recently, Chinese materials experts have agreed that it would be better to call them "advanced ceramics". Special ceramics can be subdivided into structural ceramics, functional ceramics and tool ceramics according to their performance characteristics and uses.

What are the special fields of application for ceramics? The different chemical composition and organizational structure of special ceramics determine their different special properties and functions, such as high strength, high hardness, high toughness, corrosion resistance, electrical conductivity, insulation, magnetism, light transmission, semiconductor, piezoelectric, photoelectric, electro-optic, Sound and light, magneto-optic, etc. Due to their special properties, this kind of ceramics can be used as engineering structural materials and functional materials in the fields of machinery, electronics, chemical industry, smelting, energy, medicine, laser, nuclear reaction, aerospace and other fields.

From the perspective of raw materials, special ceramics have broken through the boundaries of traditional ceramics with clay as the main raw material. Usually oxides, nitrides, silicides, borides and carbides are the main raw materials. Add a specific formula of inorganic materials to the ceramic body, and then sinter at a high temperature of about 1360 degrees to obtain stable and reliable antistatic properties. , biology and one or more functions. And coupling functions, such as piezoelectric, pyroelectric, electro-optic, acousto-optic, magneto-optic, etc. For example, the treated ceramic fruit knife has a higher density than ordinary ceramic products, and has the advantages of environmental protection, non-toxicity, no rust, and no oxidation.

Taking structural ceramics as an example, it can be divided into four series: zirconia, alumina, silicon nitride, and silicon carbide. Zirconia ceramics are mainly used in civilian fields, such as ceramic knives, watches, mobile phone backplanes, etc. In daily life, alumina is mainly used in medical equipment, food and other fields. These fields have very strict requirements on the density, hardness, toughness and other performance indicators of materials, so the materials are generally high-purity alumina. Ordinary alumina is generally used for products with low requirements due to its low purity. In addition, with the continuous development of alumina ceramic technology, its application range is becoming wider and wider, and it has unique advantages in hardness and corrosion resistance, which will be the key development direction of the industry in the future. Silicon nitride is a special ceramic developed and applied earlier in my country. It has the advantages of good thermal shock resistance, high hardness, good wear resistance, and bending resistance. It is mainly used in cutting tools, high-pressure plungers, heating plates and other fields. The main advantage of silicon carbide ceramics is corrosion resistance, which is mainly used in the chemical industry.

At present, the level of domestic special ceramics is limited to some small and precise parts, and some large-scale equipment and instruments still lack the mastery of their forming technology. However, with its wide application in electronics, medicine, food, military chemical industry and other fields. Special ceramics are playing an increasingly important role in China's development, such as ceramic bearings on aircraft, decks of warships, etc. The development of new materials such as China's special ceramics is also quite rapid.