High temperature ceramic chemical name is called alumina ceramics

High temperature ceramic chemical name is called alumina ceramics, it was based on the alumina as main raw materials.

What is the difference between it and common ceramic?

From the manufacturing process, the method of making high temperature ceramic and ceramic are similar, need through raw material processing, molding, drying, high temperature sintering process.The difference is that the high temperature ceramic some special requirements on raw materials, namely must use specially made of pure aluminum oxide.Traditional silicate ceramic is the use of clay, feldspar and quartz as raw materials, the proportion of the three of them has much to do with the sintering temperature and refractory.Was later found in the ceramic material has three main material: one is the low melting point of alkali metal oxide for the oxidation of sodium, potassium oxide is a kind of form of silicate base composition of the silica is a kind of high melting point of oxide, alumina.Design more and more products produced after the birth of alumina, alumina ceramic, alumina ceramic block, and the shape of the various types of alumina ceramic products. 

When one of the alumina content gradually increased, ceramic ability under high temperature.Containing 70% alumina ceramics, for example, the highest temperature is 1400 ℃, 90, a 95% alumina 1500 a 1550 ℃, 99% of alumina is up to 1700 a, 1800 ℃, and contain more than 99.5% of the alumina can reach more than 1900 ℃.Made of pure aluminum oxide to ceramic material, of course, also will arouse people's interest.

In 1924, a man called roof in Germany pure alumina powder, specimens made from ceramic molding method, at about 2000 ℃ temperature fire, had got a piece of white jade and hard special ceramics, such as alumina ceramic block, now it is the world's first piece of pure alumina ceramics.But until 1933, Germany's Siemens company to "sintered corundum" name. 

Best talent is high temperature resistant, high temperature ceramic in the air can be under 1980 ℃ high temperature resistant, can be called "general heat".To do this, use it made of furnace tube, crucible, gas turbine, blade, etc., can be used in the high temperature of 1600 ℃, without deformation.A lot of molten metal to its helpless, many chemicals can't infringe it, use it to make experiment of high temperature of container is appropriate.Alumina ceramics are of such a high resistance to high temperature, is itself a high melting point, up to 2051 ℃.Under this temperature, it is very stable, won't have any change on the crystal structure, which means it is only a state of crystallization, the alpha alumina, also called corundum.

High temperature ceramic and exceptionally hard, almost with corundum hardness.Alumina ceramic chip and the production of alumina ceramic block, to break the general ceramic heat resistant and shock.At the same time, in addition to diamond and boron carbide and silicon carbide, and in recent years, the rise of a few material such as cubic boron nitride, its hardness is second to none.Its mechanical strength is generally 3-6 times of the ceramic, made with the cutting tool, is really "cut steel such as mud".It is especially suitable for high speed cutting, do not need to change the knife and knife, than cemented carbide cutting tools in general can improve working efficiency, one to several times.