Alumina ceramics is a ceramic material mainly composed of alumina (Al2O3), which has good conductivity, mechanical strength and high temperature resistance. What are the common types of alumina ceramics? What are the characteristics?
Classification of alumina ceramics
Alumina ceramics are divided into high-purity type and ordinary type.
High-purity alumina ceramics are ceramic materials with an Al2O3 content of more than 99.9%. Because of its sintering temperature as high as 1650-1990°C and a transmission wavelength of 1-6μm, it is generally made of molten glass to replace platinum crucibles; use its light transmission It can be used as a sodium lamp tube because of its high corrosion resistance and alkali metal corrosion resistance; it can be used as an integrated circuit substrate and high-frequency insulating material in the electronics industry. the
Ordinary alumina ceramics are divided into 99 porcelain, 95 porcelain, 90 porcelain, 85 porcelain and other varieties according to the Al2O3 content. Sometimes those with Al2O3 content of 80% or 75% are also classified as ordinary alumina ceramic series. Among them, 99 alumina porcelain materials are used to make high-temperature crucibles, refractory furnace tubes and special wear-resistant materials, such as ceramic bearings, ceramic seals and water valve plates, etc.; 95 alumina porcelain is mainly used for corrosion-resistant and wear-resistant parts; 85 porcelain Because some talc is often mixed in, the electrical properties and mechanical strength are improved, and it can be sealed with metals such as molybdenum, niobium, and tantalum, and some are used as electric vacuum devices.
Characteristics of alumina ceramics
1. High hardness
According to the measurement of Shanghai Institute of Ceramics, Chinese Academy of Sciences, its Rockwell hardness is HRA80-90, the hardness is second only to diamond, far exceeding the wear resistance of wear-resistant steel and stainless steel.
2. Excellent wear resistance
As determined by the Powder Metallurgy Institute of Central South University, its wear resistance is equivalent to 266 times that of manganese steel and 171.5 times that of high-chromium cast iron. According to our customer follow-up survey over the past ten years, under the same working conditions, the service life of the equipment can be extended by at least ten times.
3. Light weight
Its density is 3.5g/cm3, which is only half that of steel, which can greatly reduce the load on equipment.