Classification of alumina ceramics

Alumina ceramics can be divided into high-purity type and ordinary type.

High purity alumina ceramic is a kind of ceramic material with more than 99.9% alumina content. Because its sintering temperature is as high as 1650-1990 ℃, the transmission wavelength is 1-6 μ m. Generally, molten glass is made to replace platinum crucible; It can be used as sodium lamp tube by its light transmittance and alkali metal corrosion resistance; It can be used as integrated circuit substrate and high frequency insulating material in electronic industry.

Ordinary alumina ceramics can be divided into 99 porcelain, 95 porcelain, 90 porcelain and 85 porcelain according to the content of alumina. Sometimes those with 80% or 75% of alumina can also be classified as ordinary alumina ceramics. Among them, 99 alumina ceramic materials are used to make high temperature crucible, refractory furnace tube and special wear-resistant materials, such as ceramic bearings, ceramic seals and water valve pieces; 95 alumina ceramics are mainly used as corrosion-resistant and wear-resistant parts; 85 porcelain can be sealed with molybdenum, niobium, tantalum and other metals, and some can be used as electric vacuum devices.