Alumina ceramics are divided into high-purity type and ordinary type. High-purity alumina ceramics are ceramic materials with an Al2O3 content of 99.9% or more. Due to their sintering temperature as high as 1650-1990℃ and transmission wavelength of 1～6μm, they are generally made of molten glass to replace platinum crucibles; use their light transmission It can be used as sodium lamp tube in alkali and metal corrosion resistance; it can be used as integrated circuit substrate and high frequency insulating material in the electronics industry.
Ordinary alumina ceramics are divided into 99 porcelain, 95 porcelain, 90 porcelain, 85 porcelain and other varieties according to different Al2O3 content. Sometimes, Al2O3 content of 80% or 75% is also classified as ordinary alumina ceramic series. Among them, 99 alumina ceramic 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; 95 alumina ceramics are mainly used as corrosion-resistant and wear-resistant components; 85 porcelain Due to the fact that part of talc is often added in it, the electrical performance and mechanical strength are improved, and it can be sealed with metals such as molybdenum, niobium and tantalum, and some are used as electrical vacuum device devices.
