What are the main components of alumina ceramics

Alumina ceramic is a kind of ceramic material with alumina (Al₂O₃) as the main body, which is used in thick film integrated circuits. Alumina ceramics have good conductivity, mechanical strength and high temperature resistance. It should be noted that ultrasonic washing is required. Alumina ceramics are widely used ceramics. Because of its superior properties, it has been more and more widely used in modern society to meet the needs of daily performance.

Alumina ceramics are divided into high-purity type and ordinary type.

High purity alumina ceramics are ceramic materials with Al₂O₃ content of more than 99.9%. 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; Using its light transmittance and alkali metal corrosion resistance as sodium lamp tube; It can be used as integrated circuit substrate and high frequency insulating material in electronic industry.

Ordinary alumina ceramics are divided into 99 porcelain, 95 porcelain, 90 porcelain, 85 porcelain and other varieties according to different Al₂O₃ content. Sometimes those with Al₂O₃ content of 80% or 75% are also classified as ordinary alumina ceramics series. Among them, 99 alumina ceramic materials are used to make high-temperature crucibles and refractory furnace tubes, such as ceramic bearings, ceramic seals and water valve plates; 95 alumina porcelain is mainly used as corrosion-resistant parts; Because some talc is often mixed in 85 porcelain, the electrical properties and mechanical strength are improved. It can be sealed with molybdenum, niobium, tantalum and other metals. Some are used as electric vacuum devices.

The molding methods of alumina ceramic products include dry pressing, grouting, extrusion, cold isostatic pressing, injection, casting, hot pressing and hot isostatic pressing. In recent years, domestic and foreign molding technology has been developed, including pressure filtration molding, direct solidification casting, gelcasting, centrifugal casting and solid free molding. Different product shapes, sizes, complex modeling and precision products need different molding methods.