Alumina ceramics (alumina ceramics) is a kind of ceramics with the main crystal of mouth-A12 03. For thick film integrated circuits. Alumina ceramics have good conductivity, mechanical strength and high temperature resistance. It should be noted that ultrasonic washing is needed. Alumina ceramics are widely used. Because of its superior performance, it has been more and more widely used in modern society to meet the needs of daily use and special performance. At present, alumina ceramics are divided into two types: high purity type and common type. High purity alumina ceramics containing more than 99.9% Al2O3 are usually made into molten glass instead of platinum crucible because of their sintering temperature as high as 1650-1990 C and transmission wavelength as 1-6 um. They are used as sodium lamp tubes by their light transmittance and alkali-resistant corrosion resistance, and as IC substrates in the electronic industry. High frequency insulation material. Ordinary alumina ceramics can be classified into 99, 95, 90 and 75 kinds according to the content of Al2O3. Sometimes, those with Al2O3 content of 80% or 75% are classified as ordinary alumina ceramics.