Alumina ceramics (used to be divided into 75 ceramics, 95 ceramics, 99 ceramics, etc.) and steatite (magnesium silicate partial) which have the function of high mechanical strength, good insulation properties, also with high temperature resistance, corrosion resistance, small dielectric loss and dielectric constant, was widely used in electronic appliances, electronic components, electronic machine for insulation, loading，support, connection and so on. Special ceramics is currently the largest, most widely used material in ceramic industry.