Porcelain insulator includes steel cap, porcelain piece, steel foot and other parts, among which porcelain piece is the part bearing the insulation, early porcelain insulator porcelain piece raw material is siliceous porcelain, with quartz, feldspar, clay as the raw material, forming porcelain components including quartz, mullite, pore and glass phase. The composition of quartz is SiO2, and the chemical property is stable. The composition of mullite is aluminosilicate, which has good heat resistance and small thermal conductivity. The mechanical strength of the ceramics can be improved by adjusting the quartz content and internal crystal structure after sintering.
The difference between high alumina ceramics and siliceous ceramics is that alumina content is higher (industrial alumina is added), corundum (alumina) content in fired high alumina ceramics can reach 30% - 45% or even higher, particles are more uniform, so as to obtain higher mechanical strength and better thermal stability and arc resistance.