Comparative microstructure study of high strength alumina and bauxite insulator

The property of insulators is closely related to microstructures. In order to study the difference and similarity of two kinds of insulators microstructure and thereby explore ways to improve the property of insulators further, a comparative study was carried out on three high strength porcelain insulators by XRD, SEM and ceramography. The results indicate that there exists a negative linear relationship between the porosity and the content of amorphous phase. Porosity is the main factor affecting the density of insulator body. Compared with alumina, the calcined bauxite used as raw material will cause the increase of porosity. Microcracks usually appear in vitrified area and area around quartz particle where mullite is rare, crack is obvious. Decreasing the amount of quartz in raw material and increasing the amount of mullite in vitrified area could improve the mechanical strength of porcelain insulators further.