Fabrication and microstructure investigation of ultra-high-strength porcelain insulator

Insulators are essential components of power transmission network. With natural minerals such as bauxite and clay, we have fabricated ultra-high-strength porcelain insulator (UHSPI) of electromechanical failure load 420 kN determined by International Electrotechnical Commission (IEC), and have put it into production. Compared with other UHSPI fabricating methods, in which industrial alumina is used, our method is cost saving and rich in resources. The main objective of the study is to elucidate the relationship between microstructure (e.g. size, amounts and distribution of particles) and mechanical property of the sintered UHSPI and thereby to explore a way to further improve the mechanical property of UHSPI. The investigations of SEM, EDAX and XRD reveal that the strengthening mechanisms may be the combination of matrix reinforcement, mullite reinforcement and dispersion strengthening; high porosity (9.9%) and abnormal pores are more possible to be the main factor hindering electromechanical property improvement.