Structure–property relationship in high-tension ceramic insulator fired at high temperature

Ceramic insulators are widely used in microelectronic devices. In this paper, the mechanical and electrical properties of porcelain ceramic insulator fired at 1350 °C have been investigated along with microstructural characterization using scanning electron microscopy (SEM) in order to understand the structure–property relationship of ceramic insulator. The bending and the dielectric strength were measured on various samples fired at 1350 °C. The bending strength (757.3 kg/cm2) and the dielectric strength (28.36 kV/mm) was found short of the desired value. The microstructural features developed clearly describe why the dielectric strength and the bending strength are not up to the mark. EDAX analysis, X-ray fluorescence (XRF) and X-ray diffractometry (XRD) techniques were also done to support the results. XRD pattern shows 70% mullite and 20% quartz peak intensity and the XRF results shows 22.64% Al2O3 that indicates low mullite formation and hence it is confirmed that it is mullite, the crystalline phase, which contribute together with quartz particle to the dielectric and mechanical strength. SEM image shows large number of microcracks that also hinder the high electrical and mechanical properties of porcelain ceramic insulator.