ELECTRICAL AND DIELECTRIC PROPERTIES OF THERMALLY GROWN OXIDE (TGO) ON FECRALLOY SUBSTRATE STUDIED BY IMPEDANCE SPECTROSCOPY

摘要

Thermally grown oxide (TGO) formed on Fecralloy substrate exposed to an oxidizing environment of 1100°C for 4 hours was characterized by impedance spectroscopy method. Electrical and dielectric properties of TGO were investigated. AC conductivities and dielectric constants were studied as a function of frequency and temperature. AC conductivity analysis indicates a change in conduction mechanism around 400°C. Dielectric constant shows remarkable dispersions at low frequencies and high temperatures, which is considered to be originated from the Maxwell-Wagner type polarization from the interface of grain and grain boundary.