BT-30 Ceramic Electrophysical Properties

Abstract

A total complex resistance (impedance) method is used to study the electrophysical characteristics of (BeO + TiO2)-ceramics modified with TiO2 micro- and nanoparticles in an amount of 30 wt.% (BT-30). Dispersion of the actual e′ and imaginary e′′ components of the dielectric permittivity component and specific conductivity in the frequency range from 100 Hz to 100 MHz from room temperature to the boiling point of liquid nitrogen are determined. High values of e′ and e′′ in the low-frequency range are typical for structurally inhomogeneous materials due to the accumulation of electric charges at the surface and within microcrystals. Two dielectric relaxation processes associated with electrical conductivity within the body and at the surface of ceramics are detected for the first time. An increase in conductivity with an increase in the microwave field frequency above 1 MHz is explained by the appearance of a current relaxation component. The activation energy of the static resistance of ceramic specimens is determined as a function of the reciprocal temperature that depends little on the weight content of TiO2 nanoparticles and varies in the range of 0.024 – 0.10 eV This also confirms the existence of two independent conduction processes, weakly dependent on the nanoparticle content in the ceramic composition. With placement of ceramic in a high-frequency electric field, spatial charges are formed, the field of which contributes to creation of additional polarization and dielectric losses.