Features of the Preparation and Study of Electrophysical Characteristics (BeO+TiO2)-Ceramics by Impedance Spectroscopy

Аннотация

An electrically conducting two-component BeO-ceramic with the addition of micro- and nano-crystalline TiO₂ powder is prepared that can be used as a material for scattered microwave radiation absorption in high-power electronic devices. The nature of the occurrence of electrical conductivity and absorption of the microwave field in (BeO + TiO₂)-ceramics is not completely established. Impedance spectroscopy is used for the first time to investigate the electrical and dielectric characteristics of this ceramic in the frequency range from 100 Hz to 100 MHz in relation to presence of micro- and nano-sized TiO₂ phase within the BeO ceramic composition. It is established that the static resistance of ceramics with addition of a TiO₂ nanopowder is significantly reduced compared with the resistance of original ceramic with TiO₂ micropowder. It is shown that real and imaginary components of the dielectric constant of the ceramic studied increase to abnormally large values with a reduction in frequency of the effective electric field, and in the high frequency range f ≥ 10⁸ Hz the process of dielectric relaxation commences leading to an increase in dielectric loss angle. Dielectric properties of ceramic samples are determined under blocking conditions for through conduction. The effect of TiO₂ micropowder additions on dielectric polarization processes with frequency increasing up to 12 × 10⁹ Hz is considered.