Electronic Properties of BZT Nano-Ceramic Grades at Low Frequency Region

Abstract

Barium zirconium titanate ceramics were prepared using solid state reactions of BaCO3, TiO2 and ZrO2 at elevated temperatures. The prepared BZT was mechanically activated in the planetary ball mill from 0-120 min to achieve different powder grades from micro- to nanosized particles. After the powder characterization by XRD and SEM the samples were pressed in disc shape and sintered at 1100 and 1200 °C in the air. The sintered samples were characterized by SEM. After that the silver epoxy electrodes were deposited on sintered disc samples. The disc samples capacitance and resistivity were measured in the low frequency region from 1 Hz to 200 kHz using a low frequency impedance analyzer. Sintering temperatures and powder grades were used as parameters. Finally, specific resistance ρ, dielectric permittivity (ε' + jε") and tgδ were obtained from the impedance measurements. The trends in electronic properties were analyzed: the relaxation effect of the space charge (inter-granular electric charges) vs. sintering temperature and ceramic grades. These show that mechanical activation has a significant effect on electrical properties, resulting in generally improved overall performance.