Study of Structural and Electrical Properties of Conventional Furnace and Microwave-Sintered BaZr0.10Ti0.90O3 Ceramics

Structural, dielectric, piezoelectric, and ferroelectric properties of Zirconium-doped barium titanate (BaZr0.10Ti0.90O3) ceramics prepared by microwave (MWS) and conventional (CS) sintering process are compared. X-ray diffraction and Raman spectroscopy indicate clearly the structural changes and confirm the effective diffusion of zirconium with the MWS technique to form BZT. Scanning electron microscopy reveals a fine grain, and a dense microstructure in the MWS ceramics processed under 4 h of cycle time (including heating, cooling, and holding time) in comparison with CS requiring 22 h. At room temperature the microwave sintered samples exhibit improved electrical properties exhibiting higher resistivity, higher dielectric constant, a lower dielectric loss, and a reduced dependence on frequency. Impedance and electric modulus spectroscopy analysis in the frequency range (40 Hz-1 MHz) and high-temperature range (573-873 K) suggests two relaxation processes attributed to bulk and grain boundary effects in the impedance plots for the both MWS and CS ceramics. The microwave-sintered BZT ceramics are found to be more attractive for room temperature device applications with improved properties, however, at higher temperatures they tend to degrade in comparison with the CS ceramics.