Investigation of Dielectric Properties of BaZr(BO3)2 Ceramics

Abstract

The effects of 3Zn-B2O3, B2O3 and flux additions on the microwave dielectric properties and the microstructures of Ba2Ti9O20-based ceramics have been investigated in our previous study. BaZr(BO3)2 phase existed in the Ba2Ti9O20-based ceramics, and could affect the microwave dielectric properties when the formation of the BaZr(BO3)2 phase is enhanced. In order to understand well the effect of the BaZr(BO3)2 phase on the dielectric properties of Ba2Ti9O20-based ceramics, the BaZr(BO3)2 composition was synthesized by conventional solid-state methods from individual BaCO3, ZrO2 and B2O3 powders. X-ray diffraction (XRD) results show the presence of the mainly crystalline phase, BaZr(BO3)2, and the minor phases are BaZrO3 and ZrO2 in the sintered ceramics. Scanning electron microscopy images show that the BaZr(BO3)2 grain prefers to develop oriented dendrite microstructures. Plots of dielectric loss versus sintering temperatures show a linearity, and ranges from 0.85 (at 1080°C) to 0.08 (at 1250°C). However, the dielectric constant does not increase with increasing sintering temperature, and it's value is maintained at 11–13.