Low-temperature sintering and microwave dielectric properties of Ba5Nb4O15 with ZnB2O4 glass

Abstract

The Influence of ZnB2O4 glass addition on the sintering temperature and microwave dielectric properties of Ba5Nb4O15 has been investigated using dilatometry, X-ray diffraction, scanning electron microscopy and network analyzer. It was found that a small amount of glass addition to Ba5Nb4O15 lowered the sintering temperature from 1400 to 900 degrees C. The reduced sintering temperature was attributed to the formation of ZnB2O4 liquid phase and B2O3-rich liquid phases such as Ba3B2O6. The Ba5Nb4O15 ceramics with ZnB2O4 glass, sintered at a low temperature, exhibited good microwave dielectric characteristics, i.e., a quality factor (Q x f) = 12,100 GHz, a relative dielectric constant (epsilon(r)) = 40, a temperature coefficient of resonant frequency (tau(f)) = 48 ppm/degrees C. The dielectric properties were discussed in terms of the densification of specimens and the influence of glassy phases such as Ba3B2O6 and ZnB2O4. (c) 2005 Elsevier Ltd. All rights reserved.