Microwave dielectric properties and low-temperature sintering of Ba3Ti4Nb4O21 ceramics with B2O3 and CuO additions

Abstract

The low sintering temperature and the good dielectric properties such as high dielectric constant (epsilon(r)), high quality factor (Q x f) and small temperature coefficient of resonant frequency (tau(f)) are required for the application of chip passive components in the wireless communication technologies. In the present study, the sintering behaviors and dielectric properties of Ba3Ti4Nb4O21 ceramics were investigated as a function of B2O3-CUO content. Ba3Ti4Nb4O21 ceramics with B2O3 orCuO addition could be sintered above 1100 degrees C. However, the additions of both B2O3 and CuO successfully reduced the sintering temperature of Ba3Ti4Nb4O21 ceramics from 1350 to 900 degrees C without detriment to the microwave dielectric properties. From the X-ray diffraction (XRD) studies, the sintering behaviors and the microwave dielectric properties of low-fired Ba3Ti4Nb4O21 ceramics were examined and discussed in the formation of the secondary phases. The Ba3Ti4Nb4O21 sample with 1 wt% B2O3 and 3 wt% CuO addition, sintered at 900 degrees degrees C for 2 h, had the good dielectric properties: epsilon(r) = 65, Q x f 16,000 GHz and tau(f) = 101 ppm/degrees C. (C) 2007 Published by Elsevier Ltd.