Low temperature sintering and microwave dielectric properties of Ba3Ti5Nb6O28 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 (TCF) are required for the application of chip passive components in wireless communication low temperature co-fired ceramics (LTCC). In the present study, the sintering behaviors and dielectric properties of Ba3Ti5Nb6O28 ceramics were investigated as a function of B2O3-CuO content. The pure Ba3Ti5Nb6O28 system showed a high sintering temperature (1250 degrees C) and had the good microwave dielectric properties: Q x f of 10,600 GHz, epsilon(r) of 37, TCF of -12 ppm/degrees C. The addition of B2O3-CuO was revealed to lower the sintering temperature of Ba3Ti5Nb6O28, 900 degrees C and to enhance the microwave dielectric properties: Q x f of 32,500 GHz, epsilon(r) of 40, TCF of 9 ppm/degrees C. From the X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction (XRD) studies, these phenomena were explained in terms of the reduction of oxygen vacancies and the formation of secondary phases having the good microwave dielectric properties.