Effect of glass additions on the sintering and microwave properties of composite dielectric ceramics based on BaO-Ln_2O_3-TiO_2 (Ln velence Nd, La)

摘要

Ten weight percent BBZS (Bi_2O_3, B_2O_3, ZnO and SiO_2) glass was added to x(Ba_4Nd_(9.333)Ti_(18)O_(54)) -(1 -x)(BaLa_4Ti_4O_(15)) (BNLT, 0 < = x < = 1) composite dielectric ceramics to lower their sintering temperature whilst retaining microwave properties useful for low temperature co-fired ceramic and antenna core technology. With the addition of 10 wt percent BBZS glass, dense BNLT composite ceramics were produced at temperatures between 950 and 1140 deg C, depending on composition (x), an average reduction of sintering temperature by 350 deg C. X-ray diffraction, scanning and transmission electron microscopy and Raman spectroscopy studies revealed that there was limited inter-reaction between BLT/BNT and the BBZS glass. Microwave property measurement showed that the addition of BBZS glass to BNLT ceramics had a negligible effect on epsilon_r and tau_f, although deterioration in the measured quality factor (Qf) was observed. The optimised composition (xBNT - (1 - x)BLT)/0.1BBZS (x velence 0.75) had epsilon_r approx 61, tau_f approx 38 ppm/ deg C and Qf approx 2305 GHz.