Influence of glass additives on the sintering behavior and dielectric properties of BaO•(Nd0.8Bi0.2)2O3•4TiO2 ceramics

Effects of various glasses (Bi2O3-B2O3-ZnO-SiO2 (BBXSZ, where X = the mole fraction of Bi2O3 in the glass) glasses with different Bi2O3 content) on both the sintering behavior and microwave dielectric properties of BaO center dot(Nd1-xBix)(2)O-3 center dot 4TiO(2) (BNBT) ceramics were investigated in developing low-temperature-fired dielectric ceramics for microwave devices. Glass wetting characteristics on the BNBT surface, X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and a dilatometer were used to examine the effect of various glasses on BNBT densification and the chemical reaction between the glass and BNBT. The results indicate that BB25SZ glass can be used as a sintering aid to reduce the densification temperature of BNBT from 1300 to 900 degrees C without secondary phase formation. BNBT ceramics with 20 wt.% BB25SZ glass sintered at 900 degrees C show a relative density of 92%, a high-dielectric-constant of 84, a quality factor (Qxf) of 2999, and a temperature coefficient of resonant frequency of 23.7 ppm/degrees C. (C) 2007 Elsevier B.V. All rights reserved.