A new temperature stable microwave dielectric ceramics: ZnTiNb2O8 sintered at low temperatures

The phases, microstructure and microwave dielectric properties of ZnTiNb2O8-xTiO(2) composite ceramics with different weight percentages of BaCu(B2O5) additive prepared by solid-state reaction method have been investigated using the X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results showed that the microwave dielectric properties were strongly dependent on densification, grain sizes and crystalline phases. The sintering temperature of ZnTiNb2O8 ceramics was reduced from 1250 degrees C to 950 degrees C by doping BaCu(B2O5) additive and the temperature coefficient of resonant frequency (tau(f)) was adjusted from negative value of -52 ppm/degrees C to 0 ppm/degrees C by incorporating TiO2. Addition of 2 wt% BaCu(B2O5) in ZnTiNb2O8-xTiO(2) (x = 0.8) ceramics sintered at 950 degrees C showed excellent dielectric properties of epsilon(r) = 38.89, Qxf = 14,500GHz (f = 4.715 GHz) and tau(f) = 0 ppm/degrees C, which represented very promising candidates as LTCC dielectrics for LTCC applications. (C) 2011 Published by Elsevier B.V.