Preparation and microwave dielectric properties of Li3(Mg0.92Zn0.03)2NbO6-Ba3(VO4)2 composite ceramics for LTCC applications

In this work, the (1 - x)Li-3(Mg0.92Zn0.08)(2)NbO6-xBa3(VO4)(2) (x= 0.1-0.35) ceramics were prepared via a conventional solid state reaction route. The phase composition, microstructure and microwave dielectric properties were investigated by an X-ray diffractometer (XRD), a scanning electron microscope and a network analyzer. The XRD results indicated that the Li-3(Mg0.92Zn0.08)(2)NbO6 and Ba-3(VO4)(2) phases could well coexist without forming any secondary phases. The dielectric constant (Er) and quality factor (Q x f) values of the Li-3(Mg0.92Zn0.08)(2)NbO6 ceramic decreased with the addition of Ba-3(VO4)(2) phase, however its temperature coefficient of resonant frequency (tau(f)) value was improved significantly. Excellent microwave dielectric properties of epsilon(r) similar to 16.3, Q x f similar to 50,084 GHz (at 8.64 GHz) and tau(f) similar to 1.5 ppm/degrees C were achieved for the x= 0.3 sample when sintered at 950 degrees C for 4 h. The chemical compatibility with Ag electrode indicated that the 0.7Li(3)(Mg0.92Zn0.08)(2)NbO6-0.3Ba(3)(VO4)(2) composite ceramic would be a promising material for the low temperature cofired ceramic applications. (C) 2015 Elsevier Ltd. All rights reserved.