Microwave dielectric properties and structure of ZnO-Nb2O5-TiO2 ceramics

Ceramic samples based on ZnO-Nb2O5-TiO2 compositions have been prepared using solid state ceramic route. The work was carried out over a wide range of initial ZnNb2O6 and Zn0.17Nb0.13Ti0.5O2 compounds concentration. The crystal structure and microstructure developments were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that the phase compositions of the samples present itself a columbite type and mixture of two phases solid solutions of columbite and rutile types. The sintering behavior, permittivity, its temperature coefficients and quality factor had been characterized for ceramic samples in depending on compositions. The permittivity of the samples in this system is within the limits from 24 to 80, tau(epsilon), from 150 to -560 ppm/degrees C. For the samples with tau(epsilon) similar to 0, epsilon(r) similar to 43.8 and Q.f = 35000 GHz at f = 9 GHz. The comparatively low sintering temperature (<= 1080 degrees C) and high dielectric properties in microwave range make these ceramics promising for application in electronics. (C) 2010 Elsevier Ltd. All rights reserved.