Microwave dielectric properties and structure of ZnO-Nb_2O_5-TiO_2 ceramics

摘要

Ceramic samples based on ZnO-Nb_2O_5-TiO_2 compositions have been prepared using solid state ceramic route. The work was carried out over a wide range of initial ZnNb_2O_6 and Zn_(0.17)Nb_(0.33)Ti_(0.5)O_2 compounds concentration. The crystal structure and microstructurc 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 ty pes.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, r￡ from 150 to -560ppm/°C. For the samples with τ_ε ～ 0, ε_r ～ 43.8 and Q.f= 35000 GHz at f= 9 GHz. The comparatively low sintering temperature (<1080°C) and high dielectric properties in microwave range make these ceramics promising for application in electronics.