Preparation and characterization of (Co0.3Zn0.7)(Ti1-xSnx)Nb2O8 microwave dielectric ceramics.

Zn0.7Co0.3(Ti1-xSnx)Nb2O8 (x = 0.1, 0.15, 0.2, 0.25, 0.3, 0.35) microwave ceramics were prepared by traditional solidstate reaction method. The influences of Sn substituted for Ti on the phase constitution, crystal structure and microwave dielectric properties of Zn0.7Co0.3(Ti1-xSnx)Nb2O8 ceramics were discussed. The XRD patterns revealed the main phase of ZnTiNb2O8 and little content of Zn0.17Ti0.5Nb0.33O2 secondary phase. With further substitution of Sn, the lattice constant, volume and apparent density of the ceramics increased, the ceramic structure reached a maximal compactness at x = 0.2 which was shown on SEM. Tremendous improvement of Q × f and a declining trend of ∊r and τf were obtained with increasing x value. Appropriate substitution value (x = 0.10) would ensure excellent microwave dielectric properties (∊r = 34.1, Q × f = 40562 GHz, τf = -5 ppm/°C) of the ceramics sintered at 1080 °C. [ABSTRACT FROM AUTHOR]