Effects of additives on microstructures and microwave dielectric properties of (Zr, Sn)TiO₄ ceramics

The effects of CuO, Bi₂O₃ and V₂O₅ additives (up to 3 wt.%) on the microstructures and the microwave dielectric properties of (Zr_0.8Sn_0.2)TiO₄ ceramics are investigated. The sintering temperature of (Zr_0.8Sn_0.2)TiO₄ ceramics with CuO, Bi₂O₃ and V₂O₅ additions can be effectively reduced from 1400 to 1300°C due to the liquid phase effects. The grain grows at lower sintering temperatures (1300°C) to 4.5-5.4 μm with CuO, Bi₂O₃ or V₂O₅ additions. The dielectric constants (ε_r) are not significantly affected by various additives and ranged in 36-38. Small values (<±3 ppm°C^-1) of the temperature coefficient of resonant frequency (τ_f) are obtained for (Zr_0.8Sn_0.2)TiO₄ ceramics with additives. However, the unloaded quality factors Q × f are strongly dependent upon the type and the amount of additives.