Effect of V₂O₅ and CuO additives on sintering behavior and microwave dielectric properties of BiNbO₄ ceramics

The influences of V₂O₅ and CuO additives on the sintering behavior and microwave dielectric properties of BiNbO₄ ceramics were investigated. The V₂O₅ and CuO additives lowered the sintering temperature of BiNbO₄ ceramics to the range 875 °C-935 °C. All BiNbO₄ compounds with additives had the orthorhombic structure. The dielectric constant ε_r was not significantly changed, while the unloaded Q value was affected with additives. The Qf value was found to be a function of the sintering temperatures and the amount of additives. It varied from 4500 to 15800 (GHz) and 1000 to 8000 (GHz) with additives V₂O₅ and CuO, respectively. The τ_f values were increased in positive values with V₂O₅ doped, while decreased in negative values with CuO addition. V₂O₅ and CuO additives effectively improved the densification and dielectric properties of BiNbO₄ ceramics. The correlation between the microstructure and the Qf value was observed with different additives.