Improvements in the sintering and microwave properties of BiNbO4 microwave ceramics by V2O5 addition

The effects of V2O5 on the phase formation and the microwave dielectric properties of BiNbO4 ceramics were investigated as a function of the amount of V2O5. As the amount of V2O5 addition increased from 0.125 to 1 wt%, the densification temperatures of BiNbO4 ceramics decreased from 960 to 900°C. For densified BiNbO4 ceramics, as the amount of V2O5 increased from 0.125 to 1 wt% V2O5 added, the dielectric constants decreased from 43.7 to 43.4 and the temperature coefficients (τf) increased from +2.8 to +19.5 ppm/°C. The quality values (Q) of V2O5-doped BiNbO4 ceramics first increased, reached a maximum at 0.5 wt% V2O5, and then decreased with the further increase amount of V2O5 addition. The 0.5 wt%-V2O5-doped BiNbO4 ceramics sintered at 960°C had the optimum microwave dielectric properties: εr=43.6, τf=+13.8 ppm/°C, and Q=3410.