Microwave dielectric properties of BiNbO4 ceramics with CuO–V2O5 addition

BiNbO4 ceramics were developed by using CuO–V2O5 as a liquid phase sintering agent. The resultant dielectric properties were analyzed in terms of the densification and the amount of CuO–V2O5 sintering agent. The addition of 0.8 wt.% CuO–V2O5 as its sintering agent was observed to perform most satisfactory. At 850 °C, uniform and enhanced microstructure was observed for the BiNbO4 specimen with 0.8 wt.% CuO–V2O5 addition. Furthermore, the effect of CuO–V2O5 addition on the microwave dielectric properties of BiNbO4 was also investigated. As the sintering temperature increased to 900 °C, the dielectric constant increased but nearly constant and the quality factor (QF) showed a maximum at 850 °C and then decreased for all compositions of the 900 °C sintered specimens. With an increase in CuO–V2O5 content, the temperature coefficient of frequency (TCF) increased in accordance with the dielectric mixing rule and microstructural behavior.