The effect of sintering atmosphere on the microwave dielectric properties of V2O5 doped BiNbO4 ceramics

Sintering behavior and microwave dielectric properties of BiNbO4 doped with V2O5 sintered under ambient and N2 atmosphere were investigated. The densification temperature and dielectric constant of BiNbO4 fired under ambient atmosphere decreased from 975 to 850 °C and 45.6 to 42.2, respectively, as the amount of V2O5 increased from 0.1 to 3.2 mol%. BiNbO4 ceramics was very sensitive to low oxygen partial pressure atmosphere and can be severely reduced under H2 atmosphere. The apparent density of ceramics sintered under high purity N2 was smaller than that sintered under ambient atmosphere due to the production of vacancies defects. The formation of oxygen vacancies did not change the crystal structure or decay microwave properties. On the contrary, better microwave properties: ϵr=42.7, Qf=28,500 were gotten when BiNbO4 ceramics with 0.8 mol% V2O5 additives sintered under N2 atmosphere.