Effects of V2O5 Addition on the Microstructure and Microwave Dielectric Properties of ZnNb2O6 Ceramics

ZnNb2O6 ceramics doped with V2O5 were prepared by conventional mixed solid method. The effects of V2O5 addition on the microstructure and the microwave dielectric properties of ZnNb2O6 ceramics were investigated systematically. The sintering temperature of ZnNb2O6 ceramics with 1.0wt.% V2O5 addition can be effectively reduced from 1150 degrees C to 1050 degrees C. The secondary phase ZnV2O6 was observed in sintered samples with V2O5 addition content higher than 1.0wt.%. For 0.3-3wt.%V2O5-doped ZnNb2O6 ceramics, The dielectric constants (epsilon(r)) of densified samples were higher than that of undoped ZnNb2O6 ceramics. The temperature coefficient of resonant frequency (tau(f)) were shifted toward zero direction with the increase of V2O5 addition, However, the dielectric loss (tan delta=1/Q) increased. The 1.0wt.% V2O5-doped ZnNb2O6 ceramics sintered at 1050 degrees for 3h have the optimum microwave dielectric properties: epsilon r=28, tan delta=0.0006 and tau(f)=-42.5 ppm/degrees C.