Effect of Dy_2O_3 doping on microstructure, electrical and dielectric properties of ZnO-V_2O_5-based varistor ceramics

摘要

The effect of Dy_2O_3 doping on the microstructure, electrical and dielectric properties of ZnO-V_2O_5-based varistor ceramics was systematically investigated. The average grain size decreased from 5.5 to 5.2 μm to a small extent until the amount of the doped Dy_2O_3 reaches 0.1 mol%. The sintered densities of the doped samples also increased from 5.51 to 5.58 g/cm~3 to a small extent with increasing Dy_2O_3 amount. The breakdown field increased from 4552 to 5117 V/cm until the amount of the doped Dy_2O_3 reaches 0.1 mol%. The sample doped with 0.1 mol% Dy_2O_3 exhibited good non-ohmic properties: 53.3 in the non-ohmic coefficient, and 0.21 mA/cm~2 in the leakage current density. In addition, the dielectric constant and dissipation factor exhibited a minimum value, 713.1 and 0.205 at 0.1 mol%, respectively.