Influence of V_2O_5 on the Properties of BaTiO_3-Y_2O_3-MgO Ceramics

The microstructure and dielectric properties of V_2O_5-doped BaTiO_3-Y_2O_3-MgO ternary system were studied.SEM shows that V ions can promote grain growth of BaTiO_3 based ceramics, but decrease the density of sintered ceramics.XRD indicates that V-doped samples have pseudocubic structure and the solubility limit of V is more than 1.0mol%.The results show that V can increase the intensity of Curie peak and improve the temperature stability of dielectric constant,because of the formation of core-shell-grains with thin shell layer,which is attributed to the fact that V ions can effectively inhibit the diffusion of Y and/or Mg ions into BaTO_3 grains and change the distribution of doping ions in the grains.Moreover multivalent V ions can reinforce the nonreducibility of this system, and the insulation resistivity increases to 10~(13)Ω·cm and dielectric loss decrease to 0.63% consequently. The high performance materials with dielectric constant of 2600 satisfying the X8R requirement is achieved when 0.1mol% V is added.