Abstract:

The microstructure and dielectric properties of V₂O₅-doped BaTiO₃-Y₂O₃-MgO ternary system were studied. SEM shows that V ions can promote grain growth of BaTiO₃ 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 BaTO₃ 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 10¹³Ω·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.

Key words: BaTiO3, V2O5, microstructure, dielectric properties, multilayer ceramic capacitor