Preparation of BaTiO3-based X7R ceramics with high dielectric constant by nanometer oxides doping method

High performance X7R dielectric materials were prepared by doping Nb2O5-Co3O4 nanometer composite oxide to BaTiO3 powders, with a dielectric constant as high as 5200 and dielectric loss lower than 1.0%, when they were sintered at 1300 for 2 h. The effect of Nb2O5-Co3O4 nanometer composite oxide was discussed. It was concluded that Nb5+, Co3+ were easier to incorporate into BaTiO3 lattice by using Nb2O5-Co3O4 nanometer composite oxide as dopants than by doping Nb2O5, Co3O4 separately. It was favorable by nanometer oxides doping to make the system hold high dielectric constant and still satisfy the requirement of ElA X7R specification, attributed to the uniform distribution of nanometer dopants in BaTiO3 grain boundaries and the formation of abundant "core-shell" structure with relatively thinner grain shell. (C) 2004 Elsevier B.V. All rights reserved.