Doping behaviors of Nb2O5 and Co2O3 in temperature stable BaTiO3-based ceramics

The influence of Nb2O5 and Co2O3 on the dielectric constant-temperature characteristic of the Sm2O3, CeO2-doped BaTiO3 system was discussed. It can be concluded that Nb5+, Co3+ will be easier to replace the Ti4+ site by using the Nb2O5-Co2O3 composite oxide than by doping Nb2O5, Co2O3 separately. Increasing Co2O3 amount caused a lower dielectric constant and a higher variation rate. A properly sintering temperature can be helpful to flatten the dielectric constant-temperature curve. The BaTiO3-based ceramics doped with the Nb2O5-Co2O3 composition can be sintered at a temperature as low as 1230-1250 degreesC, and satisfy the X7R required with a high dielectric constant (epsilon(25 degreesC)>4000) and low dielectric loss (tan delta<2.0%). (C) 2002 Elsevier Science B.V. All rights reserved.