Effects of B2O3 addition on the structural and dielectric properties of 0.7BaTiO(3)-0.3 CaTiO3 ceramics

摘要

The effects of B2O3 addition on the structural and dielectric properties of (0.7) BaTiO3-0.3CaTiO(3) composite materials were investigated. (0.7) BaTiO3-0.3CaTiO(3)-y B2O3 (0 <= y <= 3 mol. %) pellets were prepared from BaTiO3 (BT) and CaTiO3 (CT) powders mixture and sintered. The obtained results pointed out three distinct domains in the evolution of the relative density as a function of mol. % B2O3. Hence, in pellets containing between 0 and 1 mol. % B2O3 an important increase in the relative density is remarked for all sintering temperatures. In the second domain corresponding to pellets containing between 1 and 2 mol. % B2O3, the densification rate was clearly less important. In the third domain corresponding to mol. % B2O3 >2, a decrease in densification was observed for all considered temperatures. X-rays diffraction (XRD) analysis revealed the presence of BT and CT solid solutions together with an unknown secondary phase. Furthermore, XRD patterns revealed a net decrease in the CT proportion with added of mol. % of B2O3, while, the proportion of the unidentified phase increased.