Microstructure and dielectric properties of Ba0.4Sr0.6Ti1-yZryO3 sintered with SrO-B2O3-SiO2 glass additive

Ba0.4Sr0.6Ti1-yZryO3 (0 <= y <= 0.20) (BSTZ) ceramics were prepared via the solid state reaction route, followed by sintering at high temperature. SrO-B2O3-SiO2 glass, as the sintering additive, was introduced to lower the sintering temperature. The effects of the amount of Zr substitution for Ti in Ba0.4Sr0.6Ti1-yZryO3 on the sintering temperature, microstructure and dielectric properties were investigated. Sintering temperature of Ba0.4Sr0.6Ti1-yZryO3 increases gradually with the increasing amount of Zr in Ba0.4Sr0.6Ti1-yZryO3. XRD phase analysis shows that all samples exhibit the desired perovskite structure, where the cell parameter a increases with the increasing amount of Zr substitution. Microstructural studies reveal a slow-down in grain growth by Zr substitution. Dielectric relaxation is observed in the dielectric loss versus temperature plots, where the relaxation time shows an increase with the increasing amount of Zr substitution. The slow-down in grain growth gives rise to the formation of more grain boundaries, which restrict the charge spreading and lead to an increase in the grain boundary barrier E-a,E- 2. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.