Ba_(0.7)Sr_(0.3)TiO_3-glass-silver percolative composite

摘要

Ba_(0.7)Sr_(0.3)TiO_3-glass-silver (BST-glass-Ag) composites were prepared by the solid state ceramic route. Their percolation behavior and dielectric properties were examined. The pure BST had a percolation limit of 24 vol% of silver whereas an addition of 8 wt% of 50PbO-30B_2O_3-20SiO_2 (PBS) glass lowered the percolation limit to 14 vol% of Ag. Glass addition lowered the sintering temperature of BST from 1300 to 975 °C and addition of Ag further lowered the sintering temperature to 925 °C, minimizing the Ag loss during sintering. The relative permittivity increased from 2700 for pure BST to about five orders of magnitude in the BST-glass-Ag composites near the percolation threshold.