Effect of BaO-Al2O3-B2O3-SiO2 glass additive on densification and dielectric properties of Ba0.3Sr0.7TiO3 ceramics

To fabricate the energy storage ceramics with large sizes for pulsed power transmission line, the densification behavior and dielectric properties of Ba0.3Sr0.7TiO3 with 0-8 mass% BaO-Al2O3-B2O3-SiO2 glass additive were investigated. With increasing glass content, both the densification temperature and densification rate decreased remarkably. The shrinkage rate mismatch caused by green density gradient also reduced remarkably, which contributed to the fabrication of large sizes of ceramic with dense microstructure. The additions of glass phase decrease the dielectric constant. However, the breakdown strength of the samples can be increased by a factor of 1.5 over the pure BST because of the modification of the microstructure. For the samples containing 4 mass% glass additions, optimal dielectric properties were obtained: dielectric constant is 440, dielectric loss is 3.5 x 10(-3) at 1 MHz, and breakdown strength is 16.4 kV/mm.