Dielectric and energy storage properties of barium strontium titanate based glass-ceramics prepared by sol-gel method

Ba0.6Sr0.4TiO3 based glass-ceramics were prepared by sol-gel process. Influences of B-Si-O glass content on the microstructure, dielectric, and energy storage properties of the BST based glass-ceramics have been investigated. Perovskite barium strontium titanate phase was found at annealing temperature 800 A degrees C. A secondary phase Ba2TiSi2O8 was detected and lowered by declining the mole ratio of element Si (from 50 to 25 mol%) in glass additive. Microstructural observation indicated that the microstructure homogeneity can be improved by glass addition till 2 mol%, while worsened by excessive glass concentrations. Due to relatively homogeneous microstructure, the maximum discharged energy density and breakdown strength were also obtained in samples with 2 mol% glass additive, which were found to be 0.553 J/cm(3) and 43.2 kv/mm, respectively. Microscopic observation of the breakdown area was performed and the mechanical failure, including the formation and accumulation of micro-cracks during the dielectric breakdown process, was considered to be the main cause of dielectric breakdown. Results of the charging and discharging energy densities show that the BST based glass-ceramics prepared by sol-gel method has a potential for pulse power applications.