The Effect of B2O3-Li2CO3 Addition on Sintering Behavior and Dielectric Properties of Ba0.6Sr0.4TiO3 Ceramics

Barium strontium titanate (Ba0.6Sr0.4TiO3: BST) powders were prepared by the oxalate co-precipitation method. The ceramics from thus obtained BST powders with B2O3-Li2CO3 addition were prepared by conventional oxide mixing method. The powders and the ceramics were observed and analyzed by SEM and X-ray diffraction. The effects of B2O3-Li2CO3 addition and powder properties on the sintering behavior and the dielectric properties of BST-based ceramics were investigated. SEM results revealed that the BST powders are micron-sized with cauliflower-shaped rough surface leading the specific surface area reaches 18.52m(2)/g. In dilatometric studies, the ceramics without B2O3-Li2CO3 addition didn't produce the desired shrinkage and dense microstructure at relative low temperatures (<1000 degrees C). However, the sintering temperature is decreased to 850 degrees C by addition of small amount (<= 3wt %) of B2O3 and Li2CO3. This was also verified in sintered microstructures. The XRD results showed that the main phase of the ceramics was BST without any other crystalline phases of remarkable extent. With increasing of B2O3-Li2CO3 content, the permittivity and the tunability of the ceramics were decreased.