Research On Temperature Stable Barium Strontium Titanate Dielectric Relaxation Ferroelectric Ceramics

Dielectric temperature-stable material for chip ceramic capacitors has been widely used. With the upgrading of electronic products, it is stricter for the performance of the electronic components. On the other hand, with the promotion of environment-friendly materials, more environmentally friendly, cheaper, superior electronics will gradually replace the existing products. The update of the raw materials and advanced technology are treated as the main way to get the advanced type of material.Theoretical study analyzed the basic principle of the temperature-stable material. By studying the mechanism of defects and composition distribution in Glass transition theory to discuss the possibility of temperature-stable material. Simultaneously, different models, such as relaxor ferroelectric phase transition, the core-shell structure, co-doping effects, as well as the size effects for dielectric-temperature stability of the BST material were analyzed.Chemical homogeneity doping and inhomogeneity doping were used respectively to modify barium strontium titanate materials. Trivalent and pentavalent oxides were selected for complex dopants. Y-Nb-doped composite was found to be able to substantial increase in the BST dielectric constant, furthermore, semiconductor effect was found when the Y/Nb is greater than21/9. Broadening effect of dielectric-temperature relationship was observed in La-Nb ion doped BST with smaller dielectric constant. Bi-Nb composite has a significant impact on the phase transition temperature of the material. When the doping ratio Bi/Nb=21/9, relatively stable dielectric temperature relationship was revealed in BST.Experiment with Y as chemical homogeneity dopant, Nb was doped as chemically ingomogeneity to modified BST. Ceramics, meet the standard of EIAX7R, was obtained with dielectric constant higher than4300and loss tangent less than0.025at room temperature. Even in the common temperature range, the material, meet the standard of Z5E and Z6P in EIA, with dielectric temperature stable performance better than the similar products, has a great potential market value. In addition, it has a certain significance that the sodium bismuth titanate and barium strontium titanate co-fired ceramic material with a better temperature stability was investigated for its two-phase coexistence.