Study On Processing Methods And Dielectric Properties Of (Ba, Sr)TiO₃ Based Ceramics For High Energy Storage

High dielectric constant(ε_r)and high breakdown strength(E_b)of the ceramics were the important research field of dielectric materials.How to deal with the three department relation was very important to improve the energy storage density of ceramics.In this paper,the dielectric properties of SrTiO₃-based ceramics with BaTiO₃ and SrZrO₃ additions were investigated for improving dielectric constant and breakdown strength.It aimed to produce a high dielectric constant and low dielectric loss and high breakdown strength ceramic for storage energy.In this paper,the dielectric properties and microstructures of Ba_0.3Sr_0.7(Zr_xTi_1-x)O₃ ceramics system(x=0.025,0.050,0.075,0.100,0.150,0.200)were investigated.A single-phase structure was obtained for all compositions.The unit-cell volume of all compounds increased as x increasing.For Ba_0.3Sr_0.7(Zr_xTi_1-x)O₃ ceramics system,as x value increased from 0.025 to 0.200,the ceramics system kept cubic by using program X'Pert HighScore Plus.(Ba,Sr)TiO₃ ceramics system with SrZrO₃ addition can be sintered to 95%of the theoretical density.At frequency 1MHz,The dielectric constant value of Ba_0.3Sr_0.7(Zr_xTi_1-x)O₃ ceramics increased from 610 to 680 with the x increased from 0.025 to 0.150,and when x increased to 0.200,the dielectric constant decreased slightly.With the x value increased from 0.025 to 0.200,the dielectric loss value had a slightly changed,but keeping at 1×10^-3,and the BDS value increased first and then decreased with x value increasing.When x value was 0.025,the BDS value was 4.63kV/mm.When x value was 0.150,the BDS value was 5.40kV/mm.These results could be explained by the effect of density,grain size,defects on the dielectric properties of the specimens.Then this paper introduced the breakdown mechanisms of the ceramic.A statistical approach is used to determine the effect of porosity in Ba_0.3Sr_0.7TiO₃ material on their dielectric breakdown strength,and founded that the breakdown mechanisms of the Ba_0.3Sr_0.7TiO₃ ceramic was weakness breakdown mechanisms.