| In an effort to developing ceramic dielectrics with high energy density for compact pulsed power application, the properties of these ceramics that must possess high dielectric constant( εr ), low dielectric loss( tan δ ) and high breakdown strength( Eb) are required. In this work, the dielectric properties of SrTiO3-based ceramics with SrZrO3 and Bi2O3 · TiO2 additions were investigated for high energy density application.The dielectric properties and microstructures of (1-x)SrTiO3-xSrZrO3 ceramic system were investigated (x=0.01,0.03,0.05,0.07). A single-phase structure was obtained for all compositions. The unit-cell volume of all compounds increased as x increased. For (1-x)SrTiO3-xSrZrO3 ceramic system, as x > 0.05mol, a phase transition from cubic to tetragonal was proved by using program DIVOL91. SrTiO3 ceramics with SrZrO3 addition can be sintered to 96% theoretical density. At frequency 50MHz, The dielectric constant value of (1-x)SrTiO3-xSrZrO3 ceramics increased from 315 to 355 with the SrZrO3 addition up to the 0.03 mol SrZrO3 fraction, and then decreased slightly. With the x value increased from 0.01 to 0.05, the dielectric loss value decreased from 6.5 × 10-3 to 1.2 ×10-3, and the BDS value increased from 11.4kv/mm to 14.4kv/mm. But when x =0.07, the dielectric loss value increased while the BDS value decreased slightly. These results could be explained by the effect of density, grain size, defect chemistry and large flaw on the dielectric properties of the specimens.Then Bi2O3 · TiO2 was added to the 0.95SrTiO3-0.05SrZrO3 system and different sintering process was produced. The effect of Bi2O3 · TiO2 content on the dielectric performances of (1-x)(0.95SrTiO3-0.05SrZrO3)-xBi2O3 · TiO2 system was studies. When mole fraction x=0.05, the excellent properties of the system had been obtained. Sintered in 1350℃ for 3h, 0.95(0.95SrTiO3- 0.05SrZrO3)-0.05Bi2O3 · TiO2 system exhibited extraordinary dielectric properties: εr.=510, tanδ =11 × 10-3, Eb =9.4kv/mm... |
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