Microstructure and dielectric properties with a contents Ca of (Sr.Ca)$TiO_3$-based grain boundary layer ceramics

(Sr.Ca)$TiO_3$계 입계층 세라믹의 Ca변화량에 따른 미세구조 및 유전특성

  • Published : 1994.11.01

Abstract

Microstructures and dielectric properties of (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$+0.006Nb$_{2}$O$_{5}$ (0.05.leq.x.leq.0.2) ceramic were investigated. The specimens fired in a reducing atmosphere(N$_{2}$) were painted on the surface with CuO paste, and then annealed at 1100.deg. C for 2 hr. SEM and EDAX revealed that CuO penetrated rapidly into the bulk along the grain boundaries during the annealing. Grain size increased with increasing Ca content up to 15[mol%], but decreased with further addition. In the specimens with 10-15[mol%l of Ca, excellent dielectric properties were obtained as follows; dielectric constant <25000, dielectric loss(tan .delta[%]) <0.3[%] and capacitance change rate with temperature <.+-.[%], respectively. All the specimens in this study exhibited dielectric relaxation with frequency as a function of the temperature. The dispersive frequency was over 10$^{6}$ [Hz].z].

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