Effects of Bi4Ti3O12 on Microstructure and Dielectric Properties of BaTiO3 Ceramics

• Main Authors: Chih-cheng Chen, 陳致丞
• Other Authors: Kuan-zong Fung
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/86660306603377669404

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 95 === BaTiO3 is widely used in multilayer ceramic capacitors because of its high permittivity. In order to increase the stability of BaTiO3, to suppress the variation of permittivity and to increase the Curie temperature (TC) are important. In the case, the effects of Bi4Ti3O12 (BIT) on microstructure and dielectric properties of BaTiO3 ceramics have been studied, and the effects of Mn on TC and dielectric properties of Bi4Ti3O12 doped BaTiO3 have been discussed. From the results, there is a second phase (Bi2Ti2O7) observed in Ba(Ti0.99Mn0.01)O3 ceramics that were sintered under air with increasing the BIT content. But there is no second phase observed in Ba(Ti0.99Mn0.01)O3 ceramics as sintered under reduced atmosphere. The 2mol% BIT doped Ba(Ti0.99Mn0.01)O3 that were sintered under air has the highest TC and the variation of permittivity decreases with increasing the BIT content; The dielectric properties of Ba(Ti0.99Mn0.01)O3 ceramics that were sintered under reduced atmosphere are better than that were sintered under air, and the variation of Ba(Ti0.99Mn0.01)O3 ceramics is less than 20% from -55℃ to 150℃ when 2mol% BIT was added. To compare with the Ba(Ti0.99Mn0.01)O3 system, the TC of Mn un-doped BaTiO3 decreased with increasing BIT content reversely. It could be suggested that the low diffusivity of Mn suppresses the diffusion of BIT into BaTiO3 grains and the core-shell structure has been formed. So the TC and dielectric stability of Ba(Ti0.99Mn0.01)O3 ceramics have been increased. However, after increasing the sintering time or the amount of BIT, core-shell structure collapses, and the TC and dielectric stability of Ba(Ti0.99Mn0.01)O3 ceramics have been decreased.