A method for improving temperature stability of dielectric permittivity for BaTiO3 ceramics

Barium titanate ceramic is generally employed as capacitor material owing to its large dielectric permittivity, and has been widely used in electronic and energy storage devices. However, the dielectric permittivity varies sharply in the vicinity of Curie temperature, which restricts thermal stability for its relevant devices. Therefore, it is of practical importance to improve the dielectric temperature stability for its application reliability. In this paper, we report an approach to enhance the temperature stability of dielectric permittivity through introducing the composition gradient in barium titanate ceramic. Firstly, the graded ceramic (consisting of BaTiO
3
-xBaSnO
3
, x=0.07, 0.09, 0.105, 0.12, 0.14) was prepared by a conventional solid state reaction process with a modified forming process. Secondly, a comparison has been made between the temperature dependency of dielectric property with different composition gradient arrangement by simulation, and the optimal one has been selected. Finally, the dielectric permittivity of graded ceramic was measured and it has been found that the temperature variation parameter Δ∊
r
% = (∊
r
— ∊
r25°C
)/∊
r25°C
of graded ceramic is lower than that of other single composition ceramic from 20°C to 60°C, which verifies the validity for composition gradient method to improve the dielectric temperature stability of BaTiO
3
ceramics.