Microwave dielectric properties of bismuth layer-structured Ca2−xSrxBi4Ti5O18 (0 ≤ x ≤ 0.6) ceramics

Abstract

Ceramics of five-layered Ca 2 Bi 4 Ti 5 O 18 (CBT) exhibit relatively high dielectric constants at high frequency. In this study, Sr 2? ions were added to substitute Ca 2? ions so as to improve the microwave dielectric properties of CBT ceramics. Densification, microstructural evolution, and microwave dielectric properties of Ca 2-x Sr x Bi 4 Ti 5 O 18 (CSBT), with x ranging from 0.0 to 0.6, were investigated. Besides, relation of sintering temperature and microscopic structure was also investigated. With increasing levels of Sr 2? ions additions, the relative permittivity increases from 170 to 202 but Q 9 f decreases from 868 to 428 GHz. Typically, dielectric properties of e r = 180 and Q 9 f = 759 GHz were obtained for the Ca 1.8 Sr 0.2 Bi 4 Ti 5 O 18 specimens sintered at 1,175°C for 5 h.