High-temperature Dielectrics In Theternary System

摘要

Perovskite solid solution in the (1-x)[0.4BiScO_3-0.6Ba TiO_3]+x (K_(1/2)Bi_(1/2))TiO_3 [BSBT-KBTx) system was synthesized using conventional sintering and hot-isostatic pressing. Dielectric properties of BSBT ceramics with different dopant levels of KBT were characterized as a function of temperature and frequency for potential use of high-temperature capacitors. The BSBT ceramics with KBT exhibited high dielectric permittivities (ε_r) (> 1700 at RT) and low dielectric loss over the temperature range from 100° to 300℃, with flat temperature coefficients of permittivity (TCεs). In addition, BSBT ceramics with increasing KBT were observed to possess dielectric relaxation characteristics at temperatures (>RT) as observed in lead-based relaxors. Furthermore, high energy densities, being on the order of 4.0 J/cm~3 at 220 kV/cm was observed for the BSBT-KBT20 ceramics from the electric-field polarization behavior.