Influence of CCTO Doped Amount on Property of BST Capacitor Ceramics Sintered at Low Temperature

Abstract

(1-x) Ba_0.65Sr_0.35TiO₃-xCaCu₃Ti₄O₁₂(BST-CCTO) ceramics was prepared by traditional solid-state reaction method, the effect of CaCu₃Ti₄O₁₂ (CCTO) doped on microstructure and phase composition and dielectric properties of BST ceramics were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM) and other analytical methods. The results show that the microstructure and the dielectric properties and the optimum sintered temperature of BST ceramic materials would be greatly affected by the CCTO doped amount. Appropriate doping amount can be fully incorporated into the perovskite lattice of BST and had the excellent performance. While excessive CCTO doping could lead to the appearance of second phase, and the second phase was coexisted with BST in the ceramics. BST ceramics had the optimum properties, ϵ_r of 1992, tan δ of 0.006, E_b of 5.5 kVmm⁻¹ (Alternating Current, AC) and the value of ΔC/C ranges was 13.6% and −14.1% in −55°C∼+125°C temperature range and its capacitance temperature property was suited for X7R, the curie temperature was 15°C and the optimum sintered temperature was 1260°C when CCTO doped amount was 1 wt.%.

Keywords:

• BST ceramics
• capacitor ceramics
• dielectric properties
• CCTO doping