Microstructure and dielectric properties of Bi(Li0.5Ta0.5)O3-modified Ba0.6Sr0.4Ti0.7Zr0.3O3-based ceramics
A series of lead-free perovskite-structured dielectric ceramics of (1-x)Ba 0.6 Sr 0.4 Ti 0.7 Zr 0.3 O 3 -xBi(Li 0.5 Ta 0.5 )O 3 ((1-x)BSTZ-xBLT, x = 0, 0.10, 0.15, and 0.20) were prepared through solid-state reaction method combined with conventional sintering. Specifically, for x = 0, 0.10, 0.15, and 0.20, the samples of (1-x)BSTZ-xBLT were sintered in air for 8 h at 1500 °C, 1300 °C, 1200 °C, and 1150 °C, respectively. All samples possess a pure perovskite structure and achieve a high relative density of 93 ~ 95%. The average grain size of all samples falls within 1.74 ~ 2.67 μm, and all composition elements distribute uniformly. The addition of BLT is conducive to reduce the sintering temperature of BSTZ. The critical electric field corresponding to the saturation polarization intensity of BSTZ increases from 69.4 kV/cm to 88.9 kV/cm as x rises from 0 to 0.10. The dielectric permittivity of 0.85BSTZ-0.15BLT and 0.80BSTZ-0.20BLT keeps stable (∆ \(\varepsilon\) / \(\varepsilon\) 25 °C ≤ ± 15%) in the test temperature of − 100 ~ 350 °C. The activation energy ( \(E\) α ) of BSTZ enhances from 0.86 eV to 1.72 eV as x rises from 0 to 0.20, which contributes to the broadening of the band gap. These results suggest that (1-x)BSTZ-xBLT ceramics are promising candidates for high-temperature ceramic capacitors.
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