Effects of sintering time on crystal structure, dielectric properties and conductivity of (Ca_(0.8)Sr_(0.2))ZrO_3 ceramics

摘要

(Ca_(0.8)Sr_(0.2))ZrO_3 ceramics were prepared using solid-state reaction process, which were sintered at 1,480 ℃ for different sintering time (2, 4, 6, 8, 10, 12 h, respectively), their structures were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. Rietveld refinement for the (Ca_(0.8)Sr_(0.2))ZrO_3 sintered for 10 h was carried out by powder XRD at room temperature and it crystallizes in orthorhombic space group Pnma [a ＝ 5.77341(4) Å, b ＝ 8.05569(6) Å, c ＝ 5.63318(4) Å and V ＝ 261.9920(30) Å~3, Z ＝ 4]. The (Ca_(0.8)Sr_(0.2)ZrO_3 ceramics sintered at 1,480 ℃ for 2-12 h possessed a dielectric constant (ε_r) of 23.6-27.9, a quality factor (Q × f) of 2,160-21,460 GHz and a temperature coefficient of resonant frequency (τ_f) from -14 to ＋13.6 ppm/ ℃. The Arrhenius plot of the dc electrical conductivity changed significantly with increasing sintering time.