Effects of sintering time on crystal structure, dielectric properties and conductivity of (Ca_0.8Sr_0.2)ZrO₃ ceramics

(Ca_0.8Sr_0.2)ZrO₃ ceramics were prepared using solid-state reaction process, which were sintered at 1,480 C 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_0.8Sr_0.2)ZrO₃ 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) ų, Z = 4]. The (Ca_0.8Sr_0.2)ZrO₃ ceramics sintered at 1,480 C 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/ C. The Arrhenius plot of the dc electrical conductivity changed significantly with increasing sintering time.