The microwave dielectric properties of CaxBi4−xTi3O12−x/2 (0.0 ≤ x ≤ 1.4) ceramics

In this work CaxBi4−xTi3O12−x/2 ceramics were prepared by the conventional solid-state ceramic route. Densification, microstructural evolution and microwave dielectric properties of CaxBi4−xTi3O12−x/2 (x = 0.0, 0.6, 1.0, 1.2 and 1.4) were investigated. The room temperature structural data were obtained from X-ray diffraction (XRD). For x = 1.4, little secondary phases was observed. Therefore, the solubility limit of CaxBi4−xTi3O12−x/2 ceramics was estimated to x = 1.2. The microstructure and microwave dielectric properties were investigated as a function of the x-value and sintering temperature. Increasing sintering temperature can effectively promote the densification and dielectric properties of CaxBi4−xTi3O12−x/2 ceramics. With the content of Ca2+ ions increasing, the dielectric constant er and Q × f values increased at the beginning and then decreased. The optimal microwave dielectric property of er = 166, Q × f = 704 GHz was obtained for the Ca1.2Bi2.8Ti3O11.4 ceramic sintered at 1050 °C for 5 h. The relatively low sintering temperature and high dielectric properties in microwave range would make CaxBi4−xTi3O12−x/2 ceramics promising for application in electronics.