Silver cofirable (Ca0.9, Mg0.1)SiO3 microwave dielectric ceramics with Li2CO3–Bi2O3 additive

The effects of Li2CO3–Bi2O3 (LB) additive on the microstructure, phase formation, microwave dielectric properties and applicability for low-temperature co-fired ceramics (LTCC) technology of (Ca0.9Mg0.1)SiO3 (CMS) ceramics were investigated. The sintering temperature of the CMS ceramics was reduced from 1290 °C to 890 °C by the addition of LB. Secondary phases SiO2 and Bi4(SiO4)3 were detected when LB content was less than 9 wt%. Low melting point liquid phases were formed when LB content was 11–14 wt%. The Qf value initially increased with the addition of LB and attained the maximum value for the 9 wt% LB-doped CMS ceramic. When the LB content exceeded 9 wt%, the Qf value decreased because of the presence of liquid phase and abnormal growth of grains. ɛr of 6.92, Qf of 27,600 GHz and τf of −43.6 ppm/°C were obtained for 9 wt% LB-doped CMS ceramics sintered at 890 °C for 2 h. Also the ceramics can be well co-fired with Ag electrode.