Effect of Li₂CO₃ on the microwave dielectric properties of 0.94Mg₂SiO₄-0.06Ca_0.9Sr_0.1TiO₃ ceramics

The effects of Li₂CO₃ on sintering and microwave dielectric properties of 0.94Mg₂SiO₄-0.06Ca_0.9Sr_0.1TiO₃ ceramics synthesized by a traditional solid-state reaction method were investigated. The results show that the addition of Li₂CO₃ did not change the phase of ceramics. Appropriate Li₂CO₃ addition could accelerate the sintering process, which could lower the sintering temperature from 1440℃ to 1355℃. Moreover, the addition of Li₂CO₃ improve the microwave dielectric properties and the Q×f increases apparently. The decrease in density and deterioration of Q×f were observed in the samples with excessive Li₂CO₃. The optimal microwave dielectric properties: ε_r=7.96, Q×f=96409 GHz (f=14.571 GHz), τ_f=+4.62 ppm/℃ were obtained for 0.94Mg₂SiO₄-0.06Ca_0.9Sr_0.1TiO₃ doped with 0.50wt% Li₂CO₃ sintered at 1355℃ for 3 h.