Low-temperature sintering and microwave dielectric properties of CaMg1-xLi2xSi2O6(x=0-0.3) ceramics

In this study, low-temperature fired CaMg(1-x)Li(2x)Si(2)O(6)microwave dielectric ceramics were prepared via the traditional solid-state reaction method. In this process, 0.4 wt% Li2CO3-B2O3-SiO2-CaCO3-Al2O3(LBSCA) glass was added as a sintering aid. The results showed that ceramics consisted of CaMgSi(2)O(6)as the main phase. The second phases were CaSiO(3)always existing and Li(2)SiO(3)occurring at substitution contentx> 0.05. Li(+)substitution effectively lowered sintering temperature due to 0.4 wt% LBSCA and contributed to grain densification, and the most homogeneous morphology could be observed atx= 0.05. The effects of relative density, the second phase, and ionic polarizability on dielectric constant (epsilon(r)) were investigated. The quality factor (Qxf) varied with packing fraction that concerned the second phase. Moreover, the temperature coefficient of the resonant frequency (tau(f)) was influenced by MgO(6)octahedral distortion and bond valence. Excellent dielectric properties of the CaMg(1-x)Li(2x)Si(2)O(6)ceramic was exhibited atx= 0.05 with epsilon(r)= 7.44,Qxf= 41,017 GHz (f= 15.1638 GHz), and tau(f)= -59.3 ppm/degrees C when sintered at 900 degrees C. It had a good application prospect in the field of low-temperature co-fired ceramic (LTCC) substrate and devices.