Effect of Li2CO3 on the properties of 0.7CaTiO3-0.3SmAlO3 ceramics

The effects of Li2CO3 additive on the properties of microwave dielectric material based on CSTA ceramic by conventional solid-state route were investigated. The results show that moderate addition of Li2CO3 effectively decreased the sintering temperature which droped from 1500°C to 1380°C. The XRD results suggest that addition of Li2CO3 doesn't change the crystal phase of ceramics. SEM analysis results show that Li2CO3 will inhibit grain growth. When the CSTA ceramics add 0.1wt% Li2CO3, grain size is small, evenly distributed. With the increasing of Li2CO3 additives, the glass phase increases, and some grains grow and unevenly distribute, which decreases the Q·f values. The CSTA ceramics doped with 0.1wt% Li2CO3 and sintered at 1380°C have the optimal microwave dielectric properties: Εr=45.09, Q·f=61600 GHz (f=6.417 GHz), τf=+7.54×10-6/°C.