Synthesis and Microwave Dielectric Properties of MgSiO3 Ceramics

MgSiO3 ceramics were synthesized and their microwave dielectric properties were investigated. The Mg2SiO4 phase was formed at temperatures lower than 1200°C, while the orthorhombic MgSiO3 phase started to form by the reaction of SiO2 and Mg2SiO4 in the specimen fired at 1200°C. The structure of the MgSiO3 ceramics was transformed from orthorhombic to monoclinic when the sintering temperature exceeded 1400°C. A dense microstructure was developed for the specimens sintered at above 1350°C. The excellent microwave dielectric properties of ɛr=6.7, Q×f=121 200 GHz, and τf=−17 ppm/°C were obtained from the MgSiO3 ceramics sintered at 1380°C for 13 h.