Synthesis and Microwave Dielectric Properties of Sm2SiO5 Ceramics

The Sm 2 SiO 5 ceramics were synthesized and their microwave dielectric properties were investigated. The pure monoclinic Sm 2 SiO 5 phase could be obtained when the molar ratio of Sm 2 O 3 /SiO 2 was 1:1.05 at 1350°C. A small amount of hexagonal Sm 4 (SiO 4 ) 3 second phase occurred as temperature increased. The relative density of Sm 2 SiO 5 ceramics increased with increasing temperature. The Sm 2 SiO 5 ceramics sintered at 1500°C exhibited microwave dielectric properties: a dielectric constant (ε r ) of 8.44, a quality factor ( Q × f ) of 64 000 GHz, and a temperature coefficient of resonant frequency (τ f ) of −37 ppm/°C. The Sm 2 SiO 5 ceramics have a wide sintering temperature region and small negative τ f values. They are promising candidate materials for millimeter-wave devices.