Sintering Mechanism and Microwave Dielectric Properties of Bi12 TiO20 Ceramics

A homogeneous Bi12TiO20 phase was developed in a specimen that was calcined at 700°C without the formation of a secondary phase. A small amount of the Bi12TiO20 phase melted during sintering and assisted the densification of the specimen. The Bi2O3 and Bi8TiO14 secondary phases were found in all specimens. All the specimens that were sintered at temperatures ≥775°C exhibited high relative densities above 98% of the theoretical density. The Q × f value of the Bi12TiO20 ceramics was influenced by the grain size. The Bi12TiO20 ceramics sintered at 800°C for 5 h showed promising microwave dielectric properties of er = 41, Q × f = 10 400 GHz, and τf = −10.8 ppm/°C.