Microstructures And Microwave Dielectric Properties Of Bi_2O_3-Deficient Bi_(12)Sio_(20) Ceramics

摘要

The Microstructure and microwave dielectric properties of Bi_2O_3-deficient Bi_(12)SiO_(20) ceramics were investigated. A small amount of unreacted Bi_2O_3 phase melted during sintering at 825℃ and assisted with densification and grain growth in all samples. The melted Bi_2O_3 reacted with remnant SiO_2 during cooling to form a Bi_4Si_3O_(12) secondary phase. The nominal composition of Bi_(11.8)SiO_(19.7)ceramics sintered at 825℃ for 4 h had a high relative density of 97% of the theoretical density, and good microwave dielectric properties: ε_r = 39, Q × f = 74 000 Ghz, and T_f= -14.1 ppm/℃. Moreover, this ceramic did not react with Ag at 825℃.