Synthesis and dielectric properties of Ba2TiSi2O8 glass-ceramics from the sol-gel process

The Ba2TiSi2OR glass-ceramics were prepared by sol-gel process using barium acetate, titanium butoxide, tetraethoxyorthosilicate and boric acid as raw materials. Because of the existence of glass and sintering additive, the Ba2TiSi2O8 glass-ceramics can be sintered at 880 degrees C in air. The structure of sintered sample was characterized by means of XRD and SEM. XRD patterns showed that fresnoite Ba2TiSi2O8 is the dominant crystalline phase in the sintered samples. SEM images indicated that the shape of Ba2TiSi2O8 grains varied with the molar ratio of ([Ba(Ac)(2)/Ti(OBun)(4)/Si(OEt)(4)]). With an increase of Si(OEt)(4) content, the length/diameter ratio of Ba2TiSi2O8 grains decreases. The Ba2TiSi2O8 glass-ceramics studied in this work have epsilon(r) in the range of 6-12 (100 MHz) and demonstrate very low dielectric losses (tan delta <2 X 10(-3), 100 MHz). The experimental results suggested that the Ba2TiSi208 glass-ceramics could be used as dielectric materials for low temperature co-fired ceramics (LTCC) process.