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

Abstract

The Ba₂TiSi₂O₈ 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 °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 ɛ_r in the range of 6–12 (100 MHz) and demonstrate very low dielectric losses (tanδ <2 × 10⁻³, 100 MHz). The experimental results suggested that the Ba₂TiSi₂O₈ glass-ceramics could be used as dielectric materials for low temperature co-fired ceramics (LTCC) process.