Low temperature sintering and dielectric properties of Ba0.6Sr0.4TiO3-MgO composite ceramics with CaO-B2O3-SiO2 glass addition

► CaO-B2O3-SiO2 glass was employed as the sintering aids. ► The sintering temperature of the composite ceramics was reduced to 850 °C effectively. ► Small dielectric loss of 2.0 × 10−3 was obtained. ► Relationships between glass additives and microstructure evolution were investigated. ► Relationships between glass additives and dielectric properties were discussed.