Phase formation and properties of the BaO-B2O3-SiO2 and -Al2O3 ceramics prepared via an aqueous suspension route

► Barium silicates and hexacelsian ceramics are prepared at the sintering temperature of 850-940 oC. ► The BaO-B2O3 compositions can availably decrease the sintering temperature the barium silicate and hexacelsian ceramics. ► The presence of barium silicates and SiO2 crystal in the ceramics can urge a higher CTE (11-17 ppm oC−1). ► The formation of a hexacelsian phase can achieve a low permittivity and loss (permittivity: 7.1-7.4; loss: 5-7 × 10−4).