Solid-state synthesis of ceramics in the BaO–SrO–Al2O3–SiO2 system

The solid-state reaction route was successfully used to prepare (Ba,Sr)O–Al2O3–2SiO2 ceramics. Firstly, the mixed powder was characterized by differential thermal analysis and thermogravimetric analysis. The ceramics powder was obtained by calcining a BaCO3, SrCO3, Al2O3, and SiO2 mixture at 950 °C for 4 h. Secondly, the calcined powder was pressed, sintered at 1040 °C for 4 h, Then the sintered samples were investigated by X-ray diffraction, scanning electron microscopy, density measurement, and thermal mechanical analyzer. In this work, the appropriate addition of SrO was observed to enhance the hexacelsian to celsian transformation. Additionally, the appropriate addition of SrO effectively reduced the thermal expansion coefficient of the (Ba,Sr)O–Al2O3–2SiO2 ceramics.