Preparation of monoclinic celsian glass-ceramic by a solid-state reaction of the BaO–Al2O3–SiO2 eutectic glass, BaAl2O4 and SrAl2O4

A simple, rapid and efficient approach for the monoclinic celsian glass-ceramic fabrication is proposed here. The first step was preparing the amorphous BaO–Al2O3–SiO2 glass powder (BAS, with a eutectic temperature of 1400 °C). The second step was fabricating glass-ceramics by the solid-state reaction of the amorphous BAS glass, BaAl2O4 and SrAl2O4 powders. The formation mechanism of monolithic celsian is analyzed via differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The monolithic celsian rapidly formed at 1350 °C with 1.5 h due to the presence of SrAl2O4. And the complete monolithic celsian glass-ceramic is obtained as soon as the content of SrAl2O4 exceed 0.2 mol. The coefficient of thermal expansion (CTE) is determined from ambient temperature to 1200 °C, and the result indicates that with an increase in the SrAl2O4 content, the CTE of glass-ceramic decreases first and then increases. And the monolithic celsian glass-ceramic containing 0.2 mol SrAl2O4 has the lowest CTE of 4.927 × 10−6/oC (20–1200 °C). Besides, the prepared monolithic celsian glass-ceramic has an excellent phase stability at 1600 °C, which is higher than the temperature of the phase transition from monolithic into hexagonal occurring.