Theoretical calculations of the thermal expansion coefficient of glass-ceramic sealing materials in solid oxide electrolysis cell

Three series of glasses, BaO–CaO–SiO2–Al2O3, SrO–SiO2–Al2O3 and SrO–CaO–SiO2–Al2O3 were prepared. The coefficients of thermal expansion (CTE) of as-cast glasses were measured using dilatometer from room temperature to their glass transition. A new method — Average Field Strength Method was developed to accurately calculate the CTEs of all glasses and compared with traditional method (Appen method). Through comparison between calculated results and experimental results, the relation between the average field strength and the average field strength coefficient was found. With the increase of average field strength, the CTE of glasses calculated by the Average Field Strength Method of glass decreases smoothly. The CTEF were very close to the experimental results. The errors between them were smaller than 3%. The error between the CTE of glasses calculated by traditional method and the experimental CTE was near 40%. The average Field Strength Method can be used to accurately calculate the CTE, and estimate the change trends of CTE.