SrO‐Containing Diopside Glass–Ceramic Sealants for Solid Oxide Fuel Cells: Mechanical Reliability and Thermal Shock Resistance

A series of glasses and glass–ceramics (GCs) aiming at applications as sealants for solid oxide fuel cells (SOFCs) were synthesized by partial substitution of Ca for Sr in the diopside‐Ba disilicate composition. X‐ray diffraction in conjunction with the Rietveld‐RIR technique were employed to quantify the crystalline (diopside and Sr‐diopside) and amorphous phases in the glasses sintered/heat treated at 850 °C in humidified 10%H₂–90%N₂ gas mixture for 250 h. Weibull modulus varied in the range 11.6–34.4 implying toward good mechanical reliability of synthesized GCs. Thermal shock resistance of model electrochemical cells made of yttria‐stabilized zirconia, gadolinia‐doped ceria, and lanthanum gallate based solid electrolytes, hermetically sealed by one diopside‐based composition, was evaluated employing quenching from 800 °C in air and water. Suitable thermal expansion coefficient, mechanical reliability, and strong adhesion to stabilized zirconia and metallic interconnects, are all suggesting a good suitability of the sealants for SOFC applications.