Sealing Glass


MO-SCI has taken two distinct approaches to developing high-temperature sealant materials for solid oxide fuel cells (SOFCs) and other applications such as sodium-ion batteries. The first is the traditional glass-ceramic seal in which the glass crystallizes and bonds to seal components. The second approach bonds to metals and ceramics, but the alkali-free composition of the glass has been tailored to operate in a viscous state while resisting crystallization. Compliant or viscous glass seals are a new class of SOFC seal and are designed to be vitreous at the SOFC stack operating temperatures. Viscous seals have the potential to reduce the risk that thermal stresses will result in catastrophic seal failure through viscous healing of cracks if they form during thermal cycling.


Schematic showing where sealing glasses are used in SOFCs



Commercial Products: Below both the glass-ceramic and viscous type sealing glasses are listed with relevant material properties.


Commercially Available Glass-Ceramic Sealants and Target Properties

GL Number Ts (oC) Tg (oC) CTE (/oC)
1350 740 700 10×10-6
1702 688 665 7.6×10-6


Commercially Available Viscous Sealants and Target Properties

GL Number Ts (oC) Tg (oC)
1681* 640 624
1707* 589 553
1709* 639 604

*U.S. and International Patents Pending Sealing Glass Brochure

Note: This is an area of current research and development and additional compositions are in the commercialization process at this time. Please contact MO-SCI about the availability of other compositions if the options above will not suit your application.