Glass-Ceramic Seal

Pacific Northwest National Laboratory

One of the critical issues in designing and fabricating a solid oxide fuel cell (SOFC) stack is the development of appropriate materials and techniques for hermetically sealing the metal and/or ceramic components. Researchers at PNNL have developed a unique method that results in a stronger, more robust seal that can stand the tests of time.

This patented glass technology possess high resistivity and holds up well in both reducing and oxidizing environments. Additionally, this technology can be tailored to yield a wide range of thermal expansions. Sealing temperature may also be adjusted over a range of 750-950° C. The seal material has exhibited very strong bonding to both zirconia and ceria-based ceramic with little or no interaction after thousands of hours of operation at elevated temperature. Due to the high amount of crystalline material in the seal, it is resistant to creep, which is necessary for long-term operation at temperature. One composition has operated in a SOFC stack in excess of 4,000 hours.

The seal is a blend of MAO-MBOy-SiO2 that substantially matches a coefficient of thermal expansion of the solid electrolyte. A series of glass ceramics in the MAO-MBOy-SiO2 system can be used to join or seal both tubular and planar ceramic solid oxide fuel cells, oxygen generators, electrolyzers, and membrane reactors for the production of syngas, commodity chemicals and other products.


  • Thermal expansion and sealing temperature can be tailored to specific need
  • Better structural properties (creates a rigid material without viscous flow)
  • Resulting material is more robust, providing for a stronger seal
  • In manufacture, the method does not require a high compressive load to form a strong seal. This removes load considerations for other components, which must be able to stand up to the load in a load-bearing sealing process.

Applications and Industries

Potential Industry Applications:

  • Aerospace & Defense
  • Agriculture & Mining
  • Automotive & Transportation
  • Computers & Electronics
  • Consumer Products
  • Energy & Utilities
  • Manufacturing & Warehousing

Patent Information

Number Issued On Title
6,430,966 08/13/2002 Glass-ceramic material and method of making
6,532,769 03/18/2003 Glass-ceramic joint and method of joining

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