Braze for Robust Seals with Ceramic

APPLICATIONS:

High temperature seals for electrochemical devices, oxygen generators, and metal/ ceramic interfaces

ADVANTAGES:

Enables rapid thermal cycling Overcomes brazing limitations without cost increases ABSTRACT:

Berkeley Lab scientists have developed a composite braze material that can be used to manufacture strong, gas-tight joints where one of the joining members is ceramic – typically yttrium stabilized zirconium (YSZ). The braze composition can be controlled to reduce the stress due to mismatched thermal expansion between the ceramic and the braze. Joints made using the new braze were failure-free after rapid thermal cycling up to 700°C.

Ceramics typically have a thermal expansion coefficient lower than most braze metals or alloys, which can result in weakening or cracking in the braze or ceramic. Berkeley Lab scientists add particles with low or negative expansion coefficients to the braze to attain sufficient matching to prevent this. A component that reacts with the ceramic surface can also be added, eliminating the need to metallize the ceramic prior to brazing.

Ceramic adhesives, glass, brazes, and mica have all been used as sealants in electrochemical devices, but all have limitations that prevent commercialization. This invention eliminates these barriers without increasing costs.

Type of Offer: Licensing



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