Reactive Air Brazing: Method of Joining Ceramic and Metal Parts in Solid Oxide Fuel Cells
Researchers at PNNL have developed a new, low-cost method for hermetically sealing ceramic and metallic components used in high-temperature electrochemical devices.Description
The technique, referred to as reactive air brazing (RAB), utilizes a novel copper oxide-silver single phase liquid as the basis for joining electrochemically active ceramics such as yttria stabilized zirconia and lanthanum strontium cobalt ferrite to oxidation resistant materials such as FeCrA1Y. Materials of this type care commonly employed in the oxygen generators used in syngas production, solid oxide fuel cells and solid-state sensors.
Unlike the previous sealing techniques, based primarily on high-temperature glasses, the RAB joints exhibit excellent thermal cycling performance and long-term stability in both high-temperature oxidizing and reducing atmospheres. An additional advantage of the RAB technique is that the sealing process is conducted in-air, which minimizes the capital expenses and operating costs associated with the joining operation.
This innovative method enables cost-reduction and performance in wide-array of potential applications.
- Useful for ceramic-metal and ceramic-ceramic joining
- Joining is completed directly "in air"
- Results in high-strength, ductile joint
- Chemical sensors
- Solid oxide fuel cells
- Gas separation devices
|Title and Abstract||
Oxidation ceramic to metal braze seals for applications in high temperature electrochemical devices and method of making
A method of joining metal and ceramic parts, wherein an alumina forming metal part and a ceramic part are provided. A braze material in placed between the alumina forming metal part and the ceramic part, and the combination is then heated in an oxidizing atmosphere, preferably in air at a temperature of between 500.degree. C. and 1300.degree. C. The alumina forming metal parts are selected from the group consisting of high temperature stainless steels, such as Durafoil (alpha-4), Fecralloy, Alumina-coated 430 stainless steel and Crofer-22APU, and high temperature superalloys such as Haynes 214, Nicrofer 6025, and Ducraloy. The braze material is selected as a metal oxide-noble metal mixture, preferably Ag--CuO, Ag--V.sub.2O.sub.5, and Pt--Nb.sub.2O.sub.5, and more preferably between 30.65 to 100 mole % Ag in CuO.
|Pacific Northwest National Laboratory||06/06/2006
|Technology ID||Development Stage||Availability||Published||Last Updated|
|14310||Prototype - Reduced to practice||Available - Available for licensing in all fields||09/10/2010||09/10/2010|