Battelle Memorial Institute

Delphi Technologies, Inc.

John S Hardy

Jin Yong Kim

Kenneth Scott Weil

Jung-Pyung Choi

K Scott Weil

Karl Jacob Haltiner, Jr

Subhasish Mukerjee

Joseph M Keller

Gary F Reisdorf

Larry R Pederson

Olga A Marina

Edwin C Thomsen

Peter C Rieke

Gregory W Coffey

Prabhaker Singh

A method for joining two ceramic parts, or a ceramic part and a metal part, and the joint formed thereby. The method provides two or more parts, a braze consisting of a mixture of copper oxide and silver, a diffusion barrier, and then heats the braze for a time and at a temperature sufficient to form the braze into a bond holding the two or more parts together. The diffusion barrier is an oxidizable metal that forms either a homogeneous component of the braze, a heterogeneous component of the braze, a separate layer bordering the braze, or combinations thereof. The oxidizable metal is selected from the group Al, Mg, Cr, Si, Ni, Co, Mn, Ti, Zr, Hf, Pt, Pd, Au, lanthanides, and combinations thereof.

Diffusion barriers in modified air brazes

A joint for use in electrochemical devices, such as solid oxide fuel cells (SOFCs), oxygen separators, and hydrogen separators, that will maintain a hermetic seal at operating temperatures of greater than 600&#xb0; C., despite repeated thermal cycling excess of 600&#xb0; C. in a hostile operating environment where one side of the joint is continuously exposed to an oxidizing atmosphere and the other side is continuously exposed to a wet reducing gas. The joint is formed of a metal part, a ceramic part, and a flexible gasket. The flexible gasket is metal, but is thinner and more flexible than the metal part. As the joint is heated and cooled, the flexible gasket is configured to flex in response to changes in the relative size of the metal part and the ceramic part brought about by differences in the coefficient of thermal expansion of the metal part and the ceramic part, such that substantially all of the tension created by the differences in the expansion and contraction of the ceramic and metal parts is absorbed and dissipated by flexing the flexible gasket.

Joint with application in electrochemical devices

The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells. Also provided are electrochemical devices that include active oxygen reduction electrodes, such as solid oxide fuel cells, sensors, pumps and the like. The compositions comprises a copper-substituted ferrite perovskite material. The invention also provides novel methods for making and using the electrode compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having cathodes comprising the compositions.

Copper-substituted perovskite compositions for solid oxide fuel cell cathodes and oxygen reduction electrodes in other electrochemical devices

In assembling an SOFC fuel cell stack from a plurality of cassettes, the mounting plate of one cassette is attached to, and insulated from, the separator plate of the next-adjacent cassette by a peripheral dielectric seal consisting of a ceramic coating and a metal braze. Materials suitable for the ceramic coating include yttrium stabilized zirconia (YSZ), zirconia toughened alumina, magnesium silicates such as the mineral forsterite, magnesium aluminates, magnesium aluminosilicates and lanthanum zirconate. The ceramic coating may be applied to the cassette's outer surface in known fashion as by physical vapor deposition, chemical vapor deposition, sputtering, and various methods of plasma spray. An underlayer of alumina may also be used to provide a redundant layer of electrical insulation.

Ceramic coatings for insulating modular fuel cell cassettes in a solid-oxide fuel cell stack

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&#xb0; C. and 1300&#xb0; 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&#x2014;CuO, Ag&#x2014;VO, and Pt&#x2014;NbO, and more preferably between 30.65 to 100 mole % Ag in CuO.

Oxidation ceramic to metal braze seals for applications in high temperature electrochemical devices and method of making

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Richland, WA, United States of America

John S Hardy