Method for bonding a porous metal layer to a cermet surface
AssigneeMesserschmitt-Boelkow-Blohm GmbH
InventorsHans Hofmann, Hartmut Wendt
Life of this patent
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Abstract
The bonding of a porous metal layer to at least one surface of a cermet is accomplished, without a supporting metal netting in the green cermet blank, by using a reducible metal oxide in the green cermet blank and a reducible metal oxide layer on the surface or surfaces of the green blank. In the following reducing sintering step the metal component in the green blank and the porous metal layer are formed simultaneously resulting in an intimate strong bond between the cermet blank and the porous metal layer. Both reducible metal oxides may be the same. The resulting product, such as an electrode-diaphragm-electrode structure is well suited for use in water electrolysis, chlorine alkaline electrolysis, and in fuel cells.
Claims21
A method for bonding a porous metal layer to a cermet surface of a cermet blank to form a cell or bi-polar plate in which the cermet acts as an electrically non-conducting diaphragm and the porous metal layer acts as an electrode, comprising the following steps:
- (a) preparing a ceramic component and a metal component for the formation of said cermet blank, said ceramic component being selected as a calcined, milled component from the group consisting of alkaline earth metal oxides, alkaline metal oxides, rare earth metal oxides, amphoteric oxides of Sub-Groups III, IV, V, and VI of the periodic table and any mixture of the just listed group, said metal component being selected in the form of a first reducible metal oxide powder from the group consisting of Sub-Groups I, II and VIII of the period table,
- (b) mixing said ceramic component and said first reducible metal oxide powder to form a cermet mixture, wherein said first reducible metal oxide powder is so proportioned that a resulting metal proportion in said cermet blank corresponds to about 5% by weight to about 40% by weight of said cermet blank,
- (c) preparing from said cermet mixture a green cermet blank without any supporting metal netting in said green cermet blank,
- (d) applying a coating of a second reducible metal oxide including an activating metal to at least one surface of said green cermet blank, and
- (e) subjecting said green cermet blank and said coating to a reducing sintering for forming from said first reducible metal oxide powder said metal component of said cermet blank having improved bonding capabilities, and for forming simultaneously from said second metal oxide said porous metal layer effectively bonded to said cermet surface thereby providing said cermet blank with said metal layer bonded thereon, said bonded cermet having high mechanical stability and sufficient flexibility to act as said diaphragm and electrode of said bi-polar plate.
Dependencies are inferred from the claim text.