Abstract

The present invention relates to a powder metallurgical moulding forming an interconnector (2) or an end plate for an electrochemical cell, which moulding has a chromium content of at least 80% by weight, a plate-like basic shape and (a) flow ffeld(s) (6) with structuring(s) (5) formed on one or both of the main faces (4) of the moulding. A ratio of the maximum diameter Dmax of the Moulding, measured along the main face (4), to a minimum thickness drain of a core region of the moulding which extends along the flow field/fields (6) and is not affected by the structuring(s) (5) is in the range 140 Dmax/dmin 350.

IPC Classes  ?

• H01M 8/02 - Fuel cells; Manufacture thereof - Details

Abstract

The invention describes a powder or powder granulate having a chromium content > 80 Mass%, which contains 2 to 20 Mass% iron, optionally up to 5 Mass% dopant, and optionally up to 2 Mass% oxygen, wherein the chromium-containing particles at least partially have pores. The powder according to the invention displays significantly improved compression behaviour and allows the production of sintered components having a very homogeneous distribution of the alloy elements.

IPC Classes  ?

• B22F 9/20 - Making metallic powder or suspensions thereof; Apparatus or devices specially adapted therefor using chemical processes with reduction of metal compounds starting from solid metal compounds
• B22F 9/22 - Making metallic powder or suspensions thereof; Apparatus or devices specially adapted therefor using chemical processes with reduction of metal compounds starting from solid metal compounds using gaseous reductors
• C22C 27/06 - Alloys based on chromium

Abstract

The invention relates to a metal powder having a chromium content of at least 90 Ma%, characterized by having a nano hardness according to EN ISO 14577-1 of = 4 GPa and/or by a green strength measured according to ASTM B312-09 of at least 7 MPa at a compression pressure of 550 MPa.

IPC Classes  ?

• B22F 9/22 - Making metallic powder or suspensions thereof; Apparatus or devices specially adapted therefor using chemical processes with reduction of metal compounds starting from solid metal compounds using gaseous reductors

Abstract

A powder metallurgical molded part includes a disk or plate-like main body and a row of knob-shaped and/or ridge-shaped elevations in a row direction having a height perpendicular to a main plane of the main body and a cross section with side flanks leading from an outer end contour in height direction of the elevation via rounded corner portions into curved portions with a curve radius. The curve radius merges into the surface contour of the main body and a rectilinear flank portion or tangent of the side flank lying at the point where the rounded corner portion merges into the curved portion is disposed at an angle of inclination to the main plane. At least two different angles of inclination are on the same side of the main body and the at least two different angles of inclination represent at least first and second geometries.

IPC Classes  ?

• B22F 3/02 - Compacting only
• B22F 3/12 - Both compacting and sintering
• B22F 5/00 - Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
• B22F 5/06 - Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of threaded articles, e.g. nuts
• B22F 5/08 - Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of cam discs

Abstract

The invention relates to a layer structure which is formed between an interconnect and a cathode of a solid oxide fuel cell and can be used for forming a ceramic layer structure between an interconnect and a cathode. In this respect, the interconnect comprises a metal alloy containing chromium. The object of the present invention is to provide a layer structure between an interconnect and a cathode of a solid oxide fuel cell with which a good protective function (from corrosion and from chromium vaporization), a high electrical conductivity and also a good thermal expansion behavior adapted to the materials of an interconnect and of a cathode can be achieved. The layer structure in the green state is formed by a powdery spinel as well as at least one of the below-named metal oxides CuO, NiO, CoO x and MnO x as a sintering additive and at least one powdery perovskite. In this respect, chromium is not contained in any of these chemical compounds and the portion of spinel contained with the metal oxides as a sintering additive is reduced starting from the side facing the interconnect up to the side facing the cathode and the portion of perovskite is reduced starting from the side facing the cathode in the direction of the side facing the interconnect.

IPC Classes  ?

• H01M 8/0217 - Complex oxides, optionally doped, of the type AMO3, A being an alkaline earth metal or rare earth metal and M being a metal, e.g. perovskites
• H01M 8/0247 - Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the form
• C01G 45/00 - Compounds of manganese
• C01G 53/00 - Compounds of nickel

Abstract

The invention describes a shaped part, in particular an interconnector or an end plate for a fuel cell stack, which is produced by pressing and sintering a pulverulent starting material. The shaped part consists of a disc-shaped or plate-shaped basic body -1- having a multiplicity of knob-like and/or ridge-like elevations -2- with a height h. In cross section, each elevation -2- has two inclined side flanks which lead, proceeding from an end contour -3- of the elevation -2-, via rounded corner portions -4-, -4'- with a radius r or r' directly or via intermediate rectilinear portions -5-, -5'- into curved portions -6-, -6'- with a radius R or R', which in turn merge into the surface contour -7-, -7'- of the basic body -1-. The rectilinear portions -5-, -5'- or, in the case of a direct transition of the rounded corner portions -4-, -4'- into the curved portions -6-, -6'-, the tangents at the point of the transition, have an angle of inclination a or a' with respect to the surface contour -7-, -7'- in the range of 95° to 135°. According to the invention, the radius R or R' is in the range of 0.15 to 1 mm and the height h is dimensioned such that the ratio R: h or R' : h is in a range of 0.25 to 1.

IPC Classes  ?

• B22F 3/12 - Both compacting and sintering
• B22F 5/00 - Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
• H01M 4/70 - Carriers or collectors characterised by shape or form

Abstract

The invention describes an interconnector for a high-temperature solid electrolyte fuel cell composed of a sintered chromium alloy which has sintering pores and contains > 90% by weight of Cr, from 3 to 8% by weight of Fe and optionally from 0.001 to 2% by weight of at least one element of the group of rare earth metals; where the chromium alloy contains from 0.1 to 2% by weight of Al and the sintering pores are at least partially filled with an oxidic compound containing Al and Cr. The interconnector has a high impermeability to gas and dimensional stability.