METHOD OF MAKING FUEL CELL INTERCONNECT USING POWDER METALLURGY
Methods of fabricating an interconnect for a fuel cell stack include providing a powder in a die cavity of a powder press apparatus, where the powder includes at least one of a pre-alloyed powder and a pre-sintered powder, compressing the powder in the die cavity of the powder press apparatus using high velocity compaction to form a pressed powder interconnect, and incorporating the pressed powder interconnect into a fuel cell stack, wherein the pressed powder interconnect is incorporated into the fuel cell stack without first sintering the pressed powder interconnect.
1 . A method of fabricating an interconnect for a fuel cell stack, comprising:
providing a powder in a die cavity of a powder press apparatus, wherein the powder comprises at least one of a pre-alloyed powder and a pre-sintered powder;
compressing the powder in the die cavity of the powder press apparatus using high velocity compaction to form a pressed powder interconnect; and
incorporating the pressed powder interconnect into a fuel cell stack, wherein the pressed powder interconnect is incorporated into the fuel cell stack without first sintering the pressed powder interconnect.
2 . The method of claim 1 , wherein the pressed powder interconnect is incorporated in the fuel cell stack without first performing a controlled oxidation of the pressed-powder interconnect.
3 . The method of claim 1 , wherein the powder comprises a pre-alloyed powder comprising metal alloy particles each containing two or more metals.
4 . The method of claim 3 , wherein the pre-alloyed powder contains chromium and iron.
5 . The method of claim 4 , wherein the pre-alloyed powder is formed using at least one of a direct reduction technique using chrome ore (Fe x Cr y O z ), an aluminothermic process, and a silicothermic process.
6 . The method of claim 4 , wherein the powder comprises a mixture of a pre-alloyed powder containing chromium and iron and at least one of a pre-sintered chromium-iron powder, an elemental chromium powder and an elemental iron powder.
7 . The method of claim 4 , wherein the pre-alloyed powder comprises particles having at least one of a mean and a median dimensional size that is between about 110-160 μm.
8 . The method of claim 4 , wherein the pre-alloyed powder comprises pre-alloyed particles having at least one of a mean and a median dimensional size that is less than about 30 μm that are agglomerated to provide agglomerated particle clusters having at least one of a mean and a median dimensional size that is between about 110-160 μm.
9 . The method of claim 4 , wherein the powder is provided in the die cavity such that the average CTE of the compressed powder interconnect substantially matches a coefficient of thermal expansion (CTE) of a component of a fuel cell.
10 . The method of claim 9 , wherein the component of a fuel cell comprises a solid oxide electrolyte material of an electrolyte-supported solid oxide fuel cell.
11 . The method of claim 1 , wherein the powder is compressed without any organic lubricant being present in the powder.
12 . The method of claim 1 , wherein at least a portion of the metal powder comprises recycled interconnects that have been crushed.
13 . The method of claim 1 , wherein providing the powder in the die cavity of the powder press apparatus comprises providing a metal powder comprising at least one of a pre-alloyed powder and a pre-sintered powder and a coating material powder above or below the metal powder in a die cavity, and compressing the powder comprises compressing the metal powder and the coating material powder to form an interconnect having a coating of the coating material on at least one surface of the interconnect.
14 . The method of claim 13 , wherein the coating material comprises lanthanum strontium manganite (LSM).
15 . The method of claim 13 , wherein the coating material comprises a spinel.
16 . The method of claim 15 , wherein the coating material comprises a (Mn, Co) 3 O 4 spinel.