Iron coated chromium powder and SOFC IC made therefrom
A component, such as a SOFC interconnect, and methods of making the component are provided using various chromium powders, including powder particles with a chromium core covered with an iron shell, a pre-alloyed Cr—Fe powder or a chromium powder produced by hydrogen reduction with hydrogen.
1. A method of manufacturing an interconnect, comprising:
providing a pre-alloyed Cr—Fe powder; and
compacting the pre-alloyed Cr—Fe powder in a die to form the interconnect,
wherein the pre-alloyed Cr—Fe powder is made with a chromium or a chromium-iron melt made by an aluminothermic process, and wherein the chromium or the chromium-iron melt is purified to form a purified chromium or chromium-iron melt.
2. The method of claim 1 , wherein the aluminothermic process uses a chromium oxide as a starting material.
3. The method of claim 1 , wherein the aluminothermic process uses a chromium iron oxide or a mixture comprising a chromium oxide and an iron oxide.
4. The method of claim 1 , wherein the pre-alloyed Cr—Fe powder comprises 1-10 weight % iron.
5. The method of claim 4 , wherein the pre-alloyed Cr—Fe powder comprises 4-6 weight % iron.
6. The method of claim 1 , wherein the pre-alloyed Cr—Fe powder comprises 1 weight percent or less of Y, Cu, Ni or Co.
7. The method of claim 1 , further comprising sintering the interconnect in an atmosphere comprising hydrogen after compacting.
8. The method of claim 7 , wherein the sintering is performed at a temperature between 1300-1500° C.
9. The method of claim 7 , wherein the sintering is performed at a temperature between 1400-1500° C.
10. The method of claim 1 , wherein the pre-alloyed Cr—Fe powder is made by purifying the chromium melt made by the aluminothermic process to form the purified chromium melt, and then mixing the purified chromium melt with an iron powder or an iron melt to form the purified chromium-iron melt.
11. The method of claim 10 , wherein providing the pre-alloyed Cr—Fe powder comprises solidifying the purified chromium-iron melt, and mechanically grinding or milling the solidified purified chromium-iron melt to form the pre-alloyed Cr—Fe powder.
12. The method of claim 10 , wherein providing the pre-alloyed Cr—Fe powder comprises atomizing the purified chromium-iron melt, and solidifying the atomized purified chromium-iron melt to form the pre-alloyed Cr—Fe powder.
13. The method of claim 1 , wherein the pre-alloyed Cr—Fe powder is made by purifying the chromium melt made by the aluminothermic process to form the purified chromium melt, and then solidifying the purified chromium melt to form a solid chromium powder.
14. The method of claim 13 , further comprising remelting the solid chromium powder, forming a chromium-iron melt from the remelted solid chromium powder, and forming the pre-alloyed Cr—Fe powder from the chromium-iron melt.
15. The method of claim 1 , wherein providing the pre-alloyed Cr—Fe powder comprises purifying the chromium-iron melt made by the aluminothermic process to form the purified chromium-iron melt.
16. The method of claim 15 , further comprising solidifying the purified chromium-iron melt, and mechanically grinding or milling the solidified chromium-iron melt to form the pre-alloyed Cr—Fe powder.
17. The method of claim 15 , further comprising atomizing the purified chromium-iron melt, and solidifying the atomized chromium-iron melt to form the pre-alloyed Cr—Fe powder.