Duplex coating for SOFC interconnect
View Patent ↗A coated interconnect for a solid oxide fuel cell including an interconnect substrate comprising iron and chromium and a first metal oxide coating formed over an air side of the interconnect substrate. The first metal oxide coating is formed from powder particles, wherein substantially all the powder particles have a particle size less than 22 microns.
1. A coated interconnect for a solid oxide fuel cell, comprising:
an interconnect substrate comprising iron and at least 90% chromium; and
a first metal oxide coating formed over an air side of the interconnect substrate;
wherein the first metal oxide coating is formed from powder particles, wherein substantially all the powder particles have a particle size less than 22 microns.
2. The coated interconnect of claim 1 , wherein at least 95% of the powder particles have a particle size less than 25 microns.
3. The coated interconnect of claim 1 , wherein the first metal oxide coating is formed from powder particles having a powder particle size distribution with D10 of particles of size 6 to 12 μm; D50 of particles of size 11 to 17 μm; D90 of particles of size 17 to 23 μm; D95 of particles of size 20 to 25 μm; and 2% of the particles having a minimum size <5 μm.
4. The coated interconnect of claim 1 , wherein first metal oxide coating comprises a composite perovskite and spinel metal oxide coating.
5. The coated interconnect of claim 4 , wherein the perovskite to the spinel weight ratio ranges between 60:40 and 80:20.
6. The coated interconnect of claim 5 , wherein the perovskite to the spinel weight ratio ranges between 67:33 and 73:27.
7. The coated interconnect of claim 4 , wherein the spinel comprises manganese cobalt oxide having a formula Mn 2−x Co I+x O 4 , where 0≦x≦1, and the perovskite comprises lanthanum strontium manganate having a formula La 1−x Sr x MnO 3 (LSM), where 0.1≦x≦0.3.
8. The coated interconnect of claim 1 , further comprising a second metal oxide coating formed under the first metal oxide coating and over the air side of the interconnect substrate.
9. The coated interconnect of claim 8 , wherein the second metal oxide coating is formed from powder particles having a powder particle size distribution with D10 of particles of size 12 to 18 μm; D50 of particles of size 20 to 30 μm; D90 of particles of size 35 to 45 μm; D95 of particles of size 40 to 50 μm; and 2% of the particles having a minimum size <11 μm.
10. The coated interconnect of claim 8 , wherein at least 95% of the powder particles of the second metal oxide coating have a particle size less than 40 microns.
11. The coated interconnect of claim 8 , wherein first metal oxide coating comprises a first composite perovskite and spinel metal oxide coating, and the second metal oxide coating comprises a second composite spinel and perovskite metal oxide coating.
12. The coated interconnect of claim 8 , wherein the first metal oxide coating has a thickness between 25-50 microns and the second metal oxide coating has a thickness between 25-75 microns.
13. The coated interconnect of claim 8 , wherein the first metal oxide coating has a first thickness, the second metal oxide coating has a second thickness, and the second thickness is 100%-200% greater than the first thickness.
14. A method of making a coated interconnect comprising:
providing an interconnect substrate comprising and at least 90% Cr; and
coating an air side of the interconnect substrate with a first metal oxide coating formed from metal oxide powder particles over an air side of the interconnect substrate,
wherein substantially all the metal oxide powder particles have a particle size less than 22 microns.
15. The method of claim 14 , wherein the first metal oxide coating is applied with an air plasma coating process.
16. The method of claim 14 , wherein at least 95% of the metal oxide powder particles have a particle size less than 22 microns.
17. The method of claim 14 , wherein first metal oxide coating comprises a composite perovskite and spinel metal oxide coating, the spinel comprises manganese cobalt oxide and the perovskite comprises lanthanum strontium manganate.
18. The method of claim 17 , wherein the perovskite to the spinel weight ratio ranges between 60:40 and 80:20.
19. The method of claim 14 , further comprising coating the air side of the interconnect substrate with a second metal oxide coating prior to the coating the air side of the interconnect substrate with the first metal oxide coating.
20. The method of claim 19 , wherein:
the first metal oxide coating is formed over the second metal oxide coating; and
the second metal oxide coating is formed from powders particles.
21. The method of claim 20 , wherein the first metal oxide coating has a first thickness, the second metal oxide coating has a second thickness, and the second thickness is 100%-200% greater than the first thickness.