Method for making dense crack free thin films

• US 20030021900A1
• Filed: 06/03/2002
• Published: 01/30/2003
• Est. Priority Date: 07/31/1999
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Visco, Steven J., Jacobson, Craig P., De Jonghe, Lutgard C.
• Granted Patent: US 7,163,713 B2
• Time in Patent Office: Days
• US Class Current: 427/376.2
• CPC Class Codes: B01D 2257/108 Hydrogen
• CPC Class Codes: B01D 53/326 in electrochemical cells
• CPC Class Codes: C04B 2111/00801 Membranes; Diaphragms
• CPC Class Codes: C04B 2111/00853 in electrochemical cells or batteries, e.g. fuel cells
• CPC Class Codes: C04B 35/016 based on manganites
• CPC Class Codes: C04B 38/0038 by superficial sintering or bonding of particulate matter
• CPC Class Codes: C04B 38/0054 the pores being microsized or nanosized
• CPC Class Codes: C04B 38/0074 expressed as porosity percentage
• CPC Class Codes: C25B 9/00 Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 2300/0074 Ion conductive at high temperature
• CPC Class Codes: H01M 4/9025 Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
• CPC Class Codes: H01M 4/9033 Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
• CPC Class Codes: H01M 4/9066 of metal-ceramic composites or mixtures, e.g. cermets
• CPC Class Codes: H01M 8/1213 characterised by the electrode/electrolyte combination or the supporting material
• CPC Class Codes: H01M 8/1226 characterised by the supporting layer
• CPC Class Codes: H01M 8/1231 with both reactants being gaseous or vaporised
• CPC Class Codes: H01M 8/124 characterised by the process of manufacturing or by the material of the electrolyte
• CPC Class Codes: H01M 8/1246 the electrolyte consisting of oxides
• CPC Class Codes: H01M 8/1253 the electrolyte containing zirconium oxide
• CPC Class Codes: H01M 8/126 : the electrolyte containing cerium oxide
• CPC Class Codes: H01M 8/1266 : the electrolyte containing bismuth oxide
• CPC Class Codes: H01M 8/1286 : Fuel cells applied on a support, e.g. miniature fuel cells deposited on silica supports
• CPC Class Codes: H01M 8/2432 : Grouping of unit cells of planar configuration
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

Claims

1. A method for producing a high density, crack free thin ceramic film comprising:

depositing at least one thin film of a ceramic material having a green density on a substrate, compressing said thin ceramic film such that the green density is increased and firing the thin ceramic film/substrate laminate.

2. A method for producing a high density, crack free thin ceramic film according to claim 1, wherein the substrate is a non-porous dense substrate.

3. A method for producing a high density, crack free thin ceramic film according to claim 1, wherein the compressing step is accomplished by uniaxial mechanical pressing, isostatic pressing or air/vaccum pressure.

4. A method for producing a high density, crack free thin ceramic film according to claim 1, wherein the compressing step is accomplished by uniaxial mechanical pressing or air/vaccum pressure.

5. A method for producing a high density, crack free thin ceramic film according to claim 1, wherein the substrate is porous.

6. A method for producing a high density, crack free thin ceramic film according to claim 1, wherein the substrate is a porous lanthanum strontium manganite substrate.

7. A method for producing a high density, crack free thin ceramic film according to claim 1, wherein the firing is conducted at a temperature sufficient to substantially sinter and densify the layers.

8. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the sintering is conducted at about 1000°

C. to about 1500°

C.

9. A method for producing a high density, crack free thin ceramic film as claimed in claim 8, wherein the sintering is conducted at about 1200°

C. to about 1400°

C.

10. A method for producing a high density, crack free thin ceramic film as claimed in claim 9, wherein the sintering is conducted at about 1250°

C. to about 1350°

C.

11. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the resulting thin ceramic film is gas-tight and greater than about 90% densified.

12. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the resulting thin ceramic film is gas-tight and greater than about 95% densified.

13. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the thin ceramic film layer is no more than 2% porous.

14. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the thin ceramic film layer is about 1 to 50 microns thick.

15. A method for producing a high density, crack free thin ceramic film as claimed in claim 14, wherein the thin ceramic film layer is about 3 to 30 microns thick.

16. A method for producing a high density, crack free thin ceramic film as claimed in claim 15, wherein the thin ceramic film layer is about 5 to 20 microns thick.

17. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the substrate is planar.

18. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the substrate is tubular.

19. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the substrate is hexagonal.

20. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein said substrate is an alloy selected from the group consisting of a low-chromium ferritic steel, an intermediate-chromium ferritic steel, a high-chromium ferritic steel, a chrome-based alloy, and chrome-containing nickel-based Inconel alloy.

21. A method for producing a high density, crack free thin ceramic film as claimed in claim 20, wherein said alloy is selected from the group consisting of Cr5Fe1Y and Inconel 600.

22. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein said substrate material is a cermet selected from the group consisting of at least one of La_1-xSr_xMn_yO_3-δ

(1≧

X0.05) (0.95≦

y≦

1.15) (“

LSM”

), La_1-xSr_xCoO_3-δ

(1≧

X≧

0.10) (“

LSC”

), SrCo_1-xFe_xO_3-^δ

(0.30≧

X≧

0.20), La_0.6Sr_0.4Co_0.6Fe_0.4O_3-^δ

, Sr_0.7Ce_0.3MnO_3-δ

, LaNi_0.6Fe_0.4O_3-δ

, Sm_0.5Sr_0.5CoO_3-δ

, yttria stabilized zirconia (YSZ), scandia stabilized zirconia (SSZ), (CeO₂)_0.8(Gd₂O₃)_0.2 (CGO), La_0.8Sr_0.2Ga_0.85Mg_0.15O_2.825 (LSGM20-15), (Bi₂O₃)_0.75(Y₂O₃)_0.25 and alumina, in combination with at least one of transition metals Cr, Fe, Cu, Ag, an alloy thereof, a low-chromium ferritic steel, an intermediate-chromium ferritic steel, a high-chromium ferritic steel, a chrome-based alloy, and chrome-containing nickel-based Inconel alloy.

23. A method for producing a high density, crack free thin ceramic film as claimed in claim 22, wherein the LSM is selected from the group consisting of La_0.8Sr_0.2MnO_3-δ

, La_0.65Sr_0.30MnO_3-δ

, La_0.45Sr_0.55MnO_3-δ

.

24. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein said ceramic thin film comprises at least one of yttria stabilized zirconia (YSZ), scandia stabilized zirconia (SSZ), doped cerium oxide including (CeO₂)_0.8(Gd₂O₃)_0.2(CGO), La_0.8Sr_0.2Ga_0.85Mg_0.15O_2.825 (LSGM20-15) and (Bi₂O₃)_0.75(Y₂O₃)_0.25.

25. A method for producing a high density, crack free thin ceramic film as claimed in claim 24, wherein said electrolyte is yttria stabilized zirconia.

26. A method for producing a high density, crack free thin ceramic film as claimed in claim 25, wherein said yttria stabilized zirconia is (ZrO₂)_x(Y₂O₃)_y where (0.88≧

X≧

0.97) and (0.03≦

y≦

0.12).

27. A method for producing a high density, crack free thin ceramic film as claimed in claim 26, wherein said yttria stabilized zirconia is at least one of (ZrO₂)_0.92(Y₂O₃)_0.08 and (ZrO₂)_0.90(Y₂O₃)_0.10.

28. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein the thin ceramic film is a mixed ionic electronic conductor.

29. A method for producing a high density, crack free thin ceramic film as claimed in claim 28, wherein said electrolyte comprises at least one of SrCo_1-xFe_XO_3-^δ

(0.30≧

X≧

0.20), La_0.6Sr_0.4Co_0.6Fe_0.4O_3-^δ

, Sm_0.5Sr_0.5CoO_3-δ

and La_1-xSr_xCoO_3-δ

.

30. A method for producing a high density, crack free thin ceramic film as claimed in claim 29, wherein said electrolyte is SrCo_0.75Fe_0.25O_3-^δ

.

31. A method for producing a high density, crack free thin ceramic film as claimed in claim 1, wherein more than one thin ceramic film layer is deposited on the substrate.

32. A solid oxide fuel cell made according to the process of claim 1.