Method for deposition of ceramic films

Patent metadata

Field	Value
Publication number	US-9561987-B2
Application number	US-99768709-A
Country	US
Kind code	B2
Filing date	Apr 30, 2009
Priority date	Jun 13, 2008
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

The present invention is concerned with methods for the deposition of ceramic films on ceramic or metallic surfaces, particularly the deposition of sub-micron thickness ceramic films such as films of stabilised zirconia and doped ceria such as CGO (cerium gadolinium oxide). The present invention is particularly useful in the manufacture of high and intermediate temperature operating fuel cells including solid oxide fuel cells (SOFC) and also metal supported intermediate temperature SOFC operating in the 450-650° C. range.

First claim

The invention claimed is:

1. A method for depositing at least two layers of an SOFC electrolyte on a substrate that is a main electrolyte layer of the electrolyte, in which the at least two layers are metal oxide crystalline ceramic layers deposited upon the substrate, said substrate being a substantially impermeable mixed ionic electronic conducting electrolyte ceramic material, the method comprising the steps of:
(i) depositing a solution of a soluble salt precursor of a metal oxide crystalline ceramic onto a surface of the substrate to define a layer of said solution of said soluble salt precursor on said surface;
(ii) drying said solution of said soluble salt precursor to define a layer of said soluble salt precursor on said surface;
(iii) heating said soluble salt precursor on said surface to a temperature of between 150 and 600° C. to decompose it and form a layer of metal oxide film on said surface;
(iv) sequentially depositing, drying and heating at between 100 and 600° C. at least one additional layer of the solution of the soluble salt precursor to form a plurality of layers of metal oxide film; and
(v) firing said substrate with said plurality of layers of metal oxide film at a temperature of 500-1100° C. to crystallise said plurality of layers of metal oxide film into a layer of metal oxide crystalline ceramic bonded to said substrate, said layer of metal oxide crystalline ceramic being ion-permeable, electrically insulating, and gas-permeable and said layer of metal oxide crystalline ceramic providing at least a part of an interlayer for the SOFC electrolyte;
(vi) sequentially depositing, drying and heating at between 100 and 600° C. at least one further solution of a further soluble salt precursor of a further metal oxide crystalline ceramic to form a plurality of layers of a further metal oxide film on the interlayer;
(vii) firing said substrate with said plurality of layers of a further metal oxide film at a temperature of 500-1100° C. to crystallise said plurality of layers of a further metal oxide film into a further layer of metal oxide crystalline ceramic, said further layer of metal oxide crystalline ceramic being a mixed ionic electronic conducting electrolyte material and said further layer of metal oxide crystalline ceramic providing at least a part of a barrier layer between the interlayer and a subsequently deposited cathode layer; and
(viii) subsequently depositing the cathode layer;

wherein:
each of steps (ii), (iii), (v) and (vii) is performed in an air atmosphere;
said interlayer of metal oxide crystalline ceramic is thinner than the main electrolyte layer provided by the substantially impermeable mixed ionic electronic conducting electrolyte ceramic material substrate; and
said interlayer is also to electrically insulate the subsequently deposited cathode layer from the main electrolyte layer.

2. A method according to claim 1 , wherein said main electrolyte layer is a CGO electrolyte layer.

3. A method according to claim 1 , wherein:
in steps (i)-(v) said soluble salt precursor is selected from at least one of the group consisting of: zirconium acetylacetonate, scandium nitrate, and yttrium nitrate; and
in steps (vi)-(vii) said further soluble salt precursor is selected from at least one of the group consisting of: cerium acetylacetonate and gadolinium nitrate.

4. A method according to claim 1 , wherein each deposition of a solution of a soluble salt precursor of a metal oxide crystalline ceramic is undertaken with its receiving surface having a temperature of 10-100° C.

5. A method according to claim 1 , wherein said surface of said substrate is substantially impermeable to the soluble salt precursor deposited thereon.

6. A method according to claim 1 , wherein at least one of the layers of metal oxide crystalline ceramic or further metal oxide crystalline ceramic comprises doped stabilised zirconia.

7. A method according to claim 6 , wherein that at least one layer of metal oxide crystalline ceramic or further metal oxide crystalline ceramic is a ceramic selected from the group consisting of: scandia stabilised zirconia (ScSZ), yttria stabilised zirconia (YSZ), scandia ceria co-stabilised zirconia (ScCeSZ), and scandia yttria co-stabilised zirconia (ScYSZ).

8. A method according to claim 1 , wherein at least one of the layers of metal oxide crystalline ceramic or further metal oxide crystalline ceramic comprises rare earth oxide doped ceria.

9. A method according to claim 8 , wherein at least one of the layers of metal oxide crystalline ceramic or further metal oxide crystalline ceramic is a mixed ionic electronic conducting electrolyte material metal oxide crystalline ceramic is selected from the group consisting of: samarium-doped ceria (SDC), gadolinium-doped ceria (GDC), praseodymium doped ceria (PDC), and samaria-gadolinia doped ceria (SGDC).

10. A method according to claim 1 , wherein the soluble salt precursor of steps (i)-(iv) is selected from at least one of the group consisting of: zirconium acetylacetonate, scandium nitrate, yttrium nitrate, cerium acetylacetonate and gadolinium nitrate.

11. A method according to claim 1 , wherein a solvent for the soluble salt precursor or the further soluble salt precursor is selected from at least one of the group consisting of: methanol, ethanol, propanol, methoxypropanol, acetone and butyl carbitol.

12. A method according to claim 1 , additionally comprising prior to step (ii) the step of allowing said solution deposited onto said surface to stand for a period of between 5 and 60 seconds.

13. A method according to claim 1 , wherein said layer of said soluble salt precursor on said surface has a thickness between 10 and 999 nm.

14. A method according to claim 1 , wherein said plurality of layers of metal oxide film each have a thickness less than 1 micron.

15. A method according to claim 1 , wherein said layer of metal oxide crystalline ceramic bonded to said substrate has a thickness between 100 and 999 nm.

16. A method according to claim 1 , wherein said layer of metal oxide crystalline ceramic bonded to said substrate is at least 90% dense.

17. A method according to claim 1 wherein at least 90% of a solvent in the deposited solution of said soluble salt precursor and a solvent in the deposited further solution of said further soluble salt precursor is removed by the end of its respective drying step, prior to its respective heating step.

18. A method according to claim 1 , wherein the deposited solution of the soluble salt precursor of the metal oxide crystalline ceramic and the deposited further solution of the further soluble salt processor of the further metal oxide crystalline ceramic are deposited by a method selected from the group consisting of: spraying, dipping, inkjet printing and spin-coating.

19. A method according to claim 1 , wherein said substrate is CGO, said interlayer is ScYSZ or ScSZ, and said barrier layer is CGO.

20. A surface of a substrate, wherein said substrate is a substantially impermeable mixed ionic electronic conducting electrolyte material, and said surface is a ceramic surface, said surface having deposited upon it at least two layers of metal oxide crystalline ceramic by way of the method according to claim 1 .

21. A method for depositing at least two layers of an SOFC electrolyte on a substrate that is a main electrolyte layer of the electrolyte, in which the at least two layers are metal oxide crystalline ceramic layers deposited upon the substrate, said substrate bein

Assignees

• Bone Adam
• Dawson Richard
• Leah Robert
• Ceres Ip Co Ltd

Inventors

• Bone Adam
• Dawson Richard
• Leah Robert

Classifications

• H01M8/1253

  the electrolyte containing zirconium oxide · CPC title

• H05B6/46

  Dielectric heating (H05B6/64 takes precedence) · CPC title

• C23C18/1204

  inorganic material, e.g. non-oxide and non-metallic such as sulfides, nitrides based compounds · CPC title

• H01M8/126

  the electrolyte containing cerium oxide · CPC title

• C23C18/1225

  Deposition of multilayers of inorganic material · CPC title