Combustion chemical vapor deposition of films and coatings

• US 5,652,021 A
• Filed: 04/03/1995
• Issued: 07/29/1997
• Est. Priority Date: 03/24/1993
• Status: Expired due to Term

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Hunt, Andrew T., Cochran, Joe K., Carter, William Brent
• Primary Examiner(s): King, Roy V.
• Application Number:
  US08/416,435
• Time in Patent Office: 848 Days
• Field of Search: 427/569, 427/573, 427/248.1, 427/255.1, 427/255.2, 427/255.3, 427/452, 427/453, 427/455, 427/450
• US Class Current: 427/248.1
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/408 of copper or solid solutions thereof
• CPC Class Codes: C23C 16/409 of the type ABO3 with A representing alkali, alkaline earth metal or lead and B representing a refractory metal, nickel, scandium or a lanthanide
• CPC Class Codes: C23C 16/448 characterised by the method used for generating reactive gas streams, e.g. by evaporation or sublimation of precursor materials
• CPC Class Codes: C23C 16/453 passing the reaction gases through burners or torches, e.g. atmospheric pressure CVD C23C16/513 takes precedence; for flame or plasma spraying of coating material in the molten state C23C4/00
• CPC Class Codes: C23C 16/513 using plasma jets
• CPC Class Codes: C30B 25/10 Heating of the reaction chamber or the substrate
• CPC Class Codes: C30B 25/105 by irradiation or electric discharge
• CPC Class Codes: C30B 29/22 Complex oxides
• CPC Class Codes: C30B 29/225 based on rare earth copper oxides, e.g. high T-superconductors
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method for applying coatings to substrates using combustion chemical vapor deposition by mixing together a reagent and a carrier solution to form a reagent mixture, igniting the reagent mixture to create a flame, or flowing the reagent mixture through a plasma torch, in which the reagent is at least partially vaporized into a vapor phase, and contacting the vapor phase of the reagent to a substrate resulting in the deposition, at least in part from the vapor phase, of a coating of the reagent which can be controlled so as to have a preferred orientation on the substrate, and an apparatus to accomplish this method.

Claims

1. A method for applying a coating selected from the group consisting of a metal, metal oxide, nitride, carbide, fluoride, boride and carbonate to substrates using chemical vapor deposition comprising the steps of:

(a) providing a substrate having at least one surface to be coated;

(b) selecting a reagent and a carrier medium and mixing together said reagent and said carrier medium to form a reagent mixture, the reagent being selected such that at least a portion of the reagent forms the metal, metal oxide, nitride, carbide, fluoride, boride and carbonate coating;

(c) providing a combustion means;

(d) providing an oxidant to said combustion means to assist in combusting said reagent mixture;

(e) introducing said reagent mixture into said combustion means and combusting said reagent mixture thereby producing a flame which produces radiant energy and hot gases and vaporizing at least a portion of said reagent into a vapor phase;

(f) locating said substrate in a zone located relative to said flame such that the substrate is heated by said radiant energy and said hot gases of said flame sufficiently to allow adhesion of said vapor phase onto said substrate to form the metal, metal oxide, nitride, carbide, fluoride, boride and carbonate coating on said substrate; and

(g) contacting said vapor phase of said reagent with said substrate in said zone resulting in the deposition from said vapor phase of the metal, metal oxide, nitride, carbide, fluoride, boride and carbonate coating onto said substrate.

2. The method as claimed in claim 1, wherein said coating is a crystalline film.

3. The method as claimed in claim 1, wherein said reagent mixture is a liquid solution and said coating is a non-crystalline film.

4. The method as claimed in claim 1, wherein said reagent mixture is flammable.

5. The method as claimed in claim 2, wherein a fuel capable of combustion is supplied to said combustion means to fuel said combusting of said reagent mixture.

6. The method as claimed in claim 3, wherein a fuel capable of combustion is supplied to said combustion means to fuel said combusting of said reagent mixture.

7. The method as claimed in claim 2, wherein said carrier medium is a liquid organic solvent.

8. The method as claimed in claim 3, wherein said carrier medium is a liquid organic solvent.

9. The method as claimed in claim 2, wherein said reagent is a gas, a vapor, or a liquid and said carrier medium is a gas, a vapor, or a liquid.

10. The method as claimed in claim 3, wherein said reagent is a gas, a vapor, or a liquid and said carrier medium is a gas, a vapor, or a liquid.

11. The method as claimed in claim 9, wherein said reagent mixture is a liquid solution and said vapor phase consists essentially of vapors of said reagent.

12. The method as claimed in claim 11, wherein said coating comprises a combination of vapor deposited and spray pyrolysis deposited film of said reagent.

13. The method as claimed in claim 12, wherein said coating is comprised essentially of spray pyrolysis deposited film of said reagent.

14. The method as claimed in claim 7, wherein said reagent mixture is a liquid solution which comprises solid particles of said reagent and said vapor comprises vapors of said reagent and solid particles of said reagent.

15. The method as claimed in claim 11 wherein said coating is an essentially heterogeneously nucleated film comprising said reagent.

16. The method as claimed in claim 14 wherein said coating is a film comprising solid particles of said reagent and said reagent.

17. The method as claimed in claim 16, wherein said coating comprises less than about 50% by volume of said solid particles.

18. The method as claimed in claim 7, wherein said coating is less than about 1000 microns in thickness.

19. The method as claimed in claim 18, wherein said coating is less than about 100 microns in thickness.

20. The method as claimed in claim 1, wherein said substrate is heated predominantly by the heat of combustion produced by combusting said reagent mixture.

21. The method as claimed in claim 1, wherein said substrate is heated predominantly by a secondary heat source.

22. The method as claimed in claim 7, wherein said coating is thermodynamically stable in an oxidizing environment having a temperature of approximately 300°

C. or higher.

23. The method as claimed in claim 7, wherein said coating is not thermodynamically stable in an oxidizing environment having a temperature of approximately 300°

C. or higher.

24. The method as claimed in claim 22, wherein said reagent is a metalorganic compound.

25. The method as claimed in claim 23, wherein additional reactants are supplied to said combustion means proximate to but just beyond said flame.

26. The method as claimed in claim 7, wherein said reagent mixture further comprises non-reactive particles which deposit on said substrate with said coating.

27. The method as claimed in claim 26, wherein said non-reactive particles are molten when striking said substrate.

28. The method as claimed in claim 1, wherein said flame has a temperature of between about 300°

C., and 2800°

C., said substrate has a surface temperature of between about 100°

C. and 2200°

C., and said deposition occurs at a pressure of between about 10 tort and 10,000 torr.

29. The method as claimed in claim 28, wherein said coating is deposited on said substrate at a deposition rate of between about 0.1 μ

m/hr and 1000 μ

m/hr.

30. The method as claimed in claim 29, wherein said substrate has a surface temperature of between about 400°

C. and 1300°

C.

31. The method as claimed in claim 3, wherein said coating is less than about 1 mm in thickness.

32. The method as claimed in claim 31, wherein said flame has a temperature of between about 300°

C. and 2800°

C., said substrate has a surface temperature of between about 100°

C. and 1500°

C., and said deposition occurs at a pressure of between about 10 torr and 10,000 torr.

33. The method as claimed in claim 32, wherein said coating is deposited on said substrate at a deposition rate of between about 0.1 μ

m/hr and 1000 μ

m/hr.

34. The method as claimed in claim 33, wherein said substrate has a surface temperature of between about 400°

C. and 1300°

C.

35. A method for applying, a coating selected from the group consisting of a metal, metal oxide, nitride, carbide, fluoride, boride and carbonate to substrates using chemical vapor deposition comprising the steps of:

(a) providing a substrate having at least one surface to be coated;

(b) selecting a reagent and a carrier medium and mixing together said reagent and said carrier medium to form a reagent mixture, the reagent being selected such that at least a portion of the reagent forms the metal, metal oxide, nitride, carbide, fluoride, boride and carbonate coating;

(c) combusting at least a portion of said reagent mixture thereby producing a flame which produces radiant energy and hot gases and vaporizing at least a portion of said reagent into a vapor phase;

(d) locating said substrate in a zone such that the substrate is heated by said radiant energy and said hot gases of said flame sufficiently to allow adhesion of said vapor phase onto said substrate to form the coating on said substrate; and

(e) contacting said vapor phase of said reagent with said substrate in said zone resulting in the deposition from said vapor phase of the metal, metal oxide, nitride, carbide, fluoride, boride and carbonate coating onto said substrate.