PROTECTIVE INTERNAL COATINGS FOR POROUS SUBSTRATES

• US 20130004309A1
• Filed: 09/10/2012
• Published: 01/03/2013
• Est. Priority Date: 03/02/2011
• Status: Abandoned Application

• Current Assignee: Applied Thin Films, Inc.
• Original Assignee: Applied Thin Films, Inc.
• Inventors: Sambasivan, Sankar, Chapman, Francis Richard, Kaul, Vikram Sharad
• Application Number:
  US13/608,773
• Publication Number:
  US 20130004309A1
• Time in Patent Office: Days
• US Class Current: 415/208.1
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 35/14 based on silica
• CPC Class Codes: C04B 35/195 Alkaline earth aluminosilicates, e.g. cordierite or anorthite
• CPC Class Codes: C04B 35/522 Graphite C04B35/536 takes precedence
• CPC Class Codes: C04B 35/565 based on silicon carbide
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/806 The matrix of the ceramic products consisting of non-oxides only
• CPC Class Codes: C04B 35/83 Carbon fibres in a carbon matrix
• CPC Class Codes: C04B 38/00 Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof treating slag with gases or gas generating material C04B5/06 ; expanded graphite C04B35/536
• CPC Class Codes: C04B 38/0054 the pores being microsized or nanosized
• CPC Class Codes: C04B 38/0096 Pores with coated inner walls
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4515 application under vacuum or reduced pressure
• CPC Class Codes: C04B 41/5092 Phosphate cements
• CPC Class Codes: C04B 41/85 with inorganic materials
• CPC Class Codes: C23C 18/1216 Metal oxides C23C18/1212 takes precedence
• CPC Class Codes: C23C 18/1229 Composition of the substrate
• CPC Class Codes: C23C 18/125 Process of deposition of the inorganic material
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: F05D 2300/514 : Porosity
• CPC Class Codes: F05D 2300/6033 : Ceramic matrix composites [CMC]
• CPC Class Codes: Y02T 50/60 : Efficient propulsion technologies, e.g. for aircraft
• CPC Class Codes: Y10T 428/249921 : Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/249967 : Inorganic matrix in void-containing component
• CPC Class Codes: Y10T 428/249969 : Of silicon-containing material [e.g., glass, etc.]
• CPC Class Codes: Y10T 428/24997 : Of metal-containing material
• CPC Class Codes: Y10T 428/249978 : Voids specified as micro
• CPC Class Codes: Y10T 428/268 : Monolayer with structurally defined element

Abstract

A material contains open pores in which the channels and pores that are internally coated with at least one layer of phosphorus-containing alumina. Such material is formed by infiltrating a porous material one or more times with a non-colloidal, low-viscosity liquid coating precursor, drying, and curing the coating precursor to form a phosphorus-containing alumina layer within pores of the material.

Claims

1. A material comprising a porous substrate containing open pores and channels and comprising interconnected mesopores and micropores, in which the pores and channels are internally coated with at least one layer of phosphorus-containing alumina.

2. A material of claim 1 in which the internal coating layer is at least 5 nm thick.

3. A material of claim 1 in which open porosity of a coated substrate is at least 40% of the open porosity of an uncoated substrate.

4. A material of claim 1 in which density an internally coated substrate is increased by no more than 10% over an uncoated substrate.

5. A material of claim 1 in which pore or channel constrictions within the porous substrate are blocked.

6. A material of claim 1 in which the internal coating remains stable at 1000°

C.

7. A material of claim 1 in which the internal coating layer contains at least two sublayers.

8. A material of claim 7 in which each sublayer does not cover all of total surface area within the internal open pores and channels.

9. A material of claim 1 in which the phosphorus-containing alumina has aluminum to phosphorus atomic ratios of 2:

1 to 15;

1.

10. A material of claim 1 in which the porous substrate comprises a ceramic material or coating, a ceramic matrix composite, or a metal or metal alloy.

11. A material of claim 1 in which the porous substrate comprises a ceramic thermal barrier coating bonded to a metal.

12. A material of claim 1 in which the porous substrate comprises a plasma spray coating, electron beam physical vapor deposition coating, metallurgical overlay coating, or a slurry coating bonded to metal or ceramic or ceramic composite.

13. A material of claim 1 in which the porous substrate comprises graphite;

a silicon carbide;

a carbon-carbon composite, a carbon-silicon carbide composite, or a silicon carbide-silicon carbide composite;

or a ceramic refractory or tile.

14. A material of claim 1 bonded to a turbine blade, a vane, or a shroud.

15. A method to form a material having an internally coated porous substrate surface comprising:

a) contacting a porous substrate containing open pores and channels and comprising interconnected mesopores and micropores with a non-colloidal, low viscosity solution, having a viscosity lower than 100 centistokes, of a phosphorus-containing alumina coating precursor, formed by combining solutions of an aluminum salt and a phosphate ester, such that the coating precursor infiltrates and internally coats the open pores and channels; and

b) drying and curing the phosphorus-containing alumina coating precursor to form a layer of phosphorus-containing alumina onto internal surfaces of the pores.

16. A method of claim 15 in which a pressure differential is applied to the porous substrate by placing the substrate under vacuum conditions before contacting with the coating solution.

17. A method of claim 15 in which the alcohol is methanol, ethanol, or a mixture thereof.

18. A method of claim 15 in which steps a) and b) are repeated at least twice.

19. A method of claim 15 in which phosphorus-containing alumina has an aluminum to phosphorus atomic ratio of 4 to 10.

20. A method to protect a porous substrate surface containing open pores from environmental conditions comprising:

a) contacting a porous substrate containing open pores and channels and comprising interconnected mesopores and micropores under external pressure conditions with a non-colloidal, low viscosity solution of a phosphorus-containing alumina coating precursor, formed by combining solutions of an aluminum salt and a phosphate ester, such that the coating precursor infiltrates and internally coats the open pores; and

b) drying and curing the phosphorus-containing alumina coating precursor to form a continuous layer of phosphorus-containing alumina onto internal surfaces of the pores.