Compositions and Methods of Attachment of Thick Environmental Barrier Coatings on CMC Components

• US 20170016335A1
• Filed: 07/13/2015
• Published: 01/19/2017
• Est. Priority Date: 07/13/2015
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Kirby, Glen Harold, Antolino, Nicholas Edward
• Granted Patent: US 10,392,947 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: B32B 2264/10 Inorganic particles
• CPC Class Codes: B32B 2264/12 Mixture of at least two particles made of different materials
• CPC Class Codes: B32B 2315/00 Other materials containing non-metallic inorganic compounds not provided for in groups B32B2311/00 - B32B2313/04
• CPC Class Codes: B32B 2603/00 Vanes, blades, propellers, rotors with blades
• CPC Class Codes: B32B 37/06 characterised by the heating method
• CPC Class Codes: B32B 7/04 Interconnection of layers
• CPC Class Codes: C04B 2103/001 Alkaline earth metal or Mg-compounds
• CPC Class Codes: C04B 2103/0021 Compounds of elements having a valency of 3
• CPC Class Codes: C04B 2235/3427 Silicates other than clay, e.g. water glass
• CPC Class Codes: C04B 35/71 Ceramic products containing macroscopic reinforcing agents C04B35/66 takes precedence ; infiltration of a porous ceramic matrix with a material forming a non-ceramic phase C04B41/00, reaction infiltration with Si in order to form SiC C04B35/573, in order to form Si3N4 C04B35/591
• CPC Class Codes: C04B 35/80 Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4511 using temporarily supports, e.g. decalcomania transfers or mould surfaces
• CPC Class Codes: C04B 41/5024 Silicates C04B41/5022 takes precedence; silico-fluorides C04B41/5018
• CPC Class Codes: C04B 41/5096 Silicon C04B35/573 takes precedence
• CPC Class Codes: C04B 41/52 Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
• CPC Class Codes: C04B 41/522 Multiple coatings, for one of the coatings of which at least one alternative is described
• CPC Class Codes: C04B 41/524 Multiple coatings, comprising a coating layer of the same material as a previous coating layer
• CPC Class Codes: C04B 41/87 Ceramics
• CPC Class Codes: C04B 41/89 : for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: F01D 11/122 : with erodable or abradable material blades having cutting or grinding tips F01D5/20
• CPC Class Codes: F01D 11/125 : with a reinforcing structure
• CPC Class Codes: F01D 25/005 : Selecting particular materials
• CPC Class Codes: F01D 5/147 : Construction, i.e. structural features, e.g. of weight-saving hollow blades F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18
• CPC Class Codes: F01D 5/284 : Selection of ceramic materials
• CPC Class Codes: F01D 5/288 : Protective coatings for blades
• CPC Class Codes: F05D 2220/32 : in gas turbines
• CPC Class Codes: F05D 2230/22 : by sintering
• CPC Class Codes: F05D 2230/90 : Coating; Surface treatment manufacture with deposition of material F05D2230/30
• CPC Class Codes: F05D 2260/95 : Preventing corrosion coating or surface treatment F05D2230/90
• CPC Class Codes: F05D 2300/6033 : Ceramic matrix composites [CMC]
• CPC Class Codes: F05D 2300/611 : Coating
• CPC Class Codes: Y02T 50/60 : Efficient propulsion technologies, e.g. for aircraft

Abstract

A coating system on a CMC substrate is provided, along with methods of its tape deposition onto a substrate. The coating system can include a bond coat on a surface of the CMC substrate; a first rare earth silicate coating on the bond coat; a first sacrificial coating of a first reinforced rare earth silicate matrix on the at least one rare earth silicate layer; a second rare earth silicate coating on the sacrificial coating; a second sacrificial coating of a second reinforced rare earth silicate matrix on the second rare earth silicate coating; a third rare earth silicate coating on the second sacrificial coating; and an outer layer on the third rare earth silicate coating. The first sacrificial coating and the second sacrificial coating have, independently, a thickness of about 4 mils to about 40 mils.

Claims

1. A coating system on a CMC substrate, the coating system comprising:

a first rare earth silicate coating on the substrate, wherein the first rare earth silicate coating comprises at least one rare earth silicate layer;

a first sacrificial coating of a first reinforced rare earth silicate matrix on the at least one rare earth silicate layer, wherein the first sacrificial coating has a thickness of about 4 mils to about 40 mils;

a second rare earth silicate coating on the sacrificial coating, wherein the second rare earth silicate coating comprises at least one rare earth silicate layer;

a second sacrificial coating of a second reinforced rare earth silicate matrix on the second rare earth silicate coating, wherein the second sacrificial coating has a thickness of about 4 mils to about 40 mils; and

a third rare earth silicate coating on the second sacrificial coating, wherein the third rare earth silicate coating comprises at least one rare earth silicate layer;

an outer layer on the third rare earth silicate coating.

2. The coating system of claim 1, wherein the first sacrificial coating has a thickness of about 8 mils to about 25 mils, and wherein the second sacrificial coating has a thickness of about 8 mils to about 25 mils.

3. The coating system of claim 1, wherein the first sacrificial coating has a thickness of about 16 mils to about 24 mils, and wherein the second sacrificial coating has a thickness of about 8 mils to about 25 mils.

4. The coating system of claim 1, wherein the reinforced rare earth silicate matrix of the first sacrificial coating and of the second sacrificial coating comprises a rare earth silicate mixed with a discontinuous phase of barium strontium aluminosilicate.

5. The coating system of claim 1, wherein the reinforced rare earth silicate matrix of the first sacrificial coating and of the second sacrificial coating comprises a rare earth silicate mixed with a discontinuous phase of silicon metal particles.

6. The coating system of claim 1, wherein the reinforced rare earth silicate matrix of the first sacrificial coating and of the second sacrificial coating comprises a rare earth disilicate.

7. The coating system of claim 1, wherein the reinforced rare earth silicate matrix of the first sacrificial coating and of the second sacrificial coating comprises a rare earth monosilicate.

8. The coating system of claim 1, wherein the reinforced rare earth silicate matrix of the first sacrificial coating and of the second sacrificial coating comprises a mixture of a rare earth monosilicate and a rare earth disilicate.

9. The coating system of claim 1, further comprising:

a bond coat on a surface of the CMC substrate between the CMC substrate and the first rare earth silicate coating, wherein the bond coat is a silicon bond coat.

10. The coating system of claim 1, wherein the first rare earth silicate coating, the second rare earth silicate coating, and the third rare earth silicate coating have a substantially identical composition.

11. A blade, comprising:

an airfoil comprising a CMC substrate and defining a blade tip;

wherein the blade tip has the coating system of claim 1 thereon.

12. The blade as in claim 11, wherein the blade is a turbine blade comprising:

a shank defining a dovetail; and

a platform separating the airfoil from the shank,

wherein the blade tip has the coating system of claim 1 thereon.

13. A method of tape deposition of a sacrificial coating on a CMC substrate, the method comprising:

applying a first matrix material onto a surface of a first film, wherein the first matrix material comprises a mixture of a rare earth silicate powder, a sintering aid, and a solvent;

drying the first matrix material to remove the solvent forming a first tape having a film side and a matrix side;

applying the first tape onto the CMC substrate with the matrix side facing the CMC substrate;

applying a second matrix material onto a surface of a second film, wherein the second matrix material comprises a mixture of a rare earth silicate powder, a sintering aid, and a solvent;

applying the second tape onto the CMC substrate with the matrix side facing the CMC substrate; and

sintering the first tape and the second tape to bond the first matrix material to the CMC substrate via a first bonding layer and to bond the second matrix material to the first matrix material via a second bonding layer.

14. The method of claim 13, wherein the first matrix material further comprises a plurality of coarse particles, and wherein the coarse particles comprise coarse BSAS particles, silicon particles, or a mixture thereof, and wherein the coarse particles have an average particle size of about 5 microns to about 100 microns.

15. The method of claim 14, wherein the coarse particles comprise about 30% to about 65% by volume of the matrix material after drying, with the balance being the rare earth silicate powder and the sintering aid.

16. The method of claim 14, wherein the first matrix material further comprises an organic binder and a plasticizer.

17. The method of claim 16, wherein the organic binder comprises polyvinyl butyral, and wherein the plasticizer comprises dibutyl phthalate or dipropylene glycol dibenzoate.

18. The method of claim 14, wherein the second matrix material further comprises a plurality of coarse particles, and wherein the coarse particles comprise coarse BSAS particles, silicon particles, or a mixture thereof.

19. The method of claim 18, wherein the coarse particles comprise about 30% to about 65% by volume of the matrix material after drying, with the balance being the rare earth silicate powder and the sintering aid.

20. The method of claim 14, wherein the first tape forms a first sacrificial coating of a first reinforced rare earth silicate matrix having a thickness of about 4 mils to about 40 mils;

and wherein the second tape forms a second sacrificial coating of a second reinforced rare earth silicate matrix having a thickness of about 4 mils to about 40 mils.