Cmas-resistant barrier coatings

Patent metadata

Field	Value
Publication number	US-2020123071-A1
Application number	US-201916657504-A
Country	US
Kind code	A1
Filing date	Oct 18, 2019
Priority date	Oct 18, 2018
Publication date	Apr 23, 2020
Grant date	—

Abstract

An example article includes a substrate and a barrier coating on the substrate. The barrier coating includes a matrix including a rare-earth disilicate extending from an inner interface facing the substrate to an outer surface opposite the inner interface. The barrier coating includes a graded volumetric distribution of rare-earth oxide rich (REO-rich) phase regions in the matrix along a direction from the inner interface to the outer surface. The graded volumetric distribution defines a first volumetric density of the REO-rich phase regions at a first region of the matrix adjacent the outer surface. The graded volumetric distribution defines a second volumetric density of the REO-rich phase regions at a second region of the matrix adjacent the inner surface. The second volumetric density is different from the first volumetric density. An example technique includes forming the barrier coating on the substrate of a component.

First claim

What is claimed is:

1 . An article comprising:
a substrate; a barrier coating on the substrate, the barrier coating comprising:
a matrix comprising a rare-earth disilicate, the matrix extending from an inner interface facing the substrate to an outer surface opposite the inner interface; and
a graded volumetric distribution of rare-earth oxide rich (REO-rich) phase regions in the matrix along a direction from the inner interface to the outer surface, wherein the graded volumetric distribution defines a first volumetric density of the plurality of REO-rich phase regions at a first region of the matrix adjacent the outer surface and a second volumetric density of the plurality of REO-rich phase regions at a second region of the matrix adjacent the inner interface, and wherein the second volumetric density is different from the first volumetric density.

2 . The article of claim 1 , wherein the barrier coating defines a coating thickness along the direction from the outer surface to the inner interface, wherein the first region defines a first thickness along the direction, wherein the second region defines a second thickness along the direction, wherein a ratio of the first thickness to the coating thickness is greater than about 0.1, and wherein a ratio of the second thickness to the coating thickness is greater than about 0.1.

3 . The article of claim 2 , wherein a sum of the ratio of the first thickness to the coating thickness and the ratio of the second thickness to the coating thickness is 1.

4 . The article of claim 1 , wherein the coating thickness is between about 50 micrometers and about 500 micrometers.

5 . The article of claim 1 , wherein a ratio of the second volumetric density to the first volumetric density is less than 1.

6 . The article of claim 1 , wherein a ratio of the first volumetric density to the second volumetric density is less than 1.

7 . The article of claim 1 , wherein the second region comprises less than 10% by volume of the REO-rich phase regions, wherein a third region between the second region and the first region comprises between about 10% and about 30% by volume of the REO-rich phase regions, and wherein the first region comprises more than about 30% by volume of the REO-rich phase regions.

8 . The article of claim 7 , wherein the second region defines a thickness of about 50 microns in the direction from the outer surface to the inner interface, wherein the third region defines a thickness of about 50 microns in the direction from the outer surface to the inner interface, and wherein the first region defines a thickness of about 25 microns in the direction from the outer surface to the inner interface.

9 . The article of claim 1 , wherein the REO-rich phase regions include rare-earth oxide in excess of stoichiometric rare-earth disilicate.

10 . The article of any claim 9 , wherein the REO-rich phase regions include rare-earth oxide in excess of stoichiometric rare-earth monosilicate.

11 . The article of claim 1 , wherein the REO-rich phase regions are configured to disperse REO-rich precipitates into the matrix in response to reacting with calcia magnesia alumina-silicate (CMAS).

12 . The article of claim 11 , wherein the REO-rich precipitates are configured to react with SiO 2 to form a rare-earth disilicate.

13 . The article of claim 1 , wherein the rare-earth disilicate comprises ytterbium disilicate, and wherein the REO-rich phase regions comprise free ytterbium oxide.

14 . The article of claim 13 , wherein the REO-rich phase regions comprise ytterbium monosilicate.

15 . The article of claim 1 , further comprising a bond coat on at least a portion of the substrate, wherein the barrier coating is on the bond coat.

16 . The article of claim 1 , wherein the article comprises a gas turbine engine component, and wherein the barrier coating comprises an environmental barrier coating.

17 . A method comprising:
forming a barrier coating on a substrate of a component, wherein the barrier coating comprises:
a matrix comprising a rare-earth disilicate, the matrix extending from an inner interface facing the substrate to an outer surface opposite the inner interface; and
a graded volumetric distribution of rare-earth oxide rich (REO-rich) phase regions in the matrix along a direction from the inner interface to the outer surface, wherein the graded volumetric distribution defines a first volumetric density of the plurality of REO-rich phase regions at a first region of the matrix adjacent the outer surface and a second volumetric density of the plurality of REO-rich phase regions at a second region of the matrix adjacent the inner interface, and wherein the second volumetric density is different from the first volumetric density.

18 . The method of claim 17 , further comprising forming a bond coat on the substrate, and forming the barrier coating on the bond coat.

19 . The method of claim 17 , wherein the rare-earth disilicate comprises ytterbium disilicate, and wherein the forming the barrier coating comprises at least one of:
thermally spraying a composition consisting essentially of ytterbium disilicate towards the substrate using thermal spray parameters selected to volatilize a selected amount of silica, thermally spraying a composition comprising ytterbium disilicate towards the substrate, thermally spraying a composition comprising ytterbium disilicate and at least one of ytterbium monosilicate or ytterbium oxide towards the substrate, depositing a composition comprising ytterbium disilicate and at least one of ytterbium monosilicate or ytterbium oxide from a slurry, depositing a composition consisting essentially of ytterbium disilicate from a slurry depositing a composition comprising ytterbium disilicate and at least one of ytterbium monosilicate or ytterbium oxide using a vapor deposition process, depositing a composition consisting essentially of ytterbium disilicate using a vapor deposition process, depositing a composition comprising ytterbium disilicate and at least one of ytterbium monosilicate or ytterbium oxide using an electrophoretic deposition process, or depositing a composition consisting essentially of ytterbium disilicate using an electrophoretic deposition process.

20 . The method of claim 19 , wherein the REO-rich phase regions comprise free ytterbium oxide, and wherein forming the barrier coating comprises controlling the thermal spraying to form at least one of ytterbium oxide or ytterbium monosilicate from ytterbium disilicate in the composition.

Assignees

• Rolls Royce Corp
• Rolls Royce Plc

Inventors

• Ndamka Ngunjoh Lawrence
• Li Li
• Gong Stephanie
• Bolcavage Ann
• Blair Taylor K
• Golden Robert

Classifications

• C04B41/4543

  by spraying, e.g. by atomising · CPC title

• C04B41/89

  for obtaining at least two superposed coatings having different compositions · CPC title

• C23C28/04

  only coatings of inorganic non-metallic material · CPC title

• C04B2111/00405

  Materials with a gradually increasing or decreasing concentration of ingredients or property from one layer to another · CPC title

• C23C28/048

  with layers graded in composition or physical properties · CPC title