Recession resistant ceramic matrix composites and environmental barrier coatings

Patent metadata

Field	Value
Publication number	US-2016153288-A1
Application number	US-201313833822-A
Country	US
Kind code	A1
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

The disclosure relates generally to recession resistant gas turbine engine articles that comprise a silicon containing substrate, and related coatings and methods. The present disclosure is directed, inter alia, to an engine article comprising a silicon substrate which is coated with a chemically stable porous oxide layer. The present disclosure also relates to articles comprising a substrate and a bond coat on top comprising a two phase layer of interconnected silicon and interconnected oxide, followed by a layer of silicon. The present disclosure further relates to a recession resistant article comprising an oxide in a silicon containing substrate, such that components of the silicon containing substrate is interconnected with oxides dispersed in the substrate and form the bulk of the recession resistant silicon containing article.

First claim

1 . A recession resistant silicon containing article, comprising:
a. a silicon-containing substrate having a first coefficient of thermal expansion; and b. a bond coat comprising a two phase layer of interconnected silicon and interconnected oxide, followed by a layer of silicon,
wherein the bond coat is located on top of the substrate to form the recession resistant silicon containing article.

2 . The recession resistant silicon containing article of claim 1 , wherein the silicon containing ceramic is selected from the group consisting of silicon nitride, silicon carbide, silicon oxinitride, a metal silicide, a ceramic matrix composite material, and combinations thereof.

3 . The recession resistant silicon containing article of claim 1 , wherein the substrate comprises a SiC—SiC ceramic matrix composite.

4 . The recession resistant silicon containing article of claim 1 , wherein the oxide has an expansion coefficient of about 5 ppm per degree C.; wherein the oxide is chemically stable in moisture containing environments and/or exhibits no more than about 30% negative volume change associated with reaction with water vapor; and wherein the oxide is chemically stable with silicon oxide.

5 . The recession resistant silicon containing article of claim 1 , wherein the oxide is a Rare Earth Disilicate (RE 2 Si 2 O 7 ) with an oxide of an element chosen from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

6 . The recession resistant silicon containing article of claim 1 , where the oxide is a Rare Earth Disilicate with an oxide of the element Y and/or Yb and/or Lu.

7 . The recession resistant silicon containing article of claim 1 , wherein the oxide is hafnium oxide.

8 . The recession resistant silicon containing article of claim 1 , wherein the oxide is an Alkaline Earth Aluminosilicate comprising Alkaline Earth Silicate of one or more of the elements of Ba Sr, Ca, and Mg.

9 . The recession resistant silicon containing article of claim 1 , further comprising a protective porous oxide layer formed in-situ after the outer oxide layer of the EBC spalls during operation of the gas turbine engine component.

10 . The recession resistant silicon containing article of claim 1 , further comprising volatization of silicon from the silicon containing article, such that the rate of recession of the underlying substrate drops by a factor of between 5 and 100 when compared to control recession rates after at least a portion of the outer oxide layers of the EBC spall off.

11 . The recession resistant silicon containing article of claim 1 , wherein the layer of interconnected silicon and an oxide has a second coefficient of thermal expansion, and wherein the difference in value between the first and second coefficient of thermal expansion is no more than about 20%.

12 . The recession resistant silicon containing article of claim 1 , wherein the article further comprises a silicon layer located between the substrate and the two phase layer.

13 . The recession resistant silicon containing article of claim 1 , wherein the substrate is a ceramic matrix composite, and the bond coat comprises a layer of silicon, followed by a layer of about 5% to 50% of interconnected silicon and about 50% to 95% oxide, followed by a layer of silicon.

14 . The recession resistant silicon containing article of claim 13 , wherein the first layer of silicon is up to about 10 mils thick, the second layer is from about 2 mils to about 20 mils thick, and the third layer is from about 2 mils to about 10 mils thick.

15 . The recession resistant silicon containing article of claim 1 , wherein the structure of the interconnected silicon and interconnected oxide is in the form of vertical arrays, lattice arrays, or parallel arrays; wherein in the vertical arrays, the interconnected silicon and interconnected oxide are vertical arrays roughly normal to the surface of the substrate; wherein in the lattice arrays, the interconnected silicon and interconnected oxide are in the form of a lattice or grid relative to the surface of the substrate; and wherein in the parallel arrays, the interconnected silicon and interconnected oxide are parallel to each other relative to the surface of the substrate.

16 . The recession resistant article of claim 15 , wherein the silicon is deposited by a CVD process.

17 . The recession resistant article of claim 15 , wherein the oxide is deposited by a plasma spraying process or a slurry coating process.

18 . The recession resistant silicon containing article of claim 1 , wherein the article comprises a component of a gas turbine assembly.

19 . The recession resistant silicon containing article of claim 1 , wherein the article is a gas turbine engine component selected from the group consisting of combustor components, turbine blades, shrouds, nozzles, heat shields and vanes.

20 . A recession resistant article for a gas turbine engine, said article comprising:
a. a substrate material comprising silicon, wherein said substrate material has a first coefficient of thermal expansion; b. a silicon bondcoat bonded to at least a portion of an outer surface of said substrate material; c. an interconnected silicon and an oxide layer positioned between the substrate material and the silicon bondcoat, wherein said interconnected silicon and oxide layer has as second coefficient of thermal expansion,
wherein there is about 20% or less difference between the value of the first and second coefficients of thermal expansion.

21 . The recession resistant article of claim 20 , wherein the silicon containing ceramic is selected from the group consisting of silicon nitride, silicon carbide, silicon oxinitride, a metal silicide, a ceramic matrix composite material, and combinations thereof.

22 . The recession resistant article of claim 20 , wherein the substrate comprises a SiC—SiC ceramic matrix composite material.

23 . The recession resistant article of claim 20 , wherein the oxide has an expansion coefficient of about 5 ppm per degree C.; wherein the oxide is chemically stable in moisture containing environments and/or exhibits no more than about 30% negative volume change associated with reaction with water vapor; and wherein the oxide is chemically stable with silicon oxide.

24 . The recession resistant article of claim 20 , wherein the oxide is a Rare Earth Disilicate (RE 2 Si 2 O 7 ) with an oxide of an element chosen from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

25 . The recession resistant article of claim 20 , where the oxide is a Rare Earth Disilicate with an oxide of the element Y and/or Yb.

26 . The recession resistant article of claim 20 , wherein the oxide is hafnium oxide.

27 . The recession resistant article of claim 20 , the oxide is an Alkaline Earth Aluminosilicate comprising Alkaline Earth Silicate of one or more of the elements of Ba Sr, Ca, and Mg.

28 . The recession resistant article of claim 20 , further comprising a protective porous oxide layer formed in-situ after the outer oxide layer of the coating spalls during operation of the gas turbine engine article.

29 . The recession resistant article of claim 20 , further comprising volatization of silicon from the silicon containing article, such that the rate of recession of th

Assignees

• Gen Electric
• Gen Electric

Inventors

• Luthra Krishan Lal

Classifications

• F01D5/284 Primary

  Selection of ceramic materials · CPC title

• C23C4/134

  Plasma spraying · CPC title

• C23C16/44

  characterised by the method of coating (C23C16/04 takes precedence) · CPC title

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title

• C04B41/89

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