Environmental barrier for a substrate comprising free silicon

Patent metadata

Field	Value
Publication number	US-12312282-B2
Application number	US-202218576024-A
Country	US
Kind code	B2
Filing date	Jun 30, 2022
Priority date	Jul 7, 2021
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

A part includes a substrate of ceramic matrix composite material, the substrate including silicon, the part further including an environmental barrier formed on at least one surface of the substrate, wherein the environmental barrier includes at least one compound selected from Yb2-2γGd2γSiO5 and Yb2-2γGd2γSi2O7, where γ is between 0.05 and 0.15, and wherein the environmental barrier further includes alumina Al2O3, the molar alumina content being between 5% and 15% of the total environmental barrier composition.

First claim

The invention claimed is:

1. A part comprising a substrate of ceramic matrix composite material, the substrate comprising silicon, the part further comprising an environmental barrier formed on at least one surface of the substrate,
wherein the environmental barrier comprises at least one compound selected from Yb 2-2γ Gd 2γ SiO 5 and Yb 2-2γ Gd 2γ Si 2 O 7 , where γ is between 0.05 and 0.15,
and wherein the environmental barrier further comprises alumina Al 2 O 3 , a molar alumina content being between 5% and 15% relative to a total environmental barrier composition.

2. The part according to claim 1 , further comprising a bonding layer comprising silicon present between the surface of the substrate and the environmental barrier.

3. The part according to claim 1 , wherein the substrate is a composite material part whose matrix comprises silicon carbide.

4. The part according to claim 1 , wherein the environmental barrier jointly comprises the compounds Yb 2-2γ Gd 2γ SiO 5 , Yb 2-2γ Gd 2γ Si 2 O 7 , where γ is between 0.05 and 0.15.

5. The part according to claim 1 , wherein the environmental barrier comprises only one of the compounds selected from Yb 2-2γ Gd 2γ SiO 5 , Yb 2-2γ Gd 2γ Si 2 O 7 where γ is between 0.05 and 0.15.

6. The part according to claim 1 , wherein the environmental barrier has a densification rate greater than or equal to 98%.

7. A method for protecting a substrate, a portion of which adjacent to a surface is made of a material comprising silicon, during high-temperature use in an oxidizing and humid environment, the method comprising forming an environmental barrier on the surface of the substrate,
wherein the environmental barrier comprises at least one compound selected from Yb 2-2γ Gd 2γ SiO 5 , Yb 2-2γ Gd 2γ Si 2 O 7 where γ is between 0.05 and 0.15, and alumina (Al 2 O 3 ) in a molar content of between 5% and 15% relative to a total environmental barrier composition, the environmental barrier maintaining a majority solid phase up to at least 1400° C. and presenting a liquid phase at a temperature higher than or equal to 1300° C., so that a quantity of liquid phase ensures the self-healing capacity of the barrier for a temperature of use higher than or equal to 1300° C.

8. The method of claim 7 , wherein forming the environmental barrier comprises a sintering step of ytterbium oxide powder (Yb 2 O 3 ), gadolinium oxide powder (Gd 2 O 3 ), an alumina powder (Al 2 O 3 ) and a silica powder (SiO 2 ) at a temperature between 1300° C. and 1400° C.

9. The method according to claim 7 , further comprising a step for obtaining a bonding layer comprising silicon on the surface of the substrate, prior to forming the environmental barrier.

10. The part according to claim 1 , wherein the environmental barrier layer has a composition lying, in the Yb 2 O 3 —Al 2 O 3 —SiO 2 ternary diagram, on an isopleth from ytterbium disilicate to mullite, with some of the ytterbium being substituted by gadolinium.

11. The part according to claim 1 , wherein a composition of the environmental barrier is selected such that the environmental barrier maintains a majority of solid phase up to at least 1400° C. and presents a liquid phase at a temperature higher than or equal to 1300° C., so that a quantity of liquid phase ensures self-healing capacity of the environmental barrier for a temperature of use higher than or equal to 1300° C.

12. The part according to claim 11 , wherein an amount of liquid phase is between 5% and 40% by mass relative to a total mass of the environmental barrier for a temperature between 1350° C. and 1400° C.

Assignees

• Safran Ceram
• Univ Bordeaux
• Centre Nat Rech Scient

Inventors

• Mouret Thibault
• Rebillat Francis
• Maille Laurence
• Arnal Simon
• Bouillon Eric

Classifications

• C04B2235/428

  Silicon · CPC title

• C04B2235/3826

  Silicon carbides · CPC title

• C04B2235/3418

  Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint · CPC title

• C04B2235/3224

  Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide · CPC title

• C04B2235/3217

  Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina · CPC title