PART COMPRISING A SUBSTRATE AND AN ENVIRONMENTAL BARRIER

• US 20190330121A1
• Filed: 01/04/2018
• Published: 10/31/2019
• Est. Priority Date: 01/06/2017
• Status: Active Grant

• Current Assignee: Centre National De La Recherche Scientifique, Safran Ceramics, Université de Bordeaux
• Original Assignee: Centre National De La Recherche Scientifique, Safran Ceramics, Université de Bordeaux
• Inventors: PIN, Lisa, ARNAL, Simon, REBILLAT, Francis, MAUVY, Fabrice
• Granted Patent: US 11,713,283 B2
• Time in Patent Office: Days
• CPC Class Codes: C04B 2103/0021 Compounds of elements having a valency of 3
• 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 41/0009 Demolition agents based on cementitous or like materials
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4527 Plasma spraying deposition from the gas phase using plasma C04B41/4533
• CPC Class Codes: C04B 41/5024 Silicates C04B41/5022 takes precedence; silico-fluorides C04B41/5018
• CPC Class Codes: C04B 41/5045 Rare-earth oxides
• 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 41/526 Multiple coating or impregnation with materials having the same composition but different characteristics
• 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 5/284 Selection of ceramic materials
• CPC Class Codes: F01D 5/288 Protective coatings for blades

Abstract

A part includes a substrate, having, adjacent to a surface of the substrate, at least a portion that is made from a material that contains silicon, and an environmental barrier formed on the surface of the substrate, the environmental barrier including at least a first layer including a rare earth disilicate of formula RE^a₂Si₂O₇ present at a molar content lying in the range 70% to 99.9%, where RE^a is a rare earth element; and at least one rare earth oxide of formula RE^b₂O₃ present at a molar content lying in the range 0.1% to 30%, where RE^b is a rare earth element different from RE^a.

Claims

1. A part comprising a substrate, having, adjacent to a surface of the substrate, at least a portion that is made from a material that contains silicon, and an environmental barrier formed on the surface of the substrate, the environmental barrier comprising at least a first layer comprising:

a rare earth disilicate of formula RE^a₂Si₂O₇ present at a molar content lying in the range 70% to 99.9%, where RE^a is a rare earth element; and

at least one rare earth oxide of formula RE^b₂O₃ present at a molar content lying in the range 0.1% to 30%, where RE^b is a rare earth element different from RE^a.

2. A part according to claim 1, wherein RE^b is selected from terbium Tb, erbium Er, dysprosium Dy, gadolinium Gd, europium Eu, lutetium Lu, samarium Sm, yttrium Y, and ytterbium Yb.

3. A part according to claim 2, wherein RE^b is selected from terbium Tb, erbium Er, and dysprosium Dy.

4. A part according to claim 1, wherein the rare earth disilicate of formula RE^a₂Si₂O₇ is present in the first layer at a molar content lying in the range 80% to 95%, and wherein said at least one rare earth oxide of formula RE^b₂O₃ is present in the first layer at a molar content lying in the range 5% to 20%.

5. A part according to claim 1, wherein RE^a is selected from yttrium Y and ytterbium Yb.

6. A part according to claim 1, wherein the environmental barrier further comprises a second layer present on the first layer, the second layer comprising at least one rare earth monosilicate of formula RE^c₂SiO₅, where RE^c is a rare earth element.

7. A part according to claim 6, wherein the second layer comprises at least:

the rare earth monosilicate of formula RE^c₂SiO₅ at a molar content lying in the range 85% to 99.9%; and

at least one rare earth oxide of formula RE^d₂O₃ present at a molar content lying in the range 0.1% to 15%, where RE^d is a rare earth element different from RE^c.

8. A part according to claim 7, wherein RE^d is selected from terbium Tb, erbium Er, dysprosium Dy, gadolinium Gd, europium Eu, lutetium Lu, samarium Sm, yttrium Y, and ytterbium Yb.

9. A part according to claim 8, wherein RE^d is selected from terbium Tb, erbium Er, and dysprosium Dy.

10. A part according to claim 7, wherein the rare earth monosilicate of formula RE^c₂SiO₅ is present in the second layer at a molar content lying in the range 85% to 95%, and wherein said at least one rare earth oxide of formula RE^d₂O₃ is present in the second layer at a molar content lying in the range 5% to 15%.

11. A part according to claims 6, wherein RE^c is selected from yttrium Y and ytterbium Yb.

12. A part according to claim 7, wherein RE^a is yttrium Y, RE^c is ytterbium Yb, and RE^b and RE^d are independent of each other, and selected from terbium Tb, erbium Er, and dysprosium Dy.

13. A part according claim 6, wherein the environmental barrier further comprises a third layer present between the first layer and the second layer, the third layer comprising:

the rare earth disilicate of formula RE^a₂Si₂O₇ at a molar content equal to A·

Ta, where Ta is the molar content of RE^a₂Si₂O₇ in the first layer;

said at least one rare earth oxide of formula RE^b₂O₃ at a molar content equal to A.·

Tb, where Tb is the molar content of RE^b₂O₃ in the first layer; and

the rare earth monosilicate of formula RE^c₂SiO₅ at a molar content equal to (1−

A)·

Tc, where Tc is the molar content of RE^c₂SiO₅ in the second layer;

where A designates a weighting coefficient that is strictly greater than 0 and strictly less than 1.

14. A method of fabricating a part according to claim 1, comprising forming the first layer of the environmental barrier on the surface of the substrate.

15. A method of using a part according to claim 1, comprising using said part at a temperature higher than or equal to 800°

C. in a medium that is oxidizing and wet.