Hot corrosion-resistant coatings and components protected therewith

Patent metadata

Field	Value
Publication number	US-9945036-B2
Application number	US-201113053378-A
Country	US
Kind code	B2
Filing date	Mar 22, 2011
Priority date	Mar 22, 2011
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A coating system on a superalloy or silicon-containing substrate of an article exposed to high temperatures. The coating system includes a coating layer that overlies the substrate and is susceptible to hot corrosion promoted by molten salt impurities. A corrosion barrier coating overlies the coating layer and contains at least one rare-earth oxide-containing compound that reacts with the molten salt impurities to form a dense, protective byproduct barrier layer.

First claim

The invention claimed is:

1. A coating system on a substrate of an article, the coating system comprising:
at least one coating layer overlying the substrate, the coating layer having a composition that is susceptible to hot corrosion promoted by molten salt impurities; and
a corrosion barrier coating overlying the coating layer and wherein the corrosion barrier coating contains at least one rare-earth oxide-containing compound that reacts with the molten salt impurities to form a dense, protective byproduct barrier layer on the surface of the corrosion barrier coating, the at least one rare-earth oxide-containing compound being present in the corrosion barrier coating in an amount of at least 15 weight percent of the corrosion barrier coating
wherein the rare-earth oxide-containing compound is comprised of a rare earth zirconate (RE 2 Zr 2 O 7 ), a rare earth hafnate (RE 2 Hf 2 O 7 ) or a mixture thereof
wherein RE in the RE 2 Zr 2 O 7 is selected from the group consisting of Sc, Ce, Pr, Pm, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu and combinations thereof and
wherein RE in the RE 2 Hf 2 O 7 is selected from the group consisting of Sc, Ce, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu and combinations thereof;

wherein the substrate comprises a silicon-containing material selected from the group consisting of metal silicide alloys, metal matrix composites reinforced with any one or more of silicon carbide, silicon nitride, a silicide and/or silicon, composites having a matrix of silicon carbide, silicon nitride, a silicide and/or silicon, and composites with a silicon carbide, silicon nitride, silicide and/or silicon matrix reinforced with silicon carbide, silicon nitride, a silicide and/or silicon.

2. The coating system according to claim 1 , further comprising at least one bondcoat between the substrate and the coating layer, the bondcoat comprising at least one of elemental silicon, silicon with one or more additional ceramic phases, and silicon alloys.

3. A coating system on a substrate of an article, the coating system comprising:
at least one coating layer overlying the substrate, the coating layer having a composition that is susceptible to hot corrosion promoted by molten salt impurities; and
a corrosion barrier coating overlying the coating layer and wherein the corrosion barrier coating contains at least one rare-earth oxide-containing compound that reacts with the molten salt impurities to form a dense, protective byproduct barrier layer on the surface of the corrosion barrier coating, the at least one rare-earth oxide-containing compound being present in the corrosion barrier coating in an amount of at least 15 weight percent of the corrosion barrier coating
wherein the rare-earth oxide-containing compound is comprised of a rare earth zirconate (RE 2 Zr 2 O 7 ), a rare earth hafnate (RE 2 Hf 2 O 7 ) or a mixture thereof
wherein RE in the RE 2 Zr 2 O 7 is selected from the group consisting of Sc, Ce, Pr, Pm, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu and combinations thereof and
wherein RE in the RE 2 Hf 2 O 7 is selected from the group consisting of Sc, Ce, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu and combinations thereof;

wherein the coating layer is an environmental barrier layer comprising silicates, alkaline-earth metal aluminosilicates and/or rare-earth metal silicates.

4. The coating system according to claim 3 , further comprising at least one thermal barrier layer between the coating layer and the corrosion barrier coating.

5. The coating system according to claim 3 , wherein the substrate comprises a metallic material selected from the group consisting of nickel-, cobalt- and iron-based superalloys.

6. The coating system according to claim 5 , further comprising at least one bondcoat between the substrate and the coating layer, the bondcoat comprising an MCrAlX overlay coating (where M is iron, cobalt and/or nickel, and X is yttrium, a rare-earth metal, and/or reactive metal) or diffusion aluminide intermetallics.

7. The coating system according to claim 5 , further comprising at least one thermal barrier layer between the coating layer and the corrosion barrier coating.

8. The coating system according to claim 3 , wherein the corrosion barrier coating further comprises a thermal-insulating material comprising any one or more of stabilised zirconia, zirconate or perovskite material.

9. The coating system according to claim 3 , wherein the corrosion barrier coating comprises, by weight, at least 30% of the at least one rare-earth oxide-containing compound.

10. The coating system according to claim 3 , wherein the corrosion barrier coating comprises, by weight, about 50% to about 100% of the at least one rare-earth oxide-containing compound.

11. The coating system according to claim 3 , further comprising a byproduct barrier layer on the surface of the corrosion barrier coating, the byproduct barrier layer defining an outermost surface layer of the coating system.

12. The coating system according to claim 3 , wherein the article comprises a component of a gas turbine engine.

13. A coating system according claim 3 wherein RE in RE 2 Zr 2 O 7 is Sc, Ce, Pr, Pm, Eu, Tb, Ho, Er, Tm, Yb, or Lu.

14. A coating system on a substrate of an article, the coating system comprising:
at least one coating layer overlying the substrate, the coating layer having a composition that is susceptible to hot corrosion promoted by molten salt impurities; and
a corrosion barrier coating overlying the coating layer and wherein the corrosion barrier coating contains at least one rare-earth oxide-containing compound that reacts with the molten salt impurities to form a dense, protective byproduct barrier layer on the surface of the corrosion barrier coating, the at least one rare-earth oxide-containing compound being present in the corrosion barrier coating in an amount of at least 15 weight percent of the corrosion barrier coating
wherein the rare-earth oxide-containing compound is comprised of a rare earth zirconate (RE 2 Zr 2 O 7 ), a rare earth hafnate (RE 2 Hf 2 O 7 ) or a mixture thereof
wherein RE in the RE 2 Zr 2 O 7 is selected from the group consisting of Sc, Ce, Pr, Pm, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu and combinations thereof and
wherein RE in the RE 2 Hf 2 O 7 is selected from the group consisting of Sc, Ce, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu and combinations thereof;

wherein the corrosion barrier coating further comprises rare-earth monosilicates (RE 2 SiO 5 ) and/or rare-earth disilicates (RE 2 Si 2 O 7 ) wherein RE in the RE 2 SiO 5 is selected from the group consisting of Sc, Ce, Pr, Pm, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu and combinations thereof and
wherein RE in the RE 2 Si 2 O 7 is selected from the group consisting of Sc, Ce, Pr, Pm, Sm, Eu, Tb, Ho, Er, Tm, Yb Lu and combinations thereof.

15. A coating system on a substrate of an article, the coating system comprising:
at least one coating layer overlying the substrate, the coating layer having a composition that is susceptible to hot corrosion promoted by molten salt impurities; and
a corrosion barrier coating overlying the coating layer and wherein the corrosion barrier coating contains at least one rare-earth oxide-containing compound that reacts with the molten salt impurities to form a dense, protective byproduct barrier layer on the surface of the corrosion barrier coating, the at least one rare-earth oxide-containing compound being present in the corrosion barrier coating in an amount of at least 15 weight percent of the corrosion barrier coating
wherein the rare-earth oxide-containing compound is comprised of a rare earth zi

Assignees

• Meschter Peter Joel
• Rowe Raymond Grant
• Gen Electric

Inventors

• Meschter Peter Joel
• Rowe Raymond Grant

Classifications

• C04B35/584

  based on silicon nitride · CPC title

• C23C28/34

  including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates · CPC title

• C04B41/522

  Multiple coatings, for one of the coatings of which at least one alternative is described · CPC title

• C04B41/5027

  Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051 · CPC title

• Y02T50/672

  Cross-Sectional Technologies · mapped topic