Ceramic compositions useful for thermal barrier coatings having reduced thermal conductivity

• US 20050142392A1
• Filed: 12/30/2003
• Published: 06/30/2005
• Est. Priority Date: 12/30/2003
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Spitsberg, Irene, Boutwell, Brett Allen, Gorman, Mark Daniel, Venkataramani, Venkat Subramanian
• Granted Patent: US 6,960,395 B2
• Time in Patent Office: Days
• US Class Current: 428/701
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3244 Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/9607 Thermal properties, e.g. thermal expansion coefficient
• CPC Class Codes: C04B 35/486 Fine ceramics
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 28/321 with at least one metal alloy layer
• CPC Class Codes: C23C 28/3215 at least one MCrAlX layer
• CPC Class Codes: C23C 28/3455 with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: F05D 2230/90 Coating; Surface treatment manufacture with deposition of material F05D2230/30
• CPC Class Codes: F05D 2300/2116 Zinc oxide
• CPC Class Codes: F05D 2300/611 Coating
• CPC Class Codes: Y10T 428/12611 Oxide-containing component
• CPC Class Codes: Y10T 428/12618 Plural oxides
• CPC Class Codes: Y10T 428/26 : Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/265 : 1 mil or less

Abstract

Ceramic compositions comprising at least about 91 mole % zirconia and up to about 9 mole % of a stabilizer component comprising a first metal oxide having selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof. This stabilizer component further comprises a second metal oxide of a trivalent metal atom selected from the group consisting of lanthana, gadolinia, neodymia, samaria, dysprosium, and mixtures thereof and a third metal oxide of a trivalent metal atom selected from the group consisting of erbia, ytterbia and mixtures thereof. These ceramic compositions are useful in preparing thermal barrier coatings having reduced thermal conductivity for the metal substrate of articles that operate at, or are exposed to, high temperatures.

Claims

1. A ceramic compositions, which comprises:

1. at least about 91 mole % zirconia; and

2. a stabilizing amount up to about 9 mole % of a stabilizer component comprising;

a. a first metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof;

b. a second metal oxide of a trivalent metal atom selected from the group consisting of lanthana, and mixtures of lanthana with gadolinia, neodymia, samaria, or dysprosia; and

c. a third metal oxide of a trivalent metal atom selected from the group consisting of ytterbia, erbia and mixtures thereof.

2. The composition of claim 1 which comprises from about 92 to about 95 mole % zirconia and from about 5 to about 8 mole % stabilizing component.

3. The composition of claim 2 wherein the first metal oxide is yttria in amount of from about 3 to about 5 mole %, wherein the second metal oxide is selected from the group consisting of lanthana, and mixtures of lanthana and gadolinia in an amount of from about 0.25 to about 2 mole % and wherein the third metal oxide is in an amount of from about 0.5 to about 2 mole %.

4. The composition of claim 3 which comprises the second and third metal oxides in a ratio of the amount of the second metal oxide to the third metal oxide of from about 0.75 to about 1.33.

5. The composition of claim 3 wherein the second metal oxide is lanthana and the third metal oxide is ytterbia.

6. A thermally protected article, which comprises:

A. a metal substrate; and

B. a thermal barrier coating comprising;

1. at least about 91 mole % zirconia; and

2. a stabilizing amount up to about 9 mole % of a stabilizer component comprising;

a. a first metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof;

b. a second metal oxide of a trivalent metal atom selected from the group consisting of lanthana, and mixtures of lanthana with gadolinia, neodymia, samaria, or dysprosia; and

c. a third metal oxide of a trivalent metal atom selected from the group consisting of ytterbia, erbia and mixtures thereof.

7. The article of claim 7 which further comprises a bond coat layer adjacent to and overlaying the metal substrate and wherein the thermal barrier coating is adjacent to and overlies the bond coat layer.

8. The article of claim 7 wherein the thermal barrier coating has a thickness of from about 1 to about 100 mils.

9. The article of claim 8 wherein the thermal barrier coating has a strain-tolerant columnar structure.

10. The article of claim 9 wherein the thermal barrier coating comprises from about 92 to about 95 mole % zirconia and from about 5 to about 8 mole % total stabilizing component.

11. The article of claim 9 wherein the first metal oxide is yttria in amount of from about 3 to about 5 mole % of the thermal barrier coating, wherein the second metal oxide is selected from the group consisting of lanthana, and mixtures of lanthana and gadolinia in an amount of from about 0.5 to about 2 mole % of the thermal barrier coating and wherein the third metal oxide is in an amount of from about 0.5 to about 2.0 mole % of the thermal barrier coating.

12. The article of claim 11 wherein the thermal barrier coating comprises the second and third metal oxides in a ratio of the amount of the second metal oxide to the third metal oxide of from about 0.75 to about 1.33.

13. The article of claim 15 wherein the second metal oxide is lanthana and the third metal oxide is ytterbia.

14. The article of claim 9 which is a turbine engine component.

15. The article of claim 14 which is a turbine shroud and wherein the thermal barrier coating has a thickness of from about 30 to about 70 mils.

16. The article of claim 14 which is a turbine airfoil and wherein the thermal barrier coating has a thickness of from about 3 to about 15 mils.

17. A method for preparing a thermal barrier coating on an underlying metal substrate, the method comprising the step of:

A. forming a thermal barrier coating over the metal substrate by depositing a ceramic composition, which comprises;

1. at least about 91 mole % zirconia; and

2. a stabilizing amount up to about 9 mole % of a stabilizer component comprising;

a. a first metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof; and

b. a second metal oxide of a trivalent metal atom selected from the group consisting of lanthana, and mixtures of lanthana with gadolinia, neodymia, samaria, or dysprosia; and

c. a third metal oxide of a trivalent metal atom selected from the group consisting of ytterbia, erbia and mixtures thereof.

18. The method of claim 17 wherein a bond coat layer is adjacent to and overlies the metal substrate and wherein the thermal barrier coating is formed on the bond coat layer.

19. The method of claim 18 wherein the ceramic composition is deposited by physical vapor deposition to form a thermal barrier coating having a strain-tolerant columnar structure.

20. The method of claim 19 wherein the ceramic composition that is deposited comprises from about 92 to about 95 mole % zirconia and from about 5 to about 8 mole % total stabilizing component.

21. The method of claim 20 wherein the ceramic composition that is deposited comprises yttria as the first metal oxide in amount of from about 3 to about 5 mole %, a second metal oxide is selected from the group consisting of lanthana, and mixtures of lanthana and gadolinia in an amount of from about 0.25 to about 2 mole % and a third metal oxide is in an amount of from about 0.5 to about 2 mole %.

22. The method of claim 21 wherein the ceramic composition that is deposited comprises the second and third metal oxides in a ratio of the amount of the second metal oxide to the third metal oxide of from about 0.75 to about 1.33.

23. The method of claim 22 wherein the ceramic composition that is deposited comprises lanthana as the second metal oxide and ytterbia as the third metal oxide.