Ceramic compositions useful for thermal barrier coatings having reduced thermal conductivity

• US 6,960,395 B2
• Filed: 12/30/2003
• Issued: 11/01/2005
• Est. Priority Date: 12/30/2003
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Spitsberg, Irene, Boutwell, Brett Allen, Gorman, Mark Daniel, Venkataramani, Venkat Subramanian
• Primary Examiner(s): MCNEIL, JENNIFER C
• Application Number:
  US10/748,508
• Publication Number:
  US 20050142392A1
• Time in Patent Office: 672 Days
• Field of Search: 428/632, 428/633, 428/697, 428/699, 428/701, 428/702, 428/336, 501/103, 501/104, 501/105, 252/62, 427/453, 427/585, 427/584, 427/250, 427/421, 416/241.B
• US Class Current: 428/632
• 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 composition, which comprises:

1. from about 92 to about 95 mole % zirconia; and

2. from about 5 to about 8 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 in amount of from about 3 to about 5 mole %;

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, in an amount of from about 0.25 to about 2 mole %; and

c. ytterbia in an amount of from about 0.5 to about 2 mole %.

2. The composition of claim 1 which comprises the second metal oxide and ytterbia in a ratio of the amount of the second metal oxide to ytterbia of from about 0.75 to about 1.33.

3. The composition of claim 1 wherein the second metal oxide is lanthana.

4. A thermally protected article, which comprises:

A. a metal substrate; and

A. a thermal barrier coating comprising;

1. from about 92 to about 95 mole % zirconia; and

2. from about 5 to about 8 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 in amount of from about 3 to about 5 mole %;

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, in an amount of from about 0.25 to about 2 mole %; and

c. ytterbia in an amount of from about 0.5 to about 2 mole %.

5. The article of claim 4 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.

6. The article of claim 5 wherein the thermal barrier coating has a thickness of from about 1 to 100 mils.

7. The article of claim 6 wherein the thermal barrier coating has a strain-tolerant columnar structure.

8. The article of claim 7 which is a turbine engine component.

9. The article of claim 8 which is a turbine shroud and wherein the thermal barrier coating has a thickness of from about 30 to about 70 mils.

10. The article of claim 8 which is a turbine airfoil and wherein the thermal barrier coating has a thickness of from about 3 to about 15 mils.

11. The article of claim 4 wherein the thermal barrier coating comprises the second metal oxide and ytterbia in a ratio of the amount of the second metal oxide ytterbia of from about 0.75 to about 1.33.

12. The article of claim 4 wherein the second metal oxide is lanthana.

13. 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. from about 92 to about 95 mole % zirconia; and

2. from about 5 to about 8 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 in amount of from about 3 to about 5 mole %; 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, in an amount of from about 0.25 to about 2 mole %; and

c. ytterbia in an amount of from about 0.5 to about 2 mole %.

14. The method of claim 13 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.

15. The method of claim 14 wherein the ceramic composition is deposited by physical vapor deposition to form a thermal barrier coating having a strain-tolerant columnar structure.

16. The method of claim 13 wherein the ceramic composition that is deposited comprises the second metal oxide and ytterbia in a ratio of the amount of the second metal oxide to ytterbia of from about 0.75 to about 1.33.

17. The method of claim 16 wherein the ceramic composition that is deposited comprises lanthana as the second metal oxide.