Silicon based substrate with environmental/thermal barrier layer

• US 6,589,677 B1
• Filed: 12/19/2001
• Issued: 07/08/2003
• Est. Priority Date: 12/19/2001
• Status: Expired due to Term

• Current Assignee: Raytheon Technologies Corporation d/b/a RTX (Rtx Corporation)
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Sun, Ellen Y., Eaton, Harry E.
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): MCNEIL, JENNIFER C
• Application Number:
  US10/033,955
• Publication Number:
  US 20030113552A1
• Time in Patent Office: 566 Days
• Field of Search: 428/408, 428/469, 428/697, 428/698, 428/699, 428/701, 428/702, 428/446, 428/448, 428/660, 428/680, 428/681, 416/241.B, 416/241.R
• US Class Current: 428/698
• CPC Class Codes: C04B 35/565 based on silicon carbide
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/597 based on silicon oxynitride, e.g. SIALONS
• CPC Class Codes: C04B 35/806 The matrix of the ceramic products consisting of non-oxides only
• 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 41/5027 Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051
• CPC Class Codes: C04B 41/5051 Niobium oxides or niobates
• CPC Class Codes: C04B 41/87 Ceramics
• CPC Class Codes: C23C 28/042 including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides
• CPC Class Codes: C23C 28/048 with layers graded in composition or physical properties
• 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: C23C 4/11 Oxides
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: F05D 2300/222 Silicon
• CPC Class Codes: Y10T 428/12806 Refractory [Group IVB, VB, or VIB] metal-base component
• CPC Class Codes: Y10T 428/12944 Ni-base component
• CPC Class Codes: Y10T 428/12951 Fe-base component
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

An article comprising a substrate containing silicon and at least one barrier layer which functions as a thermal barrier at temperatures in excess of 1300° C. in aqueous environments.

Claims

1. An article comprising:

a substrate comprising silicon; and

at least one barrier layer, wherein the at least one thermal barrier layer comprises TaO_x, where x=1 to 3, and an oxide selected from the group consisting of MgO, CaO, SrO, BaO, Al₂O₃, Y₂O₃, La₂O₃, Re₂O₃ (where Re is a rare earth element) and mixtures thereof in an amount sufficient to reduce the rate of weight loss and recession of the substrate at temperatures in excess of 1300°

C. in aqueous environments where compared to the at least one barrier layer without the additive.

2. An article according to claim 1 wherein the substrate is selected from the group consisting of silicon containing ceramic and metal alloys containing silicon.

3. An article according to claim 2 wherein the substrate is a silicon containing ceramic selected from the group consisting of silicon carbide, silicon nitride, and silicon aluminum oxynitride.

4. An article according to claim 2 wherein the substrate is a composite comprising a silicon based matrix and a reinforcing particle.

5. An article according to claim 4 wherein said substrate is selected from the group consisting of silicon carbide fiber-reinforced silicon carbide matrix, carbon fiber-reinforced silicon carbide matrix and silicon carbide fiber-reinforced silicon nitride.

6. An article according to claim 2 wherein said substrate is a silicon containing metal alloy selected from the group consisting of molybdenum-silicon alloys, niobium silicon alloys, iron-silicon alloys, and iron-nickel-silicon based alloys.

7. An article according to claim 6 wherein said barrier layer comprises between 10 to 50 wt. % of TaO_x, balance said oxide.

8. An article according to claim 7 wherein the barrier layer further comprises a CTE tailoring additive.

9. An article according to claim 8 wherein the CTE tailoring additive is NbO_x, where x=1 to 3.

10. An article according to claim 2 wherein said barrier layer comprises up to 75 wt. % of TaO_x, balance, essentially said oxide.

11. An article according to claim 10 wherein the barrier layer further comprises a CTE tailoring additive.

12. An article according to claim 11 wherein the CTE tailoring additive is NbO_x, where x=1 to 3.

13. An article according to claim 1 including an intermediate layer between the substrate and the barrier layer.

14. An article according to claim 13 wherein the intermediate layer contains a CTE tailoring additive.

15. An article according to claim 14 wherein the CTE tailoring additive is NbO_x, where x=1 to 3.

16. An article according to claim 13 wherein the coefficient of thermal expansion of the intermediate layer is within ±

3.0 ppm/°

C. the coefficient of thermal expansion of the substrate and the barrier layer.

17. An article according to claim 13 wherein the coefficient of thermal expansion of the intermediate layer is within ±

0.5 ppm/°

C. the coefficient of thermal expansion of the substrate and the barrier layer.

18. An article according to claim 1 wherein the coefficient of thermal expansion of the barrier layer is within ±

3.0 ppm/°

C. the coefficient of thermal expansion of the substrate.

19. An article according to claim 1 wherein the coefficient of thermal expansion of the barrier layer is within ±

0.5 ppm/°

C. the coefficient of thermal expansion of the substrate.

20. An article according to claim 1, wherein the thermal barrier additive is present in an amount sufficient to reduce the rate of weight loss and recession at temperatures between 1350°

C. and 1450°

C.