Thermal barrier coating with controlled defect architecture

Patent metadata

Field	Value
Publication number	US-9850778-B2
Application number	US-201314082661-A
Country	US
Kind code	B2
Filing date	Nov 18, 2013
Priority date	Nov 18, 2013
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Yttria stabilized zirconia (YSZ) particles ( 40 ) form a thermal barrier layer ( 58 ) on a metal substrate ( 24 ). The YSZ particles have a porous interior ( 52, 54 ) and a fully melted and solidified outer shell ( 50 ). The thermal barrier layer may have porosity greater than 12%, including porosity within the particles and inter-particle gap porosity. Inter-particle gaps may be greater than 5 microns. The thermal barrier layer may exhibit elastic hysteresis and an average modulus of elasticity of 15-25 GPa. A bond coat ( 44 A, 44 B) may be applied between the substrate and the thermal barrier layer. The bond coat may have a first dense MCrAlY layer ( 44 A) on the substrate and a second rough, porous MCrAlY layer ( 44 B) on the first MCrAlY layer, the bond layers diffusion bonded to each other and to the substrate.

First claim

The invention claimed is:

1. A thermal barrier coating system comprising:
a bond coat on a substrate;
a plurality of ceramic particles forming a thermal barrier layer on the bond coat, wherein the ceramic particles comprise a porous interior portion and a non-porous outer shell;
wherein the outer shell of at least most of the particles in the thermal barrier layer comprises 10-50% by volume of the particle; wherein the thermal barrier layer exhibits elastic hysteresis on a stress/strain graph with linear/linear units, wherein first and second stress/strain curves each span between a beginning point on the graph and an ending point on the graph, forming a hysteresis loop, and wherein a distance between the two stress/strain curves divided by a distance between the beginning and ending points gives a hysteresis magnitude in a range of 0.05-0.10, wherein the distance between the two stress/strain curves is taken along a perpendicular drawn from a midpoint of a line between the beginning and ending points.

2. The thermal barrier coating of claim 1 , wherein in at least 80% of the particles the outer shell comprises 10-50% by volume of the particle.

3. The thermal barrier coating of claim 1 , wherein in at least 80% of the particles the outer shell comprises 10-25% by volume of the particle, and have an aspect ratio in a range of 1-4.

4. The thermal barrier coating of claim 1 , wherein the thermal barrier layer has a porosity greater than 12%, including a porosity within the particles of the plurality and an inter-particle porosity in the thermal barrier layer.

5. The thermal barrier coating system of claim 1 , wherein the thermal barrier layer exhibits elastic hysteresis and an average modulus of elasticity of 15-25 GPa.

6. The thermal barrier coating system of claim 1 , wherein the thermal barrier layer comprises an average inter-particle gap width of greater than 5 microns.

7. The thermal barrier coating system of claim 1 , wherein the bond coat comprises a first MCrAlY layer on the substrate, and a second MCrAlY layer on the first MCrAlY layer, wherein the second MCrAlY layer has a lower density and a higher roughness than the first MCrAlY layer, and the first and second MCrAlY layers are diffusion bonded to each other and to the substrate.

8. A thermal barrier coating system comprising:
a plurality of yttria stabilized zirconia (YSZ) particles forming a thermal barrier layer on a substrate, wherein at least 80% of the YSZ particles comprise a porous interior portion and a fully melted and solidified outer shell;
wherein for said at least 80% of the particles, the outer shell comprises 10-50% by volume of the particle, and an average particle has an aspect ratio in a range of 1-4;
wherein the thermal barrier layer has a porosity greater than 12%, including a porosity within the particles thereof and an inter-particle porosity thereof; and
wherein the thermal barrier layer exhibits elastic hysteresis over an average modulus of elasticity of 15-25 GPa.

9. The thermal barrier coating system of claim 8 , further comprising a bond coat between the substrate and the thermal barrier layer, wherein the bond coat comprises a first MCrAlY layer on the substrate, and a second MCrAlY layer on the first MCrAlY layer, wherein the second MCrAlY layer has a lower density and a higher surface roughness than the first MCrAlY layer, and the first and second MCrAlY layers are diffusion bonded to each other and to the substrate.

10. The thermal barrier coating system of claim 8 , wherein the thermal barrier layer comprises elastic hysteresis over a given stress range, and comprises an average modulus of elasticity of 16-20 GPa over the given stress range.

11. The thermal barrier coating system of claim 8 , wherein the thermal barrier layer comprises an average inter-particle gap width of 20-30 microns.

12. The thermal barrier coating of claim 8 wherein the thermal barrier layer exhibits elastic hysteresis on a stress/strain graph with linear/linear units, wherein first and second stress/strain curves each span between a beginning point on the graph and an ending point on the graph, forming a hysteresis loop, and wherein a distance between the two stress/strain curves divided by a distance between the beginning and ending points gives a hysteresis magnitude in a range of 0.05-0.10, wherein the distance between the two stress/strain curves is taken along a perpendicular drawn from a midpoint of a line between the beginning and ending point.

13. The thermal barrier coating system of claim 8 , wherein the thermal barrier layer comprises a porosity of 15-17%, including a porosity within the particles thereof and an inter-particle gap porosity thereof.

14. A thermal barrier coating system comprising:
a plurality of ceramic particles forming a thermal barrier layer on a metal substrate, wherein at least 80% of the particles comprise a porous interior portion with less than 90% of theoretical density and a non-porous outer shell with greater than 95% of theoretical density;
wherein for said at least 80% of the particles, the outer shell comprises 10-25% by volume of the particle, and an average particle has an aspect ratio in a range of 1-4;
wherein the thermal barrier layer has a porosity greater than 12%, including a porosity within the particles thereof and an inter-particle gap porosity thereof; and
wherein the thermal barrier layer exhibits elastic hysteresis over a given stress range and average modulus of elasticity of 15-25 GPa over the given stress range.

15. The thermal barrier coating system of claim 14 , further comprising a bond coat between the substrate and the thermal barrier layer, wherein the bond coat comprises a first MCrAlY layer on the substrate, and a second MCrAlY layer on the first MCrAlY layer, wherein the second MCrAlY layer has a lower density and a higher surface roughness than the first MCrAlY layer, and the first and second MCrAlY layers are diffusion bonded to each other and to the substrate.

16. The thermal barrier coating system of claim 14 , wherein the thermal barrier layer exhibits an elastic hysteresis over a given stress range, and an average modulus of elasticity of 16-20 GPa over the given stress range.

17. The thermal barrier coating system of claim 14 , wherein the thermal barrier layer comprises an average inter-particle gap width of 20-30 microns.

18. The thermal barrier coating of claim 14 wherein the thermal barrier layer exhibits an elastic hysteresis on a stress/strain graph with linear/linear units, wherein first and second stress/strain curves each span between a beginning point on the graph and an ending point on the graph, forming a hysteresis loop, and wherein a distance between the two stress/strain curves divided by a distance between the beginning and ending points gives a hysteresis magnitude in a range of 0.05-0.10, wherein the distance between the two stress/strain curves is taken along a perpendicular drawn from a midpoint of a line between the beginning and ending points.

19. The thermal barrier coating system of claim 14 , wherein the thermal barrier layer comprises a porosity of 15-17%, including a porosity within the particles thereof and an inter-particle porosity thereof.

Assignees

• Riggs Walter L
• Swanson Gunnar W
• Lammers Heiko
• Siemens Energy Inc

Inventors

• Riggs Walter L
• Swanson Gunnar W
• Lammers Heiko

Classifications

• F01D25/005 Primary

  Selecting particular materials · CPC title

• C23C28/3215 Primary

  at least one MCrAlX layer · CPC title

• C23C4/073

  containing MCrAl or MCrAlY alloys, where M is nickel, cobalt or iron, with or without non-metal elements · CPC title

• F01D5/288

  Protective coatings for blades · CPC title

• C23C28/3455

  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 title