Articles having damage-tolerant thermal barrier coating
An article having a damage-tolerant thermal barrier coating includes a plurality of coating layers disposed over a substrate. The plurality of coatings comprises an inner layer and an outer layer. The outer layer is more resistant to infiltration by nominal CMAS relative to 8 weight percent yttria-stabilized zirconia at a temperature of 1300 degrees Celsius. The inner layer has, in a temperature range from about 1000 degrees Celsius to about 1200 degrees Celsius, a thermal resistance in a range from about 9×10 −5 degree Kelvin per watt to about 23×10 −5 degree Kelvin per watt.
1. An article comprising:
a plurality of coating layers disposed over a substrate, the plurality comprising an inner layer and an outer layer, wherein
a) the outer layer comprises yttria-stabilized zirconia with an yttria content greater than 38 weight percent and is more resistant to infiltration by nominal CMAS relative to 8weight percent yttria-stabilized zirconia at a temperature of 1300 degrees Celsius; and
b) the inner layer has, in a temperature range from about 1000 degrees Celsius to about 1200 degrees Celsius, a thermal resistance in a range from about 9 ×10 −5 degree Kelvin per watt to about 23 ×10 −5 degree Kelvin per watt, and a thickness of from about 200 to about 300 μm,
wherein a thickness of the outer layer is greater than the thickness of the inner layer.
2. The article of claim 1 , wherein the outer layer has a thickness such that the total thermal resistance of the plurality of coating layers is at least about 24 degree Kelvin per watt.
3. The article of claim 1 , wherein the inner layer comprises yttria-stabilized zirconia.
4. The article of claim 3 , wherein the yttria-stabilized zirconia has a yttria content in a range from about 6 weight percent to about 9 weight percent.
5. The article of claim 1 , wherein the inner layer comprises stabilized hafnia, stabilized titania, or combinations thereof.
6. The article of claim 1 , wherein the yttria content is at least about 55 weight percent.
7. The article of claim 1 , wherein the article comprises a turbine airfoil component or a turbine combustion component.
8. The article of claim 1 , wherein the substrate comprises a superalloy.
9. An article comprising:
a plurality of coating layers disposed over a substrate, the plurality comprising an inner layer and an outer layer, wherein
the inner layer comprises yttria-stabilized zirconia and has a thickness from about 200 micrometers to about 300 micrometers; and
the outer layer comprises yttria-stabilized zirconia with an yttria content greater than 38 weight percent and is more resistant to infiltration by nominal CMAS relative to 8 weight percent yttria-stabilized zirconia at a temperature of 1300 degrees Celsius,
wherein a thickness of the outer layer is greater than the thickness of the inner layer.
10. An article, comprising:
a substrate; and
a plurality of coating layers disposed on the substrate, the plurality of coating layers comprising an inner coating layer and an outer coating layer, wherein the inner coating layer comprises a first YSZ material having an yttria content between 6 and 9 weight percent, a thermal resistance in a range from 9 ×10 −5 to 23 ×10 −5 degree Kelvin per watt, and a thickness of from 200 to 300 μm, and the outer coating comprises a second YSZ material having an yttria content greater than 38 weight percent and a thickness such that a total thermal resistance of the plurality of coating layers is at least 24 ×10 −5 degree Kelvin per watt and wherein the thickness of the outer coating layer is greater than the thickness of the inner coating layer.
11. The article of claim 10 , wherein the inner layer has a thickness of about 250 μm and the outer layer is 55YSZ having a thickness of about 380 μm.
12. The article of claim 11 , wherein the inner layer and the outer layer are air plasma sprayed dense vertically cracked layers.
13. The article of claim 1 , wherein wherein the inner layer has a thickness of about 250 μm and the outer layer is 55YSZ having a thickness of about 380 μm.
14. The article of claim 9 , wherein wherein the inner layer has a thickness of about 250 μm and the outer layer is 55YSZ having a thickness of about 380 μm.