Closed pore ceramic composite article
A composite article includes a substrate and a thermal barrier secured to the substrate. The thermal barrier includes a plurality of closed pores within a ceramic matrix. For example, the closed pores comprise 20 vol % to 80 vol % of the thermal barrier.
1. A composite article comprising:
a substrate; and
a thermal barrier secured to the substrate, the thermal barrier comprising a plurality of closed pores within a ceramic matrix, wherein the ceramic matrix comprises at least one of yttria stabilized zirconia and molybdenum disilicide.
2. The composite article as recited in claim 1 , wherein the plurality of closed pores are each entirely surrounded by the ceramic matrix.
3. The composite article as recited in claim 1 , wherein the plurality of closed pores comprise about 20 vol % to 80 vol % of the thermal barrier.
4. The composite article as recited in claim 3 , wherein the plurality of closed pores comprise about 33 vol % to 66 vol % of the thermal barrier.
5. The composite article as recited in claim 3 , wherein the plurality of closed pores comprise about 66 vol % of the thermal barrier.
6. The composite article as recited in claim 1 , further comprising a bond coat between the substrate and the thermal barrier.
7. The composite article as recited in claim 1 , wherein the thermal barrier comprises a thickness of about 20 mils to 150 mils.
8. The composite article as recited in claim 7 , wherein the thickness is about 20 mils to 50 mils.
9. The composite article as recited in claim 1 , wherein the plurality of closed pores is an inherent porosity in the ceramic matrix material.
10. The composite article as recited in claim 1 , wherein each of the plurality of closed pores is bounded by a side wall, and the ceramic matrix material is the side wall.
11. The composite article as recited in claim 1 , wherein the ceramic matrix comprises the yttria stabilized zirconia.
12. The composite article as recited in claim 1 , wherein the ceramic matrix comprises the molybdenum disilicide.
13. A method of manufacturing a thermal barrier, comprising:
forming the thermal barrier with a plurality of closed pores within a ceramic matrix, including forming the thermal barrier from a ceramic material having a pore-forming agent including nano-sized ceramic particles and sintering the pore-forming agent to reduce the size of the pore-forming agent and thereby form the closed pores.
14. The method as recited in claim 13 , wherein the ceramic matrix comprises at least one of yttria stabilized zirconia and molybdenum disilicide.
15. The method as recited in claim 14 , wherein the ceramic matrix comprises the molybdenum disilicide.
16. A turbine blade outer air seal comprising:
a body extending between two circumferential sides, a leading edge and a trailing edge, and a radially inner side and a radially outer side; and
a thermal barrier secured to the body, the thermal barrier comprising a plurality of closed pores within a ceramic matrix, wherein the ceramic matrix comprises at least one of yttria stabilized zirconia and molybdenum disilicide.
17. The turbine blade outer air seal as recited in claim 16 , wherein the plurality of closed pores comprise about 33 vol % to 66 vol % of the thermal barrier, and wherein the thermal barrier comprises a thickness between about 20 mils and 50 mils.