Multilayer abradable coatings for high-performance systems

1. A high-performance component comprising:

a substrate; and

a multilayer abradable track adjacent to the substrate, wherein the multilayer abradable track comprises a plurality of alternating layers along a thickness of the multilayer abradable track, wherein the plurality of alternating layers comprises at least two porous abradable layers and at least two dense layers, the plurality of alternating layers alternating between a first porous layer of the at least two porous layers, a first dense layer of the at least two dense layers, a second porous layer of the at least two porous layers, and a second dense layer of the at least two dense layers, wherein a porosity of the at least two dense layers are lower than a porosity of the at least two porous abradable layers, and wherein the first porous layer is furthest from the substrate of the plurality of alternating layers.

2. The high-performance component of claim 1 , wherein the at least two porous abradable layers exhibit a porosity between 10 vol. % and 40 vol. %.

3. The high-performance component of claim 1 , wherein the at least two dense layers exhibit a porosity less than or equal to 15 vol. %.

4. The high-performance component of claim 1 , wherein the substrate defines a substrate channel comprising the multilayer abradable track.

5. The high-performance component of claim 1 , wherein the substrate defines a major surface, and wherein the multilayer abradable track is disposed on the major surface.

6. The high-performance component of claim 1 , wherein the substrate comprises a ceramic matrix composite.

7. The high-performance component of claim 1 , wherein at least one of the at least two porous abradable layers or the at least two dense layers comprises at least one of aluminum nitride, aluminum diboride, boron carbide, aluminum oxide, mullite, zirconium oxide, carbon, silicon metal, silicon alloy, silicon carbide, silicon nitride, a transition metal nitride, a transition metal boride, a rare earth oxide, a rare earth silicate, a stabilized zirconium oxide, a stabilized hafnium oxide, or barium-strontium-aluminum silicate.

8. The high-performance component of claim 1 , wherein one or both of the at least two porous abradable layers or the at least two dense layers comprise a thermal sprayed composition.

9. The high-performance component of claim 1 , wherein the multilayer abradable track further defines an abradable channel comprising a porous abradable composition.

10. The high-performance component of claim 1 , wherein the high-performance component comprises a substantially cylindrical shroud, and wherein the multilayer abradable track runs along a cylindrical surface defined by the substantially cylindrical shroud.

11. The high-performance component of claim 10 , wherein the multilayer abradable track defines a substantially cylindrical abrasion surface.

12. A high-performance system comprising:

the high-performance component of claim 1 ; and

a rotating component configured to contact an abradable surface defined by the multilayer abradable track with a portion of the rotating component.

13. A method comprising:

forming a multilayer abradable track on a substrate, wherein the multilayer abradable track comprises a plurality of alternating layers along a thickness of the multilayer abradable track, wherein the plurality of alternating layers comprises at least two porous abradable layers and at least two dense layers, the plurality of alternating layers alternating between a first porous layer of the at least two porous layers, a first dense layer of the at least two dense layers, a second porous layer of the at least two porous layers, and a second dense layer of the at least two dense layers,

wherein each porous layer of the at least two porous layers is formed by at least thermal spraying a first precursor composition toward the substrate of a high-performance component to form the porous abradable layer,

wherein each dense layer of the at least two dense layers is formed by at least thermal spraying a second precursor composition toward the substrate to form the dense layer,

wherein a porosity of the at least two dense layers is lower than a porosity of the at least two porous abradable layers,

wherein the first and the second precursor composition comprise a respective matrix composition, and wherein the respective matrix composition comprises at least one of aluminum nitride, aluminum diboride, boron carbide, aluminum oxide, mullite, zirconium oxide, carbon, silicon metal, silicon alloy, silicon carbide, silicon nitride, a transition metal nitride, a transition metal boride, a rare earth oxide, a rare earth silicate, a stabilized zirconium oxide, a stabilized hafnium oxide, or barium-strontium-aluminum silicate, and

wherein the respective matrix composition of the first precursor composition is the same as the respective matrix composition of the second precursor composition.

14. The method of claim 13 , wherein the first precursor composition comprises a porosity-creating additive, and wherein the porosity-creating additive comprises one or more of graphite, hexagonal boron nitride, a polymer, a polyester.

15. The method of claim 14 , wherein the concentration of the porosity-creating additive in the first precursor composition is controlled to cause the at least two porous abradable layers to exhibit a porosity between 10 vol. % and 40 vol. %.

16. The method of claim 13 , wherein the second precursor composition comprises the porosity-creating additive, wherein the concentration of the porosity-creating additive in the second precursor composition is controlled to cause the at least two dense layers to exhibit a porosity less than or equal to 15 vol. %.

17. The method of claim 13 , further comprising at least one of fabricating the substrate to define a substrate channel or fabricating the multilayer abradable track to define an abradable channel.