Abradable material
A blade outer airseal comprising a body having: an inner diameter (ID) surface; an outer diameter (OD) surface; a leading end; a trailing end; a metallic substrate; and a coating system atop the substrate along at least a portion of the inner diameter surface. At least over a first area of the inner diameter surface, the coating system comprises an abradable layer comprising a metallic matrix and a filler. The filler forms at least 20% by volume of the abradable layer with agglomerates or aggregates of oxide particles, the oxide particles having a D50 size ≤200 nm.
1. A blade outer airseal comprising:
a body comprising:
an inner diameter (ID) surface;
an outer diameter (OD) surface;
a leading end;
a trailing end;
a metallic substrate; and
a coating system atop the substrate along at least a portion of the inner diameter surface,
wherein:
at least over a first area of the inner diameter surface, the coating system comprises an abradable layer comprising a metallic matrix and a filler;
the filler comprises aggregates of oxide particles, the oxide particles having a D50 size ≤200 nm;
the aggregates comprise alumina and magnesia aggregates that occupy at least 40% by volume of the abradable layer; and
the magnesia forms 0.1% to 2% weight percent of the total of alumina and magnesia.
2. The blade outer airseal of claim 1 wherein:
the particles having a D50 size ≤200 nm form at least 50 weight percent of the aggregates.
3. The blade outer airseal of claim 1 wherein:
a D50 size of the aggregates is 10 to 150 micrometers.
4. The blade outer airseal of claim 1 wherein:
less than 4 volume percent, if any, of the abradable layer is re-solidified metal oxide of the aggregates; and
a D50 size of the aggregates is 22 to 45 micrometers.
5. The blade outer airseal of claim 1 wherein:
a D50 size of the aggregates is 6 to 45 micrometers.
6. The blade outer airseal of claim 1 wherein the metallic matrix comprises:
an MCrAlY.
7. The blade outer airseal of claim 1 wherein:
the matrix forms 20-35 volume % of the abradable layer.
8. The blade outer airseal of claim 1 wherein:
a Vickers hardness of the abradable layer is ≤300 with a 50 g load.
9. The blade outer airseal of claim 1 wherein:
the matrix forms 20-45 volume % of the abradable layer.
10. The blade outer airseal of claim 1 wherein:
the abradable layer has a cohesive bond strength of 500-3000 psi.
11. The blade outer airseal of claim 1 wherein:
the abradable layer has 40-80% said filler by volume.
12. A method for manufacturing the blade outer airseal of claim 1 the method comprising:
thermal spray of the abradable layer.
13. The method of claim 12 wherein:
the thermal spray uses a source material for the filler having the aggregates.
14. The method of claim 13 wherein:
the source material comprises said aggregates having particle D50 size of 10 nm to 50 nm; and
the aggregates in the source material have a compressive strength of 50 to 100 psi as determined by bulk powder compressibility.
15. The method of claim 13 wherein:
the source material comprises said aggregates having particle D50 size of 10 nm to 50 nm; and
said aggregates in said source material have 70-90% porosity.
16. The method of claim 13 wherein:
the particles having a D50 size ≤200 nm form at least 50 weight percent of the aggregates.
17. The method of claim 13 wherein:
a D50 size of the aggregates is 10 to 150 micrometers.
18. The method of claim 13 wherein:
less than 4 volume percent, if any, of the abradable layer is re-solidified metal oxide of the aggregates; and
a D50 size of the aggregates is 22 to 45 micrometers.
19. The method of claim 13 wherein:
a D50 size of the aggregates is 6 to 45 micrometers.
20. The method of claim 13 wherein the metallic matrix comprises:
an MCrAlY.
21. The method of claim 13 wherein:
the matrix forms 20-35 volume % of the abradable layer.