Abradable Material

Abstract

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 .- 17 . (canceled) 
     
     
         18 . A method for manufacturing a blade outer airseal, the method comprising thermal spray of:
 a metallic matrix; and   a filler,   
       wherein:
 the filler comprises oxide particles; and 
 the filler is sprayed from a source having agglomerates or aggregates of said oxide particles, said particles having a D50 size of ≤200 nm. 
 
     
     
         19 . The method of  claim 18  wherein the D50 size is:
 10 nm to 50 nm. 
 
     
     
         20 . The method of  claim 19  wherein:
 the metallic matrix is sprayed from a source having particles of the matrix with a D50 size of 22-90 micrometers. 
 
     
     
         21 . The method of  claim 20  wherein:
 the filler is sprayed from the source having the aggregates. 
 
     
     
         22 . The method of  claim 21  wherein:
 the particles have a D50 size ≤200 nm form at least 50 weight percent of the aggregates. 
 
     
     
         23 . The method of  claim 21  further comprising forming the aggregates by calcining and sintering agglomerates. 
     
     
         24 . The method of  claim 23  further comprising forming the agglomerates by drying a slurry. 
     
     
         25 . The method of  claim 24  wherein the filler comprises:
 alumina, silica, titania, zirconia, hafnia, dysprosia, gadolinia, yttria, magnesia, nickel oxide, and/or chromia forming at least 40% by volume of the abradable layer. 
 
     
     
         26 . The method of  claim 24  wherein the filler comprises:
 alumina and magnesia forming aggregates that occupy at least 40% by volume of the abradable layer. 
 
     
     
         27 . The method of  claim 26  wherein:
 the magnesia forms 0.1% to 2% weight percent of the total of alumina and magnesia. 
 
     
     
         28 . The method of  claim 24  wherein the metallic matrix comprises an MCrAlY. 
     
     
         29 . The method of  claim 18  wherein the metallic matrix comprises an MCrAlY. 
     
     
         30 . The method of  claim 18  wherein the filler comprises:
 alumina, silica, titania, zirconia, hafnia, dysprosia, gadolinia, yttria, magnesia, nickel oxide, and/or chromia forming at least 40% by volume of the abradable layer. 
 
     
     
         31 . The method of  claim 30  wherein the filler comprises:
 alumina and magnesia forming aggregates that occupy at least 40% by volume of the abradable layer. 
 
     
     
         32 . The method of  claim 31  wherein:
 the magnesia forms 0.1% to 2% weight percent of the total of alumina and magnesia. 
 
     
     
         33 . The method of  claim 18  wherein:
 the metallic matrix is sprayed from a source having particles of the matrix with a D50 size of 22-90 micrometers. 
 
     
     
         34 . The method of  claim 18  wherein:
 the matrix forms 20-35 volume % of the abradable layer. 
 
     
     
         35 . The method of  claim 18  wherein:
 the abradable layer has 30-80% said filler by volume.