Coated articles and method for making

Abstract

An article includes a substrate comprising a precipitate-strengthened alloy and a coating disposed over the substrate. The alloy comprises a) a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers; or b) a population of gamma-double-prime precipitates having a median size less than about 300 nanometers. The coating comprises at least two elements, and further comprises a plurality of prior particles. At least a portion of the coating is substantially free of rapid solidification artifacts. Methods for fabricating the article and for processing powder useful for fabricating the article are also provided.

1 - 18 . (canceled) 
     
     
         19 . A method comprising:
 heat-treating a quantity of metallic powder, the powder having particulates comprising at least two elements and a plurality of rapid solidification artifacts present within the particulates, wherein the heat-treating is performed at a combination of time and temperature effective to remove substantially all of the rapid solidification artifacts from the powder, thereby forming a processed powder having a desired particle size distribution.   
     
     
         20 . The method of  claim 19 , wherein heat-treating further includes agitating the powder during heat-treatment. 
     
     
         21 . The method of  claim 19 , further comprising mechanically processing sintered material formed during the heat-treating. 
     
     
         22 . The method of  claim 21 , wherein mechanically processing comprises milling the sintered material. 
     
     
         23 . The method of  claim 19 , further comprising disposing a coating material on a substrate, wherein the processed powder is used as a feedstock for the coating material. 
     
     
         24 . The method of  claim 23 , wherein the disposing step comprises spraying the feedstock using a technique that does not melt a substantial portion of the particulates in the feedstock. 
     
     
         25 . The method of  claim 24 , wherein the technique includes cold-spraying, flame spraying, liquid injection flame spraying, air plasma spraying, liquid injection air plasma spraying, high-velocity oxyfuel spraying, liquid injection high velocity oxyfuel spraying, high-velocity air-fuel spraying, or liquid injection high-velocity air-fuel spraying. 
     
     
         26 . The method of  claim 24 , wherein the technique includes liquid injection high velocity air-fuel spraying. 
     
     
         27 . The method of  claim 23 , wherein the substrate comprises a nickel-based superalloy, a nickel-iron-based superalloy, or a cobalt-based superalloy. 
     
     
         28 . The method of claim  9 , wherein the particulates comprise a NiCrAlY composition. 
     
     
         29 . The method of  claim 28 , wherein the composition comprises cobalt; from about 28 percent to about 35 percent nickel; from about 17 percent to about 25 percent chromium; from about 5 percent to about 15 percent aluminum; and from about 0.01 to about 1 percent yttrium. 
     
     
         30 . The method of  claim 28 , wherein the coating comprises beta phase, at least about 25 percent gamma phase by volume, and less than about 1 percent sigma phase by volume. 
     
     
         31 . A method comprising:
 heat-treating a quantity of powder having particulates comprising a MCrAlX composition at a temperature in a range from about 925 degrees Celsius to about 1200 degrees Celsius for at least about 5 minutes to form a processed powder; and   disposing a coating material on a substrate using cold-spraying, flame spraying, air plasma spraying, high-velocity oxyfuel spraying, or high-velocity air-fuel spraying, wherein the processed powder is used as a feedstock for the coating material, and wherein the substrate comprises a nickel-based superalloy;   wherein the disposing step comprises spraying the feedstock using a technique that does not melt a substantial portion of the particulates in the feedstock.   
     
     
         32 . A method comprising:
 disposing a coating onto a substrate by spraying a feedstock, the feedstock comprising a plurality of particulates comprising at least two elements and having at least a portion of the plurality of particulates substantially free of rapid solidification artifacts;   wherein spraying the feedstock comprises using a deposition technique that does not melt a substantial portion of the particulates in the feedstock;   wherein the substrate comprises a precipitate-strengthened alloy, the alloy comprising   a) a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers; or b) a population of gamma-double-prime precipitates having a median size less than about 300 nanometers.   
     
     
         33 . The method of  claim 32 , wherein the substrate comprises a nickel-based superalloy, a nickel-iron-based superalloy, or a cobalt-based superalloy. 
     
     
         34 . The method of  claim 32 , wherein the feedstock comprises a MCrAlY composition. 
     
     
         35 . The method of claim of  claim 34 , wherein the feedstock comprises cobalt; from about 28 percent to about 35 percent nickel; from about 17 percent to about 25 percent chromium; from about 5 percent to about 15 percent aluminum; and from about 0.01 to about 1 percent yttrium. 
     
     
         36 . The method of  claim 34 , wherein the feedstock comprises a gamma phase and a beta phase. 
     
     
         37 . The method of  claim 36 , wherein the feedstock includes less than about 1 percent sigma phase by volume. 
     
     
         38 . The method of  claim 36 , wherein the coating is disposed in direct contact with the substrate at an interface, and wherein an interdiffusion zone extending from the interface into the substrate has a thickness of less than about 5 micrometers. 
     
     
         39 . A method comprising:
 disposing a coating onto a substrate by spraying a feedstock, the feedstock comprising a plurality of particulates comprising a MCrAlX composition and having at least a portion of the plurality of particulates substantially free of rapid solidification artifacts;   wherein spraying the feedstock comprises using a deposition technique that does not melt a substantial portion of the particulates in the feedstock;   wherein the substrate comprises a nickel-based superalloy comprising a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers.