WO 2015/034768

PCT7US2014/053373

WHAT IS CLAIMED IS:
1. A method of manufacturing a fuel contacting component that facilitates reducing
coke formation on at least one surface of the fuel contacting component exposed to a liquid
fuel, said method comprising:
applying a slurry composition that includes a powder including aluminum to the at least one surface, wherein the fuel contacting component is formed by an additive manufacturing process;
heat treating the slurry composition to diffuse the aluminum into the at least one surface, wherein heat treating comprises forming a diffusion aluminide coating including a diffusion sublayer on the at least one surface and an additive sublayer on the diffusion sublayer; and
removing the additive sublayer of the diffusion aluminide coating with at least one aqueous solution such that the diffusion sublayer and the at least one surface are substantially unaffected, wherein the diffusion layer facilitates preventing coke formation on the at least one surface.
2. The method of Claim 1 further comprising repeating at least one of the applying, diffusion heat treating, and removing steps at least once.
3. The method of Claim 1 further comprising:
forming a coating residue on the at least one surface after treatment in the aqueous solution; and
removing the coating residue using a technique including at least one of abrasion, tumbling, laser ablation, and ultrasonic agitation.
4. The method of Claim 1 further comprising removing a worn or damaged diffusion aluminide coating prior to applying the slurry composition.
5. The method of Claim 1, wherein applying the slurry composition to the at least one surface further comprises applying the slurry composition to a surface of a fuel nozzle for use in a gas turbine engine.
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WO 2015/034768

PCT7US2014/053373

6. The method of Claim 1, wherein applying the slurry composition to the at least one
surface further comprises applying the slurry composition to at least one surface formed from
one of a nickel-based or cobalt-based superalloy.
7. The method of Claim 1, wherein removing the additive sublayer such that the
diffusion sublayer and the at least one surface are unaffected facilitates reducing surface
roughness of the at least one surface.
8. The method of Claim 1, wherein forming a diffusion aluminide coating comprises forming the diffusion aluminide coating having a thickness within a range between approximately 10 micrometers and approximately 125 micrometers.
9. The method of Claim 1, wherein removing the additive sublayer comprises using an aqueous solution selected from the group including at least one of hydroflourozirconic acid, hydrofluorosilicic acid, hydrochloric acid, or a combination thereof.
10. The method of Claim 1 further comprising immersing the fuel contacting
component having the diffusion aluminide coating in a bath of the aqueous solution for a time
period in a range between approximately 10 minutes and approximately 4 hours.
11. The method of Claim 10 further comprising maintaining the aqueous solution at a temperature in a range between approximately 30°C and approximately 85°C.
12. The method of Claim 1 further comprising applying the heat treatment for a time period in a range between approximately 1 hour and approximately 4 hours.
13. The method of Claim 12 further comprising applying the heat treatment at a
temperature in the range of between approximately 120Q°F and approximately 160Q°F.
14. The method of Claim 1, wherein applying a slurry composition further comprises at least one of spraying the slurry composition onto the at least one surface, immersing the fuel contacting component in a bath of the slurry composition, and vapor phase aluminizing.
15. The method of Claim 1, wherein applying a slurry composition that includes a powder including aluminum further comprises applying a slurry composition that includes a powder that is in a range between about 40 weight percent and about 70 weight percent aluminum.
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WO 2015/034768

PCT7US2014/053373

16. The method of Claim 1, wherein applying a slurry composition that includes a powder further comprises applying a slurry composition that includes a powder including at least one binder selected from the group includmg at least one of colloidal silica, an organic resin, and a combination thereof,
17. The method of Claim 16, wherein applying a slurry composition that includes a powder further comprises applying a slurry composition that includes a powder including an organic stabilizer selected from the group including an alkane diol, glycerol, pentaerythritol, a fat, a carbohydrate, and a combination including at least one of the foregoing organic compounds.
18. The method of Claim 17, wherein applying a slurry composition that includes a powder including aluminum further comprises applying a slurry composition that includes a powder that is in a range between about 20 weight percent and about 40 weight percent colloidal silica and in the range of about 5 weight percent to about 15 weight percent organic stabilizer.
19. The method of Claim 1, wherein applying a slurry composition that includes a powder including aluminum further comprises applying a slurry composition that includes a powder including aluminum that has an average particle size in a range between about 0.5 micrometers and about 100 micrometers.
20. A method of manufacturing a component, said method comprising:
forming a diffusion aluminide coating on a surface of a fuel contacting component formed by additive manufacturing; and
partially removing the diffusion aluminide coating from the surface such that a remaining portion of the diffusion aluminide coating facilitates preventing coke formation on the fuel contacting component surface.
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