Applying cold spray erosion protection to an airfoil

1. A method for applying an abrasion coating to a fiber-reinforced composite substrate, the method comprising:

applying a bond layer to the fiber-reinforced composite substrate by emitting a first gas stream including a first metal powder at a first speed below supersonic speed; and

applying a cold spray deposit layer to the bond layer by emitting a second gas stream including a second metal powder at a second speed above supersonic speed.

2. The method of claim 1 , further comprising:

applying the bond layer with a supersonic nozzle of a High Pressure Cold Spray (HPCS) system; and

applying the cold spray deposit layer with the supersonic nozzle of the HPCS system.

3. The method of claim 2 , further comprising:

setting a gas pressure of the HPCS system to a first pressure between 100-400 pounds per square inch (psi) for applying the bond layer; and

setting the gas pressure of the HPCS system to a second pressure between 300-1,000 psi for applying the cold spray deposit layer.

4. The method of claim 2 , further comprising:

setting a standoff distance of the supersonic nozzle to approximately 1.5 inches for the bond layer and to approximately 1 inch for the cold spray deposit layer.

5. The method of claim 2 , further comprising:

setting a heater of the HPCS system to a first temperature between 200-300 degrees Celsius for applying the bond layer; and

increasing the heater to a second temperature between 300-1,000 degrees Celsius for applying the cold spray deposit layer.

6. The method of claim 1 , wherein:

the fiber-reinforced composite substrate includes a leading edge of an aircraft airfoil.

7. The method of claim 1 , wherein:

the first metal powder includes a majority of non-spherical particles and a minority of spherical particles; and

the second metal powder includes a majority of spherical particles and a minority of non-spherical particles.

8. The method of claim 1 , wherein:

the first metal powder has a tensile modulus in a range between 5-15 million pounds per square inch (msi); and

the second metal powder has a tensile modulus in a range between 10-60 msi.

9. The method of claim 1 , wherein:

the first metal powder is one or more of aluminum, titanium, niobium, and alloys thereof.

10. The method of claim 1 , wherein:

the second metal powder includes metal particles comprising one or more of tungsten carbide, titanium, cobalt, steel, nickel, aluminum, niobium, and alloys thereof.

11. The method of claim 1 , wherein:

the fiber-reinforced composite substrate includes a thermoplastic resin matrix of Polyetheretherketone (PEEK); and

the fiber-reinforced composite substrate includes a resin portion on top of the PEEK, the resin portion having a layer thickness between 0.001 to 0.10 inches.

12. The method of claim 1 , wherein:

the bond layer has a layer thickness between 0.001 to 0.05 inches.

13. The method of claim 1 , wherein:

the cold spray deposit layer has a layer thickness between 0.005 to 0.200 inches.

14. The method of claim 1 , further comprising:

setting the second speed of the second gas stream based on one or more properties of the fiber-reinforced composite substrate.

15. The method of claim 14 , wherein:

the one or more properties of the fiber-reinforced composite substrate include at least one of a tensile strength, a hardness, and a thickness of a resin portion.

16. The method of claim 1 , further comprising:

restoring a protective coating of an airfoil by applying the bond layer and the cold spray deposit layer.

17. The method of claim 1 , further comprising:

controlling particle concentration in the first gas stream and the second gas stream so that the bond layer has a larger particle size distribution than the cold spray deposit layer.

18. The method of claim 1 , further comprising:

applying the bond layer with a nozzle of a Low Pressure Cold Spray (LPCS) system; and

applying the cold spray deposit layer with a supersonic nozzle of a High Pressure Cold Spray (HPCS) system.

19. The method of claim 18 , further comprising:

setting a gas pressure of the LPCS system to a first pressure between 100-400 pounds per square inch (psi) for applying the bond layer; and

setting a gas pressure of the HPCS system to a second pressure between 300-1,000 psi for applying the cold spray deposit layer.

20. The method of claim 18 , further comprising:

setting a heater of the LPCS system to a first temperature between 200-300 degrees Celsius for applying the bond layer; and

setting a heater of the HPCS system to a second temperature between 300-1,000 degrees Celsius for applying the cold spray deposit layer.