Static dissipative fuel tank coatings and methods

• US 9,221,547 B2
• Filed: 06/25/2010
• Issued: 12/29/2015
• Est. Priority Date: 06/25/2010
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Chao, Alexander, Steele, Eric Richard, Pate, Kevin Darrell, Hurt, Megan J., Anderson, Michael G., Ward, Theresa Nadine, Clements, Judson Sid
• Primary Examiner(s): Jackson, Stephen W
• Assistant Examiner(s): HOANG, ANN THI
• Application Number:
  US12/824,138
• Publication Number:
  US 20110315818A1
• Time in Patent Office: 2,013 Days
• Field of Search: 361/218
• US Class Current: 1/1
• CPC Class Codes: B64D 37/32 Safety measures not otherwise provided for, e.g. preventing explosive conditions extinguishing or preventing fires in aircraft A62C
• CPC Class Codes: B64D 45/02 Lightning protectors; Static dischargers in general H01T
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

There is provided a method for mitigating static discharge in a fuel container. The method provides a static dissipative coating having a volume resistivity of 1.0×10⁹ Ω-m (ohm-meter) or less when measured at 40 V (volts) or less, having a surface resistivity of 1.0×10¹¹ Ω/sq (ohm per square) or less when measured at 100 V (volts) or less, having a breakdown voltage of 4000 V (volts) or less, and having a charge decay of 60 seconds or less. The method further provides applying the static dissipative coating to a surface of the fuel container to form a coated surface.

Claims

1. A method for mitigating static discharge in a fuel container, the method comprising:

applying a non-chromated static dissipative coating directly to a surface of the fuel container, the fuel container comprising one or more composite components and one or more metal components, wherein the coating is only applied over the one or more composite components as a topmost layer on the one or more composite components, the static dissipative coating having a volume resistivity of 1.0×

10⁹ Ω

-m (ohm-meter) or less when measured at 40 V (volts) or less, having a surface resistivity of 1.0×

10¹¹ Ω

/sq (ohm per square) or less when measured at 100 V (volts) or less, having a breakdown voltage of 4000 V (volts) or less, and having a charge decay of 60 seconds or less.

2. The method of claim 1, further comprising prior to applying the static dissipative coating to the surface, treating the surface of the fuel container in order to clean the surface and increase adhesion of the static dissipative coating to the surface.

3. The method of claim 1, further comprising after applying the static dissipative coating to the surface, curing the coated surface of the fuel container for an effective time period in a range of from about 30 minutes to about 7 days and at an effective temperature in a range of from about 55°

F. (degrees Fahrenheit) to about 210°

F. (degrees Fahrenheit).

4. The method of claim 1, wherein the static dissipative coating has a resistivity of 1.0×

10⁸ Ω

-m (ohm-meter) or less when measured at 40 V (volts) or less.

5. The method of claim 1, wherein the static dissipative coating is grounded to provide a bleed path for a static charge and enables dissipation of a build-up of the static charge during refueling to prevent creation of propagating brush discharge (PBD).

6. The method of claim 1, wherein the static dissipative coating is chemical resistant to water, hydraulic fluid, and jet fuel.

7. The method of claim 1, wherein the static dissipative coating is chemically compatible with one or more sealants, enables adhesion of the one or more sealants to one or more components in the fuel container, and provides a barrier between any ultraviolet radiation and the surface of the fuel container.

8. The method of claim 1, wherein the static dissipative coating does not impact design for lightning direct effects protection.

9. The method of claim 1, wherein the one or more metal components comprises one or more of aluminum components, titanium components, and corrosion-resistant steel (CRES) components.

10. The method of claim 1, wherein the static dissipative coating does not induce galvanic corrosion.

11. A method for mitigating static discharge in an aircraft fuel tank, the method comprising:

applying a non-chromated static dissipative coating directly to a surface of the aircraft fuel tank, the aircraft fuel tank comprising one or more composite components and one or more metal components, wherein the coating is only applied over the one or more composite components as a topmost layer on the one or more composite components, the static dissipative coating having a volume resistivity of 1.0×

10⁹ Ω

-m (ohm-meter) or less when measured at 40 V (volts) or less, having a surface resistivity of 1.0×

10¹¹ Ω

/sq (ohm per square) or less when measured at 100 V (volts) or less, having a breakdown voltage of 4000 V (volts) or less, and having a charge decay of 60 seconds or less, wherein the static dissipative coating does not impact design for lightning direct effects protection; and

,

curing the coating.

12. The method of claim 11, further comprising prior to applying the static dissipative coating directly to the surface of the aircraft fuel tank, treating the surface of the aircraft fuel tank in order to clean the surface and increase adhesion of the static dissipative coating to the surface.

13. A static dissipative non-chromated coating for mitigating static discharge in a fuel container, the fuel container comprising one or more composite components and one or more metal components, the coating applied directly over only the one or more composite components as a topmost layer, the coating having a volume resistivity of 1.0×

10⁹ Ω

-m (ohm-meter) or less when measured at 40 V (volts) or less, having a surface resistivity of 1.0×

10¹¹ Ω

/sq (ohm per square) or less when measured at 100 V (volts) or less, having a breakdown voltage of 4000 V (volts) or less, and having a charge decay of 60 seconds or less.

14. The coating of claim 13, wherein the coating has a resistivity of 1.0×

10⁸ Ω

-m (ohm-meter) or less when measured at 40 V (volts) or less.

15. The coating of claim 13, wherein the coating is grounded to provide a bleed path for a static charge and enables dissipation of a build-up of the static charge during refueling to prevent creation of a propagating brush discharge (PBD).

16. The coating of claim 13, wherein the one or more metal components comprises one or more of aluminum components, titanium components, and corrosion-resistant steel (CRES) components.

17. The method of claim 13, wherein the coating does not induce galvanic corrosion.

18. The coating of claim 13, wherein the fuel container comprises an aircraft fuel tank.

19. The coating of claim 13, wherein the coating does not impact design for lightning direct effects protection.

20. An aircraft comprising:

a fuselage;

a wing operatively coupled to the fuselage;

a fuel tank disposed inside at least one of the fuselage and the wing, the fuel tank comprising one or more composite components comprising one of a carbon-fiber reinforced plastic (CFRP), a glass-fiber reinforced plastic (GFRP), a fiber-reinforced polyamide, an aramid-reinforced material, fiberglass, a polyester resin, a vinylester resin, and an epoxy resin, and the fuel tank further comprising one or more metal components comprising one or more of aluminum components, titanium components, and corrosion-resistant steel (CRES) components; and

,

a non-chromated static dissipative coating applied directly over a surface of only the one or more composite components of the fuel tank as a topmost layer, wherein the static dissipative coating has a volume resistivity of 1.0×

10⁹ Ω

-m (ohm-meter) or less when measured at 40 V (volts) or less, has a surface resistivity of 1.0×

10¹¹ Ω

/sq (ohm per square) or less when measured at 100 V (volts) or less, has a breakdown voltage of 4000 V (volts) or less, and has a charge decay of 60 seconds or less, and further wherein the static dissipative coating does not impact design for lightning direct effects protection.