Light-weight, highly-conductive repair material
A light-weight, highly-conductive material useful for repairing a lightning protection system in an aircraft. The material includes a nonwoven carbon fiber veil and a metal coating covering the veil. The veil includes a plurality of carbon fibers looped randomly throughout the veil and a binder material that binds the plurality of fibers together. The metal coating covers a portion of a surface of the plurality of bound fibers of the veil, and preferably the entire surface of both the plurality of bound fibers and the binder material, forming a highly-conductive network that follows the shape of the plurality of fibers in the veil. The areal weight is in a range from at least 5 grams per square meter (gsm), up to 12 gsm, and the sheet resistance is in a range from at least 0.5 ohms per square (Ω/□), up to 2Ω/□.
1. A light-weight, highly-conductive material useful for repairing a lightning protection system in an aircraft, the material comprising:
a nonwoven carbon fiber veil, the veil comprising:
a plurality of carbon fibers looped randomly throughout the veil; and
a binder material that binds the plurality of carbon fibers together forming the veil; and
a metal coating covering the entire surface of both the plurality of bound fibers and the binder material;
wherein the metal coating forms a highly-conductive network that follows the shape of the plurality of fibers in the veil;
wherein the areal weight of the material is in a range from at least 5 grams per square meter (gsm), up to 12 gsm; and
wherein the sheet resistance of the material is in a range from at least 0.5 ohms per square (Ω/□), up to 2Ω/□.
2. The material of claim 1 , the material manufactured as a broad good and supplied as a sheet or a patch.
3. The material of claim 2 , the sheet or the patch having a length and a width, the ratio between the length and width in a range from 0.5:1, up to 2:1.
4. The material of claim 1 , the material manufactured and supplied as a broad good.
5. The material of claim 4 , the broad good having a length and a width, the ratio of the length to the width defining an aspect ratio, the aspect ratio in a range from at least 10:1, up to 10,000:1.
6. The material of claim 4 , the width of the broad good in a range from at least 12 inches (30.48 centimeters), up to 72 inches (182.88 centimeters).
7. The material of claim 1 , wherein the areal weight of the nonwoven carbon fiber veil is approximately 7 gsm.
8. The material of claim 1 , wherein each fiber has a diameter of at least about 1 micron, and up to about 10 microns, wherein each fiber has a length of at least 1 mm, and up to 10 mm, and wherein each fiber has an aspect ratio of about 10,000:1, down to about 1,000:1.
9. The material of claim 1 , wherein the binder material comprises a polymeric binder.
10. The material of claim 1 , wherein the binder material is a polystyrene-acrylic binder.
11. The material of claim 1 , wherein the areal weight of the binder material within the material is at least 0.25 grams per square meter (gsm), up to 1.20 gsm.
12. The material of claim 1 , wherein the metal coating is applied to the entire surface of both the plurality of bound fibers and the binder material through an electroless plating (EL) process.
13. The material of claim 1 , the metal coating comprising nickel.
14. The material of claim 1 , wherein the areal weight of the metal coating is at least 3 grams per square meter (gsm), up to 5 gsm.
15. The material of claim 1 , wherein the metal coating comprises at least 30% by weight up to 42% by weight of the total mass of the material.
16. The material of claim 1 , wherein the highly-conductive network provides a shielding effect of at least about 40 decibels (dB), up to about 80 dB, from 1-8.5 gigahertz (GHz).
17. The material of claim 1 , wherein when applied to a surface of an aircraft and electrically coupled to a lightning-strike protection system located therein, the material provides at least one of:
electrical continuity between a lightning-strike protection layer and a patch made to the lightning-strike protection layer;
protection from a high intensity radiated field (HIRF); and
protection from a lightning-strike to or proximate the aircraft.
18. The material of claim 1 , wherein when applied to a surface of an aircraft, the material provides Zone 1A lightning-strike protection for the aircraft.
19. A method of repairing a lightning protection system in an aircraft that has sustained damage, the system comprising a carbon fiber composite structure including an expanded copper foil (ECF), the method comprising the steps of:
removing at least one of paint, primer, resin and composite surrounding the damage to expose a portion of the ECF;
cutting an ECF patch to fit the damaged area;
inserting the ECF patch into the damaged area;
placing a piece of the light-weight, highly-conductive material of claim 1 over the ECF patch and the exposed portion of the ECF surrounding the damage, the material forming a low impedance electrical connection between the ECF patch and the exposed portion of the ECF; and
repairing any composite that was removed to expose the portion of the ECF.
20. The method of claim 19 , wherein the damage was caused by a lightning strike.