COATING MATERIAL FOR A SURFACE OF AN AIRCRAFT WITH LIGHTNING PROTECTION

Abstract

A coating material for a surface of an aircraft includes a polymer-based or rubber-based dielectric matrix material, and first flakes of a metallic and/or soft-magnetic, electrically conductive material that are embedded into the matrix material, wherein the first flakes are geometrically two-dimensional and have a ratio of thickness to average diameter of 1:3 or less, and wherein the first flakes are separated from one another in the matrix material and/or have an electrically non-conductive coating.

Claims

1. A coating material for a surface of an aircraft, comprising: a polymer-based or rubber-based dielectric matrix material; and first flakes of a metallic and/or soft-magnetic, electrically conductive material that are embedded into the matrix material, wherein the flakes in the coating material are geometrically two-dimensional and have a ratio of thickness to average diameter of 1:3 or less, and wherein the flakes in the coating material are separated from one another in the matrix material and/or have a non-conductive coating.

2. The coating material of claim 1, wherein thickness of the flakes in the coating material is within a range from 0.1 m to 5 m.

3. The coating material of claim 1, wherein an average diameter of the flakes in the coating material is within a range from 1 m to 25 m.

4. The coating material of claim 1, wherein the flakes in the coating material are aligned essentially parallel to the surface of the aircraft.

5. The coating material of claim 1, wherein a content by volume of the flakes in the coating material is within a range from 5% to 40%, or from 20% to 35%.

6. The coating material of claim 1, wherein the first flakes have an electrically insulating coating comprising silicon dioxide and/or aluminum oxide.

7. The coating material of claim 1, wherein a material of the first flakes includes elements of iron, nickel, zinc, cobalt, copper, magnesium, cadmium, barium, strontium, silicon, germanium, oxygen, and/or an alloy or an intermetallic compound of the elements.

8. The coating material of claim 1, comprising second flakes of a metallic material that differ from a material of the first flakes and has an infrared emission level of not more than 0.2, and wherein the second flakes are embedded into the matrix material together with the first flakes.

9. An aircraft having at least one component having a surface, wherein the surface of the at least one component includes the coating material of claim 1.

10. The aircraft of claim 9, wherein the surface has two or more sections, and wherein the coating material in at least one of the sections has a different pattern and/or a different proportion by volume than in another section.

11. The aircraft of claim 9, wherein some of the first flakes are connected to ground by at least one electrical terminal point.

12. The aircraft of claim 9, wherein the at least one component is a low-observable component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Working examples are discussed in detail hereinafter with reference to the appended drawings. The diagrams are schematic and not true to scale. Identical reference numerals relate to identical or similar elements. The figures show:

[0028] FIG. 1 a schematic diagram of a cross section of a component having a surface and a coating material present at the surface in one working example.

[0029] FIG. 2 a schematic diagram of the cross section from FIG. 1 with a lightning strike hitting the coating material.

[0030] FIG. 3 a detail diagram of the coating material.

[0031] FIG. 4 an aircraft having a coating material on at least one component.

DETAILED DESCRIPTION

[0032] FIG. 1 shows a component 2 of an aircraft in a schematic part-section diagram. The component 2 could be formed from a fiber composite material, for example a carbon fiber-reinforced plastic. A surface 4 has a coating material 6 that comprises a polymer- or rubber-based dielectric matrix material 8, into which are embedded first flakes 10 of a metallic and/or soft-magnetic, electrically conductive material. The first flakes 10 are flat and have a ratio of thickness to average diameter of 1:3 or less. It would optionally also be possible to additionally incorporate second flakes 11 that are shown here by dotted lines. These could consist of a metallic material or an alloy other than the material of the first flakes 10.

[0033] The flakes 10 and optionally 11 are distributed randomly in the matrix material 8 and could form a content by volume in the coating material 6 within a range from 5% to 40% and preferably from 20% to 35%. This means that the flakes 10 and optionally 11 in the total volume of the coating material 6 have a proportion of preferably 25% to 35%.

[0034] The average diameter of the flakes 10 and optionally 11 is within a range from 1 m to 25 m. The thickness thereof starts by way of example at 0.1 m. The flakes 10 and optionally 11 are preferably aligned parallel to the surface 4. Thermal radiation which is emitted outward from the interior of the aircraft 2 is reflected inward by the first flakes 10 and/or the second flakes 11, if provided. The infrared emission of the aircraft 2 is significantly reduced as a result.

[0035] The metallic or soft-magnetic material can additionally achieve improved radar absorption compared to the use of metallic pellets since the surface area of the individual first flakes 10 is much greater than the surface area of customarily used metal pellets that could have a diameter over and above 1 m. The material of the first flakes 10 is preferably selected such that maximum magnetic losses are provided, especially for surface waves, and a high reflection capacity for infrared waves is simultaneously achieved.

[0036] The flakes 10 and optionally 11 have irregularly shaped edges 12 and are spaced apart from one another in the matrix material 8. They consequently do not form a coherent electrically conductive ply or layer, but are insulated from one another in an electrically neutral state. For this purpose, in particular, the first flakes 10 may also have a coating 14. In the case of iron-based first flakes 10, it would thus also be possible to achieve corrosion protection.

[0037] As indicated in FIG. 2, the first flakes 10 extend to one or more terminal points 16 that are electrically connected to a structure 18 in the aircraft. If a lightning strike 20 hits the surface 4, the locally high electrical field strength causes a flashover 22 between adjacent first flakes 10, giving rise to a conductive pathway via which the lightning current can be transported to the next terminal point 16 onto the structure 18.

[0038] FIG. 3 shows the surface 4, which is divided into multiple sections 24 and 26. In order to further improve flashover between the first flakes 10 at low field strength, it is possible to set up a pattern of sections 24 enriched with first flakes 10 and sections 26 without first flakes 10 on the surface 4. These patterns are preferably in accordance with the demands on camouflaging of the aircraft. The pattern may be formed either by applying the coating material comprising first flakes 10 or by applying first flakes solely to the sections 24. The patterns may be linear or curved, regular or irregular, or, if required, may be connected to form a network.

[0039] FIG. 4, finally, shows an example of an aircraft 28 comprising multiple components 30 that can be provided with a coating material 6 of the disclosure herein.

[0040] It should additionally be pointed out that comprising or having do not rule out other elements or steps, and a does not rule out a multitude. Furthermore, it should be pointed out that features or steps that have been described with reference to one of the above working examples can also be used in combination with other features or steps of other above-described working examples. Reference numerals in the claims should not be regarded as a restriction.

[0041] While at least one example embodiment of the invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a, an or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCES

[0042] 2 component [0043] 4 surface [0044] 6 coating material [0045] 8 matrix material [0046] 10 first flakes [0047] 11 second flakes [0048] 12 edge [0049] 14 coating [0050] 16 terminal point [0051] 18 structure [0052] 20 lightning strike [0053] 22 flashover [0054] 24 section (with first flakes) [0055] 26 section (without first flakes)