A coating having multispectral camouflage characteristics

Abstract

The invention relates to a four-layer metal oxide / metal / metal / metal oxide coating that provides multispectral camouflage. Said coating having camouflage characteristics provides thermal, multispectral and electromagnetic protection by offering reflection, absorption and transmission properties against infrared (IR), ultraviolet (UV) and electromagnetic waves. As the ceramic layer, it comprises titanium dioxide (TiO₂), titanium nitride (TiN), zinc oxide (ZnO), zinc nitride (Zn₃N₂), iron (III) oxide (Fe₂O₃), iron (II) oxide (FeO), iron nitride (Fe₂N), aluminium oxide (Al₂O₃), aluminium nitride (AlN), tin oxide (SnO₂), magnesium oxide (MgO), magnesium nitride (Mg₃N₂), calcium oxide (CaO), calcium nitride (Ca₃N₂), cobalt oxide (CoO), tungsten oxide (WO₃), vanadium oxide (V₂O₅), vanadium nitride (VN), manganese oxide (MnO₃), chromium oxide (Cr₂O₃), chromium nitride (CrN), nickel oxide (NiO), boron oxide (B₂O₃), boron nitride (BN) or barium oxide (BaO). As the metal layer, copper (Cu), aluminium (Al), nickel (Ni), cobalt (Co), silver (Ag), gold (Au), iron (Fe), tungsten (W), tin (Sn), zinc (Zn), magnesium (Mg), vanadium (V), chromium (Cr), lead (Pb) or platinum (Pt) is used to provide protection against thermal cameras and UV rays, while electromagnetic waves are blocked. The adhesive-free layered structure is resistant to wear and provides versatile protection for military clothing and mobile platforms by optimising reflection and transmission.

Description

[0001] A COATING HAVING MULTISPECTRAL CAMOUFLAGE CHARACTERISTICS

[0002] Technical Field of the Invention

[0003] The invention relates to a four-layer ceram ic-metal-metal-ceramic coating having multispectral camouflage characteristics. By means of the coating’s layered structure, it possesses the full set of reflectivity (reflection), absorptivity (absorption) and transmissivity properties against radiation of electromagnetic waves across a wide spectrum such as infrared (IR) and ultraviolet (UV). Thus, it provides multispectral protection against electromagnetic waves.

[0004] State of the Art

[0005] Due to the vision systems developed in modem camouflage systems, military personnel, vehicles and equipment are exposed because current camouflage technologies are inadequate, thereby preventing the successful completion of their intended mission. Today, camouflage is not limited to visual concealment; instead, it also attempts to prevent detection in thermal, radar and spectral bands. An example of this is thermal camouflage; these systems regulate surface temperature to hide from the others’ infrared detection devices. Also, currently used camouflage materials are short-lived because they contain paints, prints and similar chemicals that wear quickly in harsh conditions in order to provide visible camouflage.

[0006] Spectral camouflage, another example of modem camouflage systems, is a concealment technology developed to make detection of an object in different spectral bands (for example; visible light, infrared, ultraviolet) more difficult. This technology enables an object to be hidden from different detection systems by manipulating the wavelengths of light reflected to the object’s surroundings. Because modem sensors operate not only with visible light but also with infrared and ultraviolet light, spectral camouflage provides protection against a much wider set of detection methods. For spectral camouflage to be effective, it must have several fundamental properties. First, spectral and thermal signature management must be provided; that is, the light reflected by an object or organism must be in harmony with its environment. This means achieving compatible reflectivity both in visible light and in other spectral bands. Additionally, temperature differences should be minimised and the thermal signature of the object should be concealed. This type of camouflage must also be lightweight, flexible and resistant to environmental conditions. Thus, it can be used on both fixed and moving / mobile targets.

[0007] Multispectral camouflage is an advanced concealment technology that makes detection of an object or person across many different electromagnetic spectrum bands more difficult. While traditional camouflage typically operates only in the visible light spectrum, because modern detection systems also operate with thermal (infrared), radar and other sensors or detectors, multispectral camouflage enables a target to be concealed across these broad detection domains. Such camouflage architectures assist in hiding from radar signals by enabling the object to blend with its environment and by minimising its detectability in different spectral bands. An important characteristic of multispectral camouflage is that it is effective across multiple spectrum bands. For example, while thermal-signature control is provided to prevent detection by infrared sensors, radar detectability is also minimised by materials that absorb or scatter radar signals. In addition, such camouflages must be flexible, lightweight and resistant to environmental conditions, so that they can be used readily in different environments and on moving targets. As a result, multispectral camouflage occupies an important place in modem warfare technologies and provides a significant advantage in both defensive and offensive operations.

[0008] Patent EP1574809B1, which is found in the prior art, relates to a multispectral camouflage based on a heat exchanger managed by its own temperature. Said camouflage system is a multilayer structure obtained by joining layers made of metal, ceramic and polymeric articles by means of an adhesive. It relates to said camouflage material. However, liquid adhesives such as acrylics melt under harsh conditions and lose their functionality. Furthermore, acrylic-derived adhesive resins cause shine because they can pass through the pores of textile surfaces. Therefore, they can be easily detected by both the naked eye and night-vision binoculars.

[0009] Patent application TR2023008293A2 discloses a multilayer protective structure comprising an aluminium layer and acrylic-derived adhesives between polymer surface layers. In addition to the disadvantages caused by the adhesive content of said camouflage coating, the polymer surface present in the invention shortens the overall service life of the product because of insufficient abrasion resistance that arises during product use and / or maintenance.

[0010] Additionally, patent application W02020076252A2 describes a mobile multispectral camouflage net structure that provides concealment against vehicles’ radar and thermal effects even while they are in motion. However, said camouflage is not a material that can be used by personnel in harsh conditions, since it is a protective structure that is heavy, highly susceptible to tearing and burning, and difficult to mount on the object to be concealed. This significantly narrows the field of application of said material.

[0011] Due to the limitations and inadequacies of the existing technical solutions, the adhesives used being detectable by detectors or easily abrasion under harsh conditions, the polymer membranes wearing when in contact with metal surfaces, being water-absorbent and therefore unsuitable for personnel under harsh conditions, having a narrow field of application such as being suitable only for personnel or only for mobile camouflage, and providing insufficient camouflage because of possessing only reflective characteristics, an improvement in the field of multispectral camouflage coating has been rendered necessary.

[0012] Brief Description and Aims of the Invention

[0013] The invention relates to a four-layer ceram ic-metal-metal-ceramic coating having multispectral camouflage characteristics. This layered structure provides multispectral, thermal and electromagnetic protection by combining reflection, absorption and transmission properties across a wide spectrum such as infrared (IR), ultraviolet (UV) and electromagnetic waves. The inorganic metal oxide layers comprise ceramics such as titanium dioxide (TiO2), zinc oxide (ZnO) and iron (III) oxide (Fe2O3), while the metal layers comprise copper (Cu) and / or aluminium (Al) metals. These metals prevent detection by thermal cameras by providing reflection and absorption of thermal radiation. In addition, these layers attenuate ultraviolet rays coming from the sun, thereby offering UV protection, and block electromagnetic waves, thus providing a high level of shielding.

[0014] An aim of the invention is to provide multispectral camouflage. Since the coating that is the subject of the invention possesses high light transmittance in the visible region, it does not cause any change in the existing appearance. Due to the technical properties possessed by the layers, it has the full set of reflectivity (reflection), absorptivity (absorption) and transmissivity characteristics. As a result, it alone provides sufficient multispectral, thermal and electromagnetic protection.

[0015] Another aim of the invention is to obtain a durable camouflage. For this purpose, the developed layers are bonded to each other by high-energy bonds such as interatomic ionic, covalent and metallic bonds. Therefore, it is resistant to wear caused by adhesives that are prone to melting under harsh conditions. In addition, the invention provides a longer-lasting coating since it does not contain polymer membranes that cause polymer-metal surface wear. Furthermore, by means of having a hydrophobic surface, the invention imparts water-repellent properties to the structure when coated on textile material surfaces containing fibres, without the need for additional toxic finishing chemicals.

[0016] Additionally, the invention aims to ensure applicability on a wide variety of surfaces. The coating having camouflage characteristics that is the subject of the invention can be applied to all surfaces such as polymer, textile, glass, aluminium and metal, thus providing protection for individual, mobile and group use depending on the field of application of the coated surface.

[0017] Description of Drawings

[0018] Figure 1. Layered structure of the coating having multispectral camouflage characteristics (A: Outer surface, B: Inner surface)

[0019] Reference Numbers

[0020] 1. Outer ceram ic layer

[0021] 2. Outer metal layer

[0022] 3. Inner metal layer

[0023] 4. Inner ceramic layer

[0024] Detailed Description of the Invention

[0025] The invention relates to a coating designed to provide multispectral camouflage. Said coating comprises the following layers in order from the outer surface to the inner surface, the inner surface being the one to which the coating is applied:

[0026] • an outer ceramic layer (1),

[0027] • an outer metal layer (2), an inner metal layer (3), and

[0028] an inner ceramic layer (4).

[0029] In the coating having multispectral camouflage characteristics that is the subject of the invention, the inner surface described is the side where the coating contacts the surface of the product to which it is applied. The outer surface, on the other hand, is the surface of the coating that remains distant from the applied product.

[0030] In the coating that is the subject of the invention, the outer ceramic layer (1) and the inner ceramic layer (4) each comprise ceramics selected from titanium dioxide (TiO2), titanium nitride (TiN), zinc oxide (ZnO), zinc nitride (Zn3N2), iron (III) oxide (Fe2O3), iron (II) oxide (FeO), iron nitride (Fe2N), aluminium oxide (AI2O3), aluminium nitride (AIN), tin oxide (SnO2), magnesium oxide (MgO), magnesium nitride (Mg3N2), calcium oxide (CaO), calcium nitride (Ca3N2), cobalt oxide (CoO), tungsten oxide (WO3), vanadium oxide (V2O5), vanadium nitride (VN), manganese oxide (MnO3), chromium oxide (Cr2O3), chromium nitride (CrN), nickel oxide (NiO), boron oxide (B2O3), boron nitride (BN) or barium oxide (BaO).

[0031] The outer metal layer (2) and the inner metal layer (3) in the coating that is the subject of the invention each comprise metals selected from copper (Cu), aluminium (Al), nickel (Ni), cobalt (Co), silver (Ag), gold (Au), iron (Fe), tungsten (W), tin (Sn), zinc (Zn), magnesium (Mg), vanadium (V), chromium (Cr), lead (Pb) and platinum (Pt).

[0032] The thickness of each of the outer ceramic layer (1 ), outer metal layer (2), inner metal layer (3) and inner ceramic layer (4) in the coating that is the subject of the invention is between 5 nanometres and 100 micrometres.

[0033] Owing to the presence of high-energy bonds such as ionic or covalent bonds formed as a result of the overlapping of the metal and ceramic layers, the metal layers that could otherwise corrode easily are insulated from different atmospheres under harsh conditions. The presence of ceramics provides technical properties such as corrosion resistance, wear resistance, hardness and thermal resistance. The metallic bonding resulting from the interaction of free electrons in the metal layer causes a resonance that reduces the intensity of the reflected light. As a result of this condition, a surface plasmon effect occurs together with ultraviolet, visible and infrared electromagnetic waves, thereby providing multispectral protective performance. The metals used in the invention have high conductivity and high electron mobility, and exhibit a surface plasmon effect against the wavelength of incident electromagnetic photons.

[0034] The coating that is the subject of the invention provides protective characteristics against the radiation of infrared (IR) rays emitted from the body. Thus, it prevents heat loss and also prevents this radiation from being imaged on thermal cameras. Moreover, the invention has reflection and attenuation capability against ultraviolet (UV) rays coming from the sun. The multilayer coating structure, which provides protection against a wide spectrum of wavelengths, also exhibits a high level of electromagnetic shielding capability. By means of this, the production of a protective product suitable for use in the military and defence sectors becomes possible. By controlling the coating process of the surface in terms of wettability and air permeability, a structure much more durable and compatible with environmental conditions has been achieved.

[0035] Since the layers mentioned in the invention are in the form of thin films below the micrometre scale, there is no need for a polymer coating layer. The greatest advantage of this is that it provides water repellence, breathability and thermal regulation on the surface of the fabric to which it is applied without clogging the naturally porous structure of textile materials.

[0036] Additionally, since the invention can be applied to all surfaces such as polymer, textile, glass, aluminium and metal, it offers the possibility of protection for both individual and group use depending on the field of application of the coated surface.

[0037] The coating that is the subject of the invention is produced by means of the physical vapour deposition (PVD) method. PVD is a coating method that includes radio frequency (RF) magnetron sputtering, which is a fast vacuum technique. A typical magnetron sputtering system consists of a coating chamber, a substrate holder, a target material, a power supply, a vacuum pump, a working gas and cooling water. Films or coatings of different thicknesses can be formed using the RF magnetron sputtering coating system by means of target materials made of pure metals, alloys and compounds. Within this scope, in the PVD method, the layers in the coating system are successively deposited onto the substrate starting from the innermost layer, which is the inner ceramic layer (4), towards the outermost layer, which is the outer ceramic layer (1). The parameters used during the PVD deposition process are as follows: 30-60 W RF power, vacuum level of 4X10-5-4X10-7Torr, deposition pressure level of 1x10’2-2x1 O’2Torr, gas flow of 20-40 seem, and deposition rate of 0-10 A / s. By means of the RF magnetron sputtering method, the outer ceramic layer (1 ), outer metal layer (2), inner metal layer (3) and inner ceramic layer (4) are sequentially obtained from top to bottom.

Claims

CLAIMS1. A coating designed to provide multispectral camouflage, comprising, in order from the outer surface towards the inner surface, the inner surface being the one to which the coating is applied:a. an outer ceramic layer (1 ),b. an outer metal layer (2),c. an inner metal layer (3), andd. and an inner ceramic layer (4).

2. A coating according to claim 1, wherein the outer ceramic layer (1) and the inner ceramic layer (4) each comprise ceramics selected from titanium dioxide (TiO2), titanium nitride (TiN), zinc oxide (ZnO), zinc nitride (Zn3N2), iron (III) oxide (Fe2O3), iron (II) oxide (FeO), iron nitride (Fe2N), aluminium oxide (AI2O3), aluminium nitride (AIN), tin oxide (SnO2), magnesium oxide (MgO), magnesium nitride (Mg3N2), calcium oxide (CaO), calcium nitride (Ca3N2), cobalt oxide (CoO), tungsten oxide (WO3), vanadium oxide (V2O5), vanadium nitride (VN), manganese oxide (MnO3), chromium oxide (Cr2O3), chromium nitride (CrN), nickel oxide (NiO), boron oxide (B2O3), boron nitride (BN) or barium oxide (BaO).

3. A coating according to claim 1 , wherein the outer metal layer (2) and the inner metal layer (3) each comprise metals selected from copper (Cu), aluminium (Al), nickel (Ni), cobalt (Co), silver (Ag), gold (Au), iron (Fe), tungsten (W), tin (Sn), zinc (Zn), magnesium (Mg), vanadium (V), chromium (Cr), lead (Pb) or platinum (Pt).

4. A coating according to claim 1 , wherein the outer ceramic layer (1 ), outer metal layer (2), inner metal layer (3) and inner ceramic layer (4) each have a thickness between 5 nanometres and 100 micrometres.

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