Compound and method for the production of plastically deformed decorative products as well as plastically deformed object and use of the compound for plastic deformation

Abstract

A combination of: a substrate (1) made of aluminium, an aluminium alloy, steel, chrome-plated steel or stainless steel and a color-imparting layer system on at least one surface of the substrate (1), wherein the color-imparting layer system comprises: - an adhesive layer (2) with a layer thickness of 2 to 30 nm made of metallic chromium, molybdenum, tungsten, platinum, aluminium, titanium, zirconium, nickel or an alloy of two or more of these elements, which is applied to at least one surface of the substrate (1) by means of a PVD process, - a color-imparting layer (3) of copper, titanium, stainless steel, a Cu-Zn alloy, a Cu-Sn alloy, a Ni-Cu-Sn alloy, a non-ferromagnetic nickel alloy, CrN x , where 0.5 ≤ x ≤ 1.0, provided that the color-giving layer (3) is only made of CrN x is formed when the layer (4) described below is present, CrO y , where 0 < y < 1.5, as cermet, (Al n Cr 1-n )N x , where 0 < n < 1 and 0.5 ≤ x ≤ 1.0, or (Al n Cr 1-n )N x C z , where 0 < n < 1; 0 < x < 1.5; 0 < z < 1.0 and 0.5 < (x + z) < 1.5, which is applied to the adhesive layer (2) by means of a PVD process, - optionally an additional color-imparting layer (4) made of CrN x O y , where 0 < x < 1.0, 0 < y < 1.5 and 0.5 < y + x < 1.5, , (Al n Cr 1-n )N x , where 0 < n < 1 and 0.5 ≤ x ≤ 1.0, (Al n Cr 1-n )N x C z , where 0 < n < 1; 0 < x < 1.5; 0 < z < 1.0 and 0.5 < (x + z) < 1.5, TiO r N t , where 0 < r < 2 and 0 < t ≤ 1, titanium aluminum nitride or ZrO r N t, where 0 < r < 2 and 0 < t ≤ 1, which is applied to layer (3) by means of a PVD process, with the proviso that if layer (3) and (4) are made of (Al n Cr 1-n )N x or (Al n Cr 1-n )N x C z are formed, the ratio of Cr to Al of layer (4) differs from the ratio of Cr to Al of layer (3), and - a dielectric protective and adhesive layer (5) of Cr2O3, ZrO2, ZrO2 in which up to 20% of the Zr is replaced by Si or Ta, SiO2, SiO2 in which up to 20% of the Si is replaced by Al, Al2O3, Si3N4 or Nb2O5, which is applied to layer (3) or layer (4) by means of a PVD process or by means of a PECVD process, wherein layers (2), (3) and (5) and the optional layer (4) form the color-imparting layer system, where the total thickness of the color-imparting layer system is 400 nm or less.

Description

[0001] The present invention relates to a composite material suitable for producing a plastically deformed object, comprising a substrate and a layer system located thereon, a method for producing a plastically deformed object, the plastically deformed object, and the use of the composite material for plastic deformation. Background of the invention

[0002] For the visual appeal of many products, a combination of metallic and colored appearances is often desired, for example, in automotive parts such as body panels or interior trim, furniture components, interior elements for buildings, especially elevators, or facade elements. This can generally be achieved by applying a transparent, colored coating to a metallic substrate. Alternatively, a plastic substrate could be coated with a metallic or metallic-looking layer. However, applying metallic layers to plastic substrates can lead to adhesion problems. Furthermore, mechanical forming after applying a metallic layer to a plastic substrate is usually not possible without damaging the applied metallic layer.

[0003] When metallic substrates are used, the visible metallic surface and the texture of the substrate preclude the use of non-transparent coating systems. Therefore, in this case, transparent, color-imparting, so-called "translucent" coating systems must be used. However, these coating systems often fail to achieve the desired color saturation because the color pigments are present in low concentrations.

[0004] The requirement for a "metallic appearance" could, in principle, be met by colored anodized aluminum sheets, in which color pigments are embedded in the largely transparent anodized layer. The problem, however, is that the typically relatively thick (1-5 µm) and brittle anodized layer develops visually perceptible cracks during subsequent forming processes such as deep drawing or bending, especially in areas of greater deformation. These cracks result in an unsightly and unacceptable appearance.

[0005] CN 107 177 824 A discloses a decorative coating system for stainless steel, in which an adhesive layer is applied to the stainless steel substrate, and one or more layers of (Si:Cr)Nx are formed on top of this. The layers are applied using a PVD process, and the color of the coating system is adjustable. Plastic deformation of the composite of substrate and coating system is not disclosed.

[0006] US 2005 / 0 003 239 A1 and WO 2010 / 003 902 A1 reveal, among other things, AlCrN coatings as hard, wear-resistant coatings for tools.

[0007] CN 204 435 777 U discloses a composite consisting of an aluminum sheet, a metallic adhesive layer (in particular made of chromium), a copper layer, and an oxide protection layer. The oxide protection layer is a ceramic oxynitride, for example, an AlOxNy layer, a ZrOxNy layer, a TiOxNy layer, or a SiOxNy layer. The layers are applied by PVD. This composite is applied to a body for decorative purposes. The production of a plastically deformed object, for example, by deep drawing, from the composite disclosed in CN 204 435 777 U is not disclosed.

[0008] DE 10 2006 035 688 A1 discloses a substrate with a sequence of several layers of different materials, including a transparent or semi-transparent protective layer as a top layer, and at least one transparent or semi-transparent intermediate layer between the top layer and the substrate. DE 200 21 660 U1 discloses a composite consisting of an aluminum substrate, an intermediate layer of anodically oxidized aluminum, and an optically active multilayer system on the intermediate layer. US 2006 / 0 280 934 A1 discloses a composite consisting of a polymer substrate layer and an optically dense multilayer composite in the infrared range consisting of a metallic bonding layer, a metal layer located thereon and a protective layer.

[0009] An objective of the present invention is to provide decorative parts, in particular deep-drawn decorative parts based on aluminum, steel, or stainless steel, with a colored or color-adjustable and simultaneously metallic appearance and feel, wherein the decorative parts exhibit a very good, as uniform as possible, surface quality. Metallic appearance and feel, in this context, means in particular that the metallic nature of the aluminum, steel, or stainless steel substrate is recognizable even after the application of a coloring layer system, regardless of the surface finish of the substrate, i.e., polished, brushed, or embossed.

[0010] Such decorative products can be used, for example, as parts of motor vehicles, such as body parts or decorative parts in the interior of motor vehicles, as furniture elements, elements for the interior design of houses, especially elevators, or as facade elements.

[0011] It has now been found that by applying a color-imparting layer system to a metallic substrate using PVD processes, wherein the layers have specific compositions and are arranged in a specific sequence, and the total layer thickness of the color-imparting layer system does not exceed 400 nm, layered composites with a metallic appearance can be produced that allow mechanical forming by, for example, deep drawing and / or bending, without visible cracks appearing in the resulting plastically deformed object that would disturb its appearance, or at least that the width of the cracks is sufficiently small not to disturb the appearance.By applying the color-imparting layer system using a PVD process and maintaining a small layer thickness, the applied layer system follows the contours of the substrate, and the surface structure of the substrate is also reproduced on the surface of the color-imparting layer system, thus preserving a metallic appearance and feel. The present invention therefore provides a composite suitable for producing a plastically deformed object according to claim 1.

[0012] The present invention further provides a method for producing the composite, as well as a method for producing a plastically deformed object, in which the composite according to the invention is first produced by applying the individual layers to the substrate, and subsequently the resulting composite of substrate and color-imparting layer system is plastically deformed, in particular by deep drawing. The present invention further provides a plastically deformed object with a colored, metallic appearance, in particular a deep-drawn object, which is obtained according to the method according to the invention.is available, and in particular such a plastically deformed object in which the color-giving layer system has no cracks with a gap width greater than 2 µm, at least in areas which have a strain of the composite of 10% or less due to the deformation.

[0013] The present invention further relates to the use of the composite according to the invention for plastic deformation, in particular deep drawing or bending. Detailed description

[0014] The following figures are referenced in this description: Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. Figure 6 shows reflection spectra of various substrate and color-imparting layer systems described below. Fig. Section 7 represents the definition of radii when bending a sheet metal around a defined bending radius Rb. Fig.Figure 8 shows a light microscopic image of the surface of colored anodized aluminum, anodizing layer thickness 4 µm, substrate thickness 0.5 mm after bending; bending radius 3 mm: elongation 7.5 %; (magnification x 1000) (not according to the invention). Fig. 9, Fig. 10 to Fig. Figure 11 shows light microscopic images of the surfaces of various composites according to the invention, which were subjected to a defined strain (magnification X 1000). Fig. 12 and Fig. Figure 13 shows light microscopic images of the surface of a composite according to Example 1c on 0.8 mm thick aluminium, which was subjected to different strains by bending around a rod with a radius of 3 or 2 mm (magnification x 1000).

[0015] The present invention relates to a composite according to claim 1, which is suitable for plastic deformation and for producing a plastically deformed object. The present invention also relates to a method for producing the composite and a method for producing a plastically deformed object. In this description, preferred features for the composite are also considered preferred features for the methods and vice versa; that is, explanations and preferred embodiments apply mutatis mutandis to the composite and the methods according to the invention.

[0016] According to the invention, "plastic deformation" refers in particular to the forming techniques of deep drawing according to DIN 8584-1:2003-09. Manufacturing processes: tensile-compressive forming - Part 1: General; classification, subdivision, terms, and bending according to DIN 8586:2003-09. Manufacturing processes: bending forming - classification, subdivision, terms. Deep drawing is defined as "the tensile-compressive forming of a sheet blank (depending on the material, also a foil or plate, a cutout or section) into a hollow body or of a hollow body into a hollow body with a smaller circumference without an intended change in the sheet thickness." In the present invention, the substrate is flat, i.e., not a hollow body, so that in the present invention, the first part of this definition applies in particular.According to the invention, bending is understood to mean the forming of sheets, foils or plates by the application of a force which acts either at a point or as a distributed load uniformly and linearly over a certain length on the material.

[0017] The composite material according to the invention is suitable for producing a plastically deformed object. In a first process step in the production of the plastically deformed object, a composite material consisting of a substrate and a color-imparting layer system is produced according to the invention. Suitable materials for the substrate according to the invention include aluminum, an aluminum alloy, steel, chrome-plated steel, and stainless steel. When selecting the substrate (1), care should be taken to ensure that the surface of the material does not itself develop cracks during the forming process. For this purpose, substrates with a sufficiently high elongation at break should preferably be selected. According to the invention, substrates with an elongation at break according to DIN EN ISO 6892-1 2017, metallic materials - tensile test, of greater than 10%, preferably greater than 20%, and more preferably greater than 25% or greater than 40% are preferably suitable.The mechanical properties are usually provided by the manufacturer or can be determined by a person skilled in the art using the method described in DIN EN ISO 6892-1 (2017). However, whether a substrate is suitable for a particular deep-drawing or other forming process can also be determined by preliminary tests. In these tests, the substrate, without any coating, is subjected to the same forming or deep-drawing process that will be used for the composite material. The surface of the stretched area is then examined for cracks using a light microscope.

[0018] For the selection of the aluminium alloy, the material properties (deformation behavior, anisotropy), requirements for the end product and the mechanical strength of the workpiece can be taken into account in particular. The following aluminum alloys are generally suitable for deep drawing and can also be used according to the invention: In material conditions 0 and H 111 (here and below, material conditions refer to the conditions according to DIN EN 515:2017. Aluminum and aluminum alloys - Semi-finished products - Designations of material conditions): 1200 [AL99.0], 1050A [Al99.5], 3003 [AlMn1Cu], 5052 [AlMg2.5], 5454 [AlMg3Mn], 5754 [AlMg3], 5086 [AlMg4], 5083 [AlMg4.5Mn0.7], 5183 [AlMg4.5Mn0.7(A)], 4006 [AlSi1 Fe], 4007 [AlSi1.5Mn]. In state T4: 2017A [AlCu4MgSi(A)], 6061 [AlMg1SiCu].

[0019] Soft steels for cold forming are standardized according to DIN EN 10111:2008. Continuously hot-rolled strip and sheet made of soft steels for cold forming - Technical delivery conditions, and bear the designations DD11 to DD14. These are also mentioned as examples of substrates according to the invention: • DD11: Drawing quality - up to medium drawing depth, tight radii • DD12: Deep drawing grade - increased forming requirements, very tight radii • DD13: Special deep drawing grade - high forming requirements, multi-stage deep drawing • DD14: Special deep drawing grade containing boron - highest forming requirements, larger application range than DD13. Also common are the designations DC01 - DC07 according to DIN EN 10130:2007. Cold rolled flat products made of mild steels for cold forming - Technical delivery conditions, where DC07 has the so-called special deep drawing grade.

[0020] Stainless steels suitable for cold forming are primarily austenitic stainless steels, characterized by a high chromium (Cr) content, a high nickel (Ni) content, a low carbon (C) content, and often the addition of molybdenum (Mo). A high nickel content is particularly advantageous for deep drawing. They are characterized by a low yield strength (200-300 N / mm²). 2 ), high tensile strength (500-900 N / mm²) 2 ) and a high elongation at break > 40%. This means that the following austenitic steels, such as 1.4301 (AISI / ASTM 304; Ni 8-10.5%), 1.4306 (AISI / ASTM 304L; Ni 10-12%), 1.4303 (AISI / ASTM 305; Ni 11-13%), 1.4401 (AISI / ASTM 316; Ni 10-13%), 1.4404 (AISI / ASTM 304; Ni 10-13%), are particularly suitable for substrates according to the invention.

[0021] According to the invention, chromium-plated steel is also suitable as a substrate, in particular ECCS (Electrolytic Chromium Coated Steel) or TCCT (Trivalent Chromium Coating Technology) steel. The chromium layer on the steel is considered part of the substrate.

[0022] The substrate surface can be cleaned using a plasma process or several successive plasma processes before applying the layers of the color coating system. Preferably, chemical cleaning (degreasing and passivation) and / or electrochemical polishing can be performed prior to plasma cleaning.

[0023] According to the invention, an anodically oxidized aluminum substrate, which has an anodically produced oxide layer in the range of usually about 1 to 5 µm, is not suitable as a substrate.

[0024] However, in the case of aluminum, a natural oxide layer or a thin anodized layer produced by so-called flash anodizing with a thickness of up to 150 nm may be present. In such a case, according to the invention, the total thickness of the anodized layer, plus the color-imparting layer system, should not exceed 400 nm, or preferably 300 nm.

[0025] In the present invention, the substrate is generally a flat substrate; in particular, the substrates are preferably flat or have no curvatures during PVD coating.

[0026] For substrates or objects with complex geometries, it is difficult to obtain homogeneous layer thicknesses and compositions using vapor deposition.

[0027] Since very high demands are placed on the homogeneity of the surface, especially for objects intended for decorative purposes, it is therefore advantageous to coat flat substrates and then subsequently shape them into the desired form by plastic deformation in order to achieve a particularly homogeneous surface appearance.

[0028] Suitable substrates include sheets, plates, rolls, or films of the relevant material. Prior to coating, the substrates are preferably in the form of coils, which are long, thin sheets or films in roll form. These coils are unwound for the application of the color coating system and can be rewound into coils after the coating process is complete.

[0029] A sheet or foil with a width of 1600 mm or less, preferably 1200 mm to 1300 mm, is preferably used as the substrate. The substrate preferably has a thickness of 0.1 mm to 1.5 mm. In the case of aluminum and aluminum alloys, the substrate preferably has a thickness of 0.6 mm to 1.0 mm, more preferably 0.7 mm to 0.9 mm, and more preferably about 0.8 mm. In the case of steel, chrome-plated steel, or stainless steel as the substrate, the substrate thickness is preferably 0.1 mm to 0.6 mm, more preferably 0.2 mm to 0.5 mm. The length of the substrate, when supplied as a coil, can be several hundred meters, for example, more than 300 m. Before plastic forming, the substrate is generally cut to a suitable size.

[0030] Preferably, the substrate, initially in coil form, is unwound and first cleaned using one or more different plasma processes in an air-to-air PVD coil coating system. The layers of the color-imparting coating system are then applied in a vacuum sequence in individual deposition chambers. The substrate is preferably flat, particularly during the application of the color-imparting coating system layers.

[0031] This process enables particularly economical production of the composite, as it allows for the coating of several hundred square meters of substrate surface per hour. Non-flat substrates are typically coated using batch vacuum coating processes, which achieve much lower productivity.

[0032] Furthermore, PVD coating of already shaped objects is disadvantageous in that a coating with uniform thickness and homogeneity of composition is only possible with increased effort, especially in areas of strong deformation such as edges or corners (complex rotation systems may be required for the objects to be coated).

[0033] Therefore, coating a flat substrate, especially in an air-to-air coil coating system with subsequent shaping, is much more economical than coating an already deformed object.

[0034] According to the invention, it is further preferred to provide the substrate with a surface texture before applying the layers of the coloring system by rolling, brushing, embossing, etching, polishing, or another suitable method, or, in the case of polishing, with a smooth and / or glossy surface. Preferably, the surface is further polished electrochemically. This allows for the creation of reflective surfaces with a low diffuse reflection component. According to the invention, this surface texture or the polished surface is recognizable on the composite and the plastically deformed object even after the application of the coloring system and thus contributes to the object's appearance.In particular, the object can have a pattern by providing the substrate with regular irregularities, so that in this case the plastically deformed object is a decorative part with a colored, patterned and metallic appearance and feel.

[0035] As mentioned above, the substrate surface can be cleaned using a plasma process or several sequential plasma processes before applying the layers of the color coating system. Furthermore, chemical pretreatment (degreasing and passivation) can be performed prior to plasma cleaning. This improves the adhesion of the color coating system, allowing the resulting composite of substrate and color coating system to be deep-drawn or bent without delamination of the PVD coating system. Additionally, pretreatment, particularly a combination of chemical pretreatment and subsequent plasma treatment, is advantageous for ensuring consistent surface quality and a reproducible appearance.

[0036] In the method according to the invention, a color-imparting layer system is applied to the substrate. In the present invention, "onto" in connection with the application of layers means that the application is direct, i.e., immediate, without any further layer being located between the layer to be applied and the object to be coated, i.e., the substrate or a layer already applied. If a natural oxide layer or a flash-anodized layer is present on an aluminum substrate as described above, then the application of the adhesive layer "onto" at least one surface of the substrate according to the invention means that the adhesive layer is applied to or located on this thin layer on the surface of the substrate. If, on the other hand, the term "over" is used in this context in the present invention, a layer can be applied either directly or on an intermediate layer.

[0037] The color-imparting layer system, according to the present invention, is located on at least one surface of the substrate or is applied to it by PVD processes, or, in the case of layer (5), also by PECVD processes. According to the present invention, the color-imparting layer system can also be located on both sides of the substrate. According to the invention, one side or both sides of the substrate can cover only a portion of the substrate surface or the entire substrate surface.

[0038] In physical vapor deposition (PVD), materials to be deposited, which are in solid form, are converted into the gas phase in a coating chamber and directed onto the material to be coated, where a layer then forms (see, e.g., Gerhard Kienel, Klaus Röll: Vacuum Coating, Processes and Systems, Volume 2, Düsseldorf: VDI Verlag GmbH, 1995, Chapters 3, 4, 5 and 10, ISBN 3-18-401312-X). PVD processes that can be used according to the invention include, in particular, thermal evaporation and electron beam evaporation, including reactive electron beam evaporation and plasma-assisted electron beam evaporation, as well as sputtering processes, including reactive sputtering. Dual magnetron sputtering with rotating tube targets (so-called "rotatable targets") is particularly suitable. This process ensures high layer homogeneity across the entire substrate width, which is especially advantageous for decorative applications.Arc evaporation is generally unsuitable because this process produces so-called "droplets" that can damage the surface during deep drawing or forming. "Dropless" arc processes may be suitable in some cases.

[0039] PECVD processes (plasma-enhanced chemical vapor deposition) are also suitable for applying the top layer (5).

[0040] In the present invention, layers (2), (3), and (5), and optionally layer (4), together form the color-imparting layer system. Layer (3), and optionally layer (4), in particular contribute to the coloration, and these layers are therefore referred to in this invention as the color-imparting layers. However, the overall color impression is influenced by the entire layer system, so in this description the entire layer system consisting of layers (2), (3), and (5), as well as the optional layer (4), is referred to as the color-imparting layer system.

[0041] In the inventive method for producing the composite, a layer (2) is first applied to the substrate, i.e., directly to it, using a PVD process. The layer (2) serves in particular as an adhesive layer for the subsequent layer (3) described later and can also determine the color of the color-imparting layer system.

[0042] According to the invention, the thickness of the adhesive layer (2) is 2 to 30 nm, more preferably 5 to 30 nm or 5 to 20 nm.

[0043] According to the invention, the material for the layer (2) is formed from the metals chromium, molybdenum, tungsten, aluminum, titanium, zirconium, nickel, or an alloy of two or more of these elements. For example, WTi10, a tungsten alloy with 10 wt.% titanium, is suitable as an alloy. Preferred materials for the adhesive layer (2) under these materials are chromium, titanium, molybdenum, aluminum, or nickel, with chromium and titanium being particularly suitable for aluminum and aluminum alloy substrates.

[0044] According to the invention, sputtering processes are preferably used as PVD methods for depositing the layer (2), since these ensure particularly good layer adhesion to the substrate due to the high particle energies. The preferred PVD method for layer (2) is magnetron sputtering, with dual magnetron sputtering being particularly preferred.

[0045] In the inventive method, layer (3) is applied to layer (2). Layer (3), optionally together with the optional layer (4), is the actual color-imparting layer of the color-imparting layer system and substantially determines the color of the color-imparting layer system.

[0046] According to the invention, sputtering processes are preferably used as PVD methods for depositing layers (3) and (4). Magnetron sputtering, and especially dual magnetron sputtering, is the preferred PVD method for layers (3) and (4). Reactive sputtering, and particularly preferably reactive dual magnetron sputtering, is suitable for depositing the metal oxynitride compounds. Depending on the desired composition, a defined quantity of oxygen, nitrogen, or a carbon-containing gas (e.g., CH4, C2H6, C2H2, or CO2) is introduced into the coating chamber. The layer composition is preferably controlled by a lambda probe in reactive magnetron sputtering with oxygen, or by a plasma emission monitoring (PEM) system when using a mixture of oxygen, nitrogen, and / or a carbon-containing gas.

[0047] If the material of layer (3) and / or (4) is a composition containing chromium and aluminum, alloy targets can be used where the ratio between Cr and Al is predetermined. However, this ratio can change over time because the two materials have different sputtering yields. Therefore, a co-sputtering technique is preferably used, in which a dual magnetron system is equipped with one chromium target and one aluminum target. These are preferably rotating targets. The ratio between Cr and Al in the layer is adjusted by controlling the sputtering power of the two targets, taking into account the different sputtering yields of Cr and Al.

[0048] According to the invention, the material for layer (3) is made of copper, titanium, stainless steel, a Cu-Zn alloy, a Cu-Sn alloy, a Ni-Cu-Sn alloy, a non-ferromagnetic nickel alloy,

[0049] Chromium nitride (CrN x , wherein 0.5 ≤ x ≤ 1.0, preferably 0.90 ≤ x ≤ 1.0, more preferably 0.95 ≤ x ≤ 1.0), provided that in the present invention this can only be used for layer (3) if the optional layer (4) is also present.

[0050] Chromium oxide (CrO₂) y , where 0 < y < 1.5, preferably, 1 < y < 1.4, further preferably 1 < y < 1.3), Chromium aluminum nitride ((Al n Cr 1-n )N x , wherein 0 < n < 1, preferably 0 < n < 0.95, more preferably 0.20 ≤ n < 0.70, further preferably 0.25 ≤ n ≤ 0.70, and 0.5 ≤ x ≤ 1.0, preferably 0.95 ≤ x ≤ 1.0), or chromium aluminum carbonitride selected.

[0051] Chromium aluminum carbonitride can be known as (Al n Cr 1-n )Nx C z be formulated where 0 <n<1, bevorzugt 0<n<0,95, bevorzugter 0,20≤n<0,70; 0 < x < 1,5, 0< z < 1,0; und 0,5 < (x+z) < 1,5.

[0052] In the case of chromium aluminum nitride, a stoichiometric ratio between the metals and the nitrogen is targeted, although slight deviations from the exact stoichiometry may occur due to production processes.

[0053] In the case of chromium aluminum carbonitride, preferably up to 95 atomic percent of the chromium in the corresponding chromium carbonitride can be replaced by aluminum, preferably up to 70 atomic percent.

[0054] According to the invention, a copper-zinc alloy with a zinc content of up to 40 wt.%, such as brass, is particularly suitable as a copper-zinc alloy.

[0055] According to the invention, a copper-tin alloy with a tin content of up to 20 wt.%, such as bronze, is particularly suitable as a copper-tin alloy. According to the invention, an alloy with approximately 65 wt.% nickel, 33 wt.% copper and 2 wt.% iron, also known as Monel, is particularly suitable as a nickel-copper-iron alloy.

[0056] Suitable non-ferromagnetic nickel alloys are preferably nickel alloys with vanadium (NiV), chromium (NiCr), aluminum (NiAl), or copper (NiCuFe) as alloying partners. Particularly preferred are NiCr 80:20%, NiV 93:7%, NiAl 90:10%, and NiCuFe 65:33:7% (each in weight percent).

[0057] Chromium oxide, if present, exists as cermet in the coloring layer (3). The compositions chromium aluminum nitride, chromium oxynitride (in the case of layer (4)), chromium carbonitride (in the case of layer (4)), chromium oxycarbonitride (in the case of layer (4)), or chromium aluminum carbonitride can, in embodiments of the invention, which may be preferred, be present in the form of cermets. In the case of cermets (ceramic metals), metallic particles or particles of a material with metallic characteristics (such as CrN) on the order of magnitude below the wavelength of light are embedded in a dielectric matrix, which consists, for example, of Cr₂O₃ or AlN.

[0058] In other embodiments of the invention, which may also be preferred, the material for the layer (3) is pure metals or metal alloys.

[0059] When using pure metals or metal alloys for layer (3) and / or the optional layer (4), the perceived color is primarily determined by the intrinsic optical properties of these materials. In this case, the intrinsic color of the material used can be achieved, for example, by applying a thin layer of titanium, giving the object the appearance of being made of pure titanium. In this case, it is advantageous to choose a layer thickness at which layer (3) is optically dense. This means that no light in the visible wavelength range (380–780 nm) penetrates layer (3) and thus does not reach the adhesive layer (2) or, if applicable, the substrate, so that no interference effects occur that could distort the intrinsic color of the material in layer (3).

[0060] In the case of using cermets for layer (3) and / or the optional layer (4), an advantage lies in the fact that their optical properties can be adjusted over a wide range, since, depending on the composition, either the metallic or dielectric properties tend to dominate. The optical properties of these materials can be described by an Effective Media Theory (ETM). The Maxwell-Garnett theory for interstitial microstructures and the Bruggeman theory for interpenetration microstructures have proven particularly useful (see, e.g., Jeffry Gordon: Solar Energy, The State of the Art, In: ISES Position Papers, 2001, ISES, pages 123–127, ISBN 1902916239, 9781902916231).

[0061] Cr-based cermets are particularly suitable for use as cermets for layer (3) and / or the optional layer (4), as they exhibit high temperature and corrosion stability.

[0062] In the aforementioned compositions chromium oxide, chromium oxynitride, chromium carbonitride or chromium oxycarbonitride, chromium oxide acts as a dielectric matrix in which metallic particles of pure chromium, or CrN or CrC, which possess a metallic character, are embedded.

[0063] Chromium aluminum nitrides in the form of cermets are also formally compositions of the formula (Al n Cr 1-n )N x However, for cermets, the notation (Cr:Al)N is frequently used, where the ratio of the metals to each other can vary and be indicated by subscripts. In the case of chromium aluminum nitride cermets, AlN acts as a dielectric matrix into which particles of CrN with metallic properties are embedded.

[0064] Thus, it is possible to produce layer (3) as a predominantly dielectric layer with high transparency or as a metallic layer with high reflection and absorption. The intermediate region between metallic and dielectric properties is of particular interest for the invention. Here, partially transparent absorbing layers can be produced. Since at least some of the light can penetrate layer (3) in these layers and interact with layer (2) and the substrate (1), interference effects occur. By appropriately selecting the thickness of layer (3), the interference minimum can be controlled to achieve a specific color impression. Since the absorption in the layer can also be adjusted by modifying the composition of the cermet, the color depth is also adjustable.

[0065] Preferred materials for the layer (3) according to the invention are aluminium, copper, non-ferromagnetic nickel alloys, in particular nickel-vanadium alloys, preferably with about 6 to 10 wt.% V, chromium oxide, in particular in the form of a cermet of metallic chromium in a ceramic Cr2O3 matrix, and chromium aluminum nitrides, in particular in the form of a cermet in which particles of CrN with metallic properties are embedded in AlN as a dielectric matrix.

[0066] The layer (3) preferably has a layer thickness of 5 to 200 nm, more preferably of 10 to 150 nm, further preferably of 10 to 100 nm or 15 to 60 nm or 20 to 50 nm.

[0067] Optionally, a further color-imparting layer (4) made of chromium oxynitride, chromium aluminum nitride, chromium aluminum carbonitride, titanium oxynitride, titanium aluminum nitride, or zirconium oxynitride is applied to layer (3), i.e., between layer (3) and the protective and adhesive layer (5), by means of a PVD process. Only if a color-imparting layer (4) is present can CrN be selected as the material for layer (3) in the present invention.

[0068] Furthermore, for layer (4) if layer (3) and (4) are formed from chromium aluminum nitride or chromium aluminum carbonitride, the ratio of Cr to Al of layer (4) differs from the ratio of Cr to Al of layer (3).

[0069] Chromium oxynitride can be known as CrN x O y can be formulated where 0 < x < 1.0, 0 < y < 1.5 and 0.5 < y + x < 1.5.

[0070] Chromium carbonitride can be known as CrN x C zcan be formulated where 0 < x < 1.5, 0 < z < 1.0; and 0.5 < (x + z) < 1.5.

[0071] Chromium oxycarbonitride can be known as CrN x O y C z can be formulated where 0 < x < 1.0; 0 < y < 1.5; 0 < z < 1.0 and 0.5 < (x+y+z) < 1.5).

[0072] Titanium oxynitride and zirconium oxynitride can be replaced by TiO r N t and ZrO r N t represented where r is in the range 0 < r < 2 and t is in the range 0 < t ≤ 1.

[0073] In the case of titanium aluminum nitride, up to 75 atomic percent of the titanium can be replaced by Al, preferably up to 50 atomic percent.

[0074] Apart from that, chromium oxynitride, chromium aluminum nitride, chromium aluminum carbonitride, and their preferred embodiments are defined as for layer (3). Like layer (3), layer (4) can also be a cermet, as described above.

[0075] Preferred materials for layer (4) are chromium aluminum nitride, chromium aluminum carbonitride, chromium oxynitride, titanium oxynitride, titanium aluminum nitride and zirconium oxynitride.

[0076] Applying the optional color-imparting layer (4) in the form of a cermet to layer (3) is particularly advantageous, for example, when very dark colors, or a gray or black color impression, are desired. For this purpose, a so-called gradient in the optical properties can be set. This means that layer (3) is then more metallic and layer (4) more dielectric.

[0077] A preferred combination exists when layer (3) is formed from chromium nitride and layer (4) is formed from chromium oxynitride.

[0078] The layer (4) preferably has a layer thickness of 5 to 200 nm, more preferably of 10 to 150 nm, further preferably of 10 to 100 nm or 15 to 60 nm or 20 to 50 nm.

[0079] A dielectric protective and adhesive layer (5) made of Cr₂O₃, ZrO₂, ZrO₂ in which up to 20 atomic percent of the Zr is replaced by Si or Ta (“ZrSiO₂”, “ZrTaO₂”), SiO₂, SiO₂ in which up to 20 atomic percent of the Si is replaced by Al (“SiAIO₂”), Al₂O₃, Si₃N₄, or Nb₂O₅ is applied to layer (3), or to layer (4) if it is present, by means of a PVD process or by means of PECVD. SiAlO₂ with 10 atomic percent aluminum, Cr₂O₃, ZrO₂, and Nb₂O₅ are preferred for layer (5).

[0080] Due to the manufacturing process, the materials for layer (5) may also be slightly substoichiometric or deviate from the ideal stoichiometry. However, stoichiometry is the goal.

[0081] Layer (5) is also part of the color-giving layer system and, in addition to a protective function, also has the property that subsequently optionally applied clear coat layers or sol-gel layers adhere well to it.

[0082] The protective and adhesive layer (5) is also optically active, meaning it can also contribute to the color of the overall layer system. The materials used here primarily possess dielectric properties, meaning they are transparent. By precisely adjusting the layer thickness, anti-reflection coatings (anti-reflective coatings) of the underlying layers can be achieved. This allows the color depth of the overall layer system to be adjusted.

[0083] The layer (5) is preferably applied by reactive sputtering or by electron beam evaporation, preferably reactive electron beam evaporation, or a PECVD method (plasma enhanced chemical vapor deposition).

[0084] The thickness of the layer (5) is preferably from 5 to 200 nm, more preferably from 10 to 100 nm, further preferably from 10 to 80 nm or 20 to 50 nm.

[0085] Preferred color-imparting layer systems are shown in Table 1 below, where the preferred areas / indices mentioned above are used for each material: Nr . function preferred Population layer thickness (nm) Proceedings 5 Protective and adhesive layer Cr2O3, ZrO2, SiAlO2, Nb2O5 10-100,10-80,20-50 Reactive Magnetron Sputtering, PECVD 4 optional color-imparting layer Chromium aluminum nitride, in particular as cermet, chromium aluminum carbonitride, chromium oxynitride (in particular as cermet; furthermore in particular in combination with chromium nitride as layer(3)), titanium oxynitride, titanium aluminum nitride or zirconium oxynitride 10-150,10-100,15-50 Reactive Magnetron Sputtering 3 coloring layer Cu, Ti, NiV7, chromium nitride in the presence of layer (4), chromium oxide, especially as cermet, chromium aluminum nitride, especially as cermet, 10-150,10-100,20-60 Magnetron sputtering, for compound reactive magnetron sputtering 2 Adhesive layer Cr, Ti, Mo 5-30,5-20 Magnetron sputtering 1 substrate Al as in Al 1080, Al alloys; such as Al8014, stainless steel, such as 1.4301, , 1.4404, ECCS or TCCT (Trivalent Chromium Coating Technology) steel

[0086] A key aspect of the present invention is that the total thickness of all layers of the color-imparting coating system is 400 nm or less, preferably 300 nm or less. Preferred ranges for the total thickness are 30 to 400 nm, more preferably 40 nm to 350 nm, and even more preferably 50 nm to 300 nm or 60 to 250 nm. The total thickness refers to the sum of the thicknesses of layers (2), (3), and (5). In the case of the presence of layer (4), the total thickness refers to the sum of the thicknesses of layers (2), (3), (4), and (5). If an aluminum or aluminum alloy substrate has a natural aluminum oxide layer or a thin aluminum oxide layer produced by flash anodizing, the above thickness ranges apply to the total thickness of the color-imparting coating system, including this oxide layer on the substrate.If chrome-plated steel is used as the substrate, the chromium layer on the steel is considered part of the substrate, and the adhesive layer (2) is applied to it. If the total thickness of the coloring layer system of the present invention is 400 nm or less, deep drawing or bending results in a plastically deformed or formed object that has no cracks visible to the naked eye. A decorative part can thus be obtained that is colored, has a metallic appearance and feel, since the surface structure of the metallic substrate is visible or the surface structure of the substrate is reproduced on the surface by the layers of the coloring layer system, and its appearance is not disturbed by the presence of visible cracks.

[0087] According to the invention, the layer thicknesses of the produced composite can be precisely determined using transmission electron microscopy. During the production of the composite, the layer thickness of the individual layers can be determined and controlled, for example, by means of ellipsometry, whereby an ellipsometric measurement can be performed after each vacuum chamber when using a coil coating system. Alternatively or additionally, the conditions under which a specific layer thickness is achieved can be determined in preliminary tests for a given coating system.

[0088] The color of the color-giving layer system can be varied by varying the composition and layer thickness of the layers.

[0089] The color of the PVD coating according to the invention is determined by several factors: the intrinsic optical properties of the materials used, interferences, multiple reflections and multiple absorptions in and at the interfaces of the individual layers of the PVD layer system.

[0090] The color impression of the overall layer system is mainly determined by the optical properties of the material chosen for layer (3) and the material of the optional layer (4).

[0091] To illustrate this, the reflection spectra of various materials and layer systems are shown in the Fig. 1 shown.

[0092] First, the reflection spectrum of a pure chromium nitride layer (55 nm thick), forming layer (3), is plotted on an aluminum substrate (1) with a Cr adhesion layer (2). Since chromium nitride has a metallic character, the reflection is very high.

[0093] If the chromium in this layer is successively replaced by aluminum, a cermet can form (in Fig. 1 is, among other things, a (chromaluminium nitride layer with 20 atomic-% aluminum nitride and with 40 atomic-% aluminum nitride applied, in Fig. 1 by Cr 0,80 Al 0,20 N and Cr 0,60 Al 0,40 (designated N), so that with increasing aluminum content, the reflection decreases because the layer becomes more absorbent. If an additional 20 nm thick layer (5) of Cr₂O₃ is applied, the reflection decreases again due to the antireflection. If the chromium aluminum nitride layer (3) with 40 atomic percent AlN is then covered by a chromium aluminum nitride layer (3) with 35 atomic percent aluminum nitride content (in Fig. 1 as Cr 0,65 Al 0,35 N) and a chromium aluminum nitride layer (4) with 45 atomic-% aluminum nitride content (in Fig. 1 as Cr 0,55 Al 0,45If N is replaced, the reflection in the visible wavelength range can be reduced even further.

[0094] The reflection spectrum of the entire layer system can be calculated using a matrix method derived from the Fresnel equations; see, for example, BE Hecht: Optics. 3rd edition. Munich, Vienna: Oldenbourg Wissenschaftsverlag 2001, ISBN 3-486-24917-7; pages 626 to 635. From this, the color values ​​of the entire layer system can be calculated, for example, according to the CIE L*a*b* system.

[0095] Due to the application using PVD technology or, if applicable, PECVD in the case of layer (5), the overall layer thickness, and the material combination of the coloring layers, the layers of the coloring layer system exhibit excellent adhesion. The composite is therefore ideally suited for mechanical forming, for example, by deep drawing or bending, as the layers do not detach during mechanical forming.

[0096] After the color-imparting layer system has been applied to obtain the bond between the substrate and the color-imparting layer system (step a), in a second step of the process for producing the plastically deformed object (step b) a plastic deformation of the bond takes place to obtain the plastically deformed object.

[0097] As already mentioned, "plastic deformation" according to the invention refers in particular to the forming techniques of deep drawing according to DIN 8584-1:2003-09. Manufacturing processes tensile-compressive forming - Part 1: General; classification, subdivision, terms, and bending according to DIN 8586:2003-09. Manufacturing processes bending forming - classification, subdivision, terms.

[0098] After the application of the color-imparting layer system, openings or holes can be formed in the composite in embodiments of the invention, preferably by punching, drilling, milling, laser cutting, or other suitable methods. The formation of holes can preferably take place before plastic deformation, as this is easier with undeformed products, but is not limited to this; i.e., the formation of holes can also take place after plastic deformation.

[0099] Particularly due to the thickness of the color-imparting layer system, but also due to the PVD coating process and the choice of material, a formed object can be obtained after deep drawing or bending of the composite, especially when the elongation is 10% or less, which exhibits no cracks in the PVD layer system with a gap width greater than 2 µm. Thus, if a composite obtained according to the inventive method is formed by deep drawing or bending, a colored object without defects visible to the naked eye and with a metallic appearance can be obtained. According to the invention, this is achieved at least up to an elongation of the composite of up to 10%, preferably at an elongation of 2% to 10%, more preferably 4% to 10% or 5% to 8%, and in some embodiments of the invention has also been achieved at an elongation of 20%.According to the invention, a metallic appearance and feel are achieved without the use of pigments, such as those used in metallic lacquers or color anodized coatings. The appearance also differs from that of objects coated with metallic lacquers, since in the present invention the surface structure of the metallic substrate is still recognizable or is transferred to the surface by the color-imparting coating system. In particular, lacquered surfaces do not have a metallic feel.

[0100] The aforementioned stretching of the composite refers to the unavoidable material strain that occurs during the forming process. If a composite according to the invention is subjected to a forming process that causes a material strain of 10% or less, a plastically deformed object is obtained by deep drawing or bending that exhibits no cracks in the PVD layer system with a width greater than 2 µm.

[0101] To test the suitability of a composite for producing a plastically deformed object without cracks of 2 µm or less, the composite can be subjected to a defined strain. The principle for generating such a defined strain is described in Fig. Figure 7 illustrates this. To generate such a defined strain, the composite is bent around a defined bending radius Rb. Rb can be achieved using a metal rod. Ra in Fig.7 denotes the outer diameter, i.e., the distance of the outer surface of the bent composite from the center of the metal rod. Fig. Figure 7 represents the radius Rm, which denotes the distance from the center of the metal rod to the center of the composite. D indicates the thickness of the composite.

[0102] Since bending stretches the outer surface of the material (compresses the inner surface) and the material in the middle remains unchanged, the relative elongation is given by the ratio of the length of the outer circumference Ua to the circumference of the center line Um as follows: Elongation[%]=((Ua / Um)−1)∗100=((2πRa / 2πRm)−1)∗100=[((Rb+D) / (Rb+D / 2))−1]*100

[0103] The stretched composite (substrate with the PVD layer system on the outside) is examined with a light microscope (1000x magnification) and the crack width is determined.

[0104] It was found that with a thickness of 400 nm or less of the colorant layer system and a strain of 10% or less, no cracks with a gap width greater than 2 µm occur. Reducing the thickness of the colorant layer system to 300 nm or less significantly reduces the crack width to well below 1 µm, which is preferable. The crack width thus depends substantially on the thickness of the colorant layer system. It was further observed that the number of cracks per unit area, or the mean distance between cracks, increases with the degree of strain (see [reference]). Fig. 9-11, microscopic images of a composite of aluminum substrate and a PVD coating system with a total thickness of 340 nm, subjected to different strains). For color anodized aluminum sheets with an aluminum oxide layer thickness in the µm range, the crack width under comparable strain conditions is significantly greater than 2 µm (see Fig. 8).

[0105] The present invention also relates to a plastically deformed or reshaped object obtainable or obtained according to the inventive method. In the object according to the invention, the surface structure of the substrate is recognizable, and the color-imparting layer system exhibits no cracks with a gap width greater than 2 µm, at least in areas exhibiting a material strain, as defined above, of 10% or less, in particular a material strain of 2% to 10%, preferably 4% to 10% or 5% to 8%. A plastically deformed object according to the invention can therefore exhibit no cracks with a gap width of 2 µm or more overall, or it exhibits no cracks with a width of 2 µm or more, at least in areas where the material has undergone a strain of 10% or less.This also includes items that have undergone an elongation of more than 10% at one or more points during forming and may also show visible cracks at the points of greater material elongation.

[0106] The plastically deformed object according to the invention may preferably be a decorative element of a motor vehicle, in particular in the interior of motor vehicles, a furniture element, an element for the interior design of houses, in particular elevators, or a facade element.

[0107] The present invention further relates to the use of the above-described composite of the substrate (1) and the color-imparting layer system for the production of a plastically deformed object.

[0108] The color-imparting layer system on the composite remains UV, temperature and humidity stable.

[0109] For example, the following tests are performed: • Temperature test at 150°C for 100 hours in a dry atmosphere, • UV test at 0.53 W / m² 2 and 65°C for 100 hours, in a dry atmosphere, • Steam heat test at 85% rH / 85°C for 1000 hours, the change ΔE of the color values ​​after these tests is less than 5. The adhesion is also good after these tests. Examples

[0110] The invention will be explained in more detail below using specific exemplary embodiments.

[0111] The CIE L*a*b* color space is used to describe the colors produced with the examples. It is standardized in EN ISO 11664-4:2008 “Colorimetry -- Part 4: CIE 1976 L*a*b* Colour space”. D65 light at a viewing angle of 10° is used as the standard light source. Example 1: Grey-black coating on an aluminum substrate

[0112] The substrate used is aluminum strip made from an 8014 alloy in condition H21. The mechanical parameters are as follows: tensile strength Rm 100–115 MPa, yield strength Rp0.2 = 50–70 MPa, elongation at break A50 > 25%. This material, with its high tensile strength and high elongation at break combined with a low yield strength, thus fulfills the requirements for good machinability in deep drawing. An aluminum strip with a thickness of 0.8 mm and a width of 1250 mm was used. The aluminum surface was brushed after rolling to achieve a brushed finish.

[0113] The surface of this strip substrate was then treated in a continuous wet-chemical process, during which the substrate passed through various baths: First, the strip substrate went through a cleaning bath in which surface contaminants from the rolling process were removed by etching. Subsequently, the strip passed through a bath in which it was electrochemically polished. The intensity of the electrochemical process was controlled to achieve the desired surface structure. Electrochemical polishing is also advantageous for brushed or embossed surfaces to achieve the desired gloss level.

[0114] The pre-treated substrate was then coated using an air-to-air PVD coil coating system.

[0115] After the belt passed through vacuum locks into the vacuum, the substrate surface was cleaned using a plasma process. The belt then passed through various coating stations where the individual layers of the coating system were deposited using different PVD processes described above. The thickness of each layer was measured and controlled by ellipsometry. The optical properties of the entire coating system at the end of the coating process were measured using spectrometers equipped with integrating spheres, and the CIE color values ​​L*a*b* were determined.

[0116] As described, very dark surfaces are difficult to achieve with translucent coating systems. When using black coatings, the surface gloss of the metal is lost, and black anodized aluminum sheets can only be formed to a limited extent.

[0117] The following dark grey-black surface coatings have been implemented, which exhibit a metallic sheen. Example 1a)

[0118] A PVD layer system was created consisting of an adhesive layer (2) made of Cr, a coloring layer (3) made of CrN, and another coloring layer (4) made of formally CrO. 1,2 N 0,1 (presented as cermet with 26 atomic percent metallic Cr and 13 atomic percent CrN in Cr₂O₃) and a protective layer (5) of Cr₂O₃. The layer thicknesses and compositions of the individual layers are listed in Table 2. The color values ​​produced by this layer system are also found there. In the Fig. Figure 2 shows the reflection spectrum of this layer system.

[0119] This coating system exhibits excellent adhesion in the cross-hatch test according to DIN EN ISO 2409 2019. Paints and varnishes - Cross-cut test / ASTM D 3359 2017. Standard Test Methods for Measuring Adhesion by Tape Test.

[0120] The adhesion of clear coats to this coating system is excellent.

[0121] The PVD coating system exhibits good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 1b)

[0122] A PVD layer system was created consisting of an adhesive layer (2) made of Cr, a color-imparting layer (3) made of (Cr 0,60 Al 0,40 )N (present here as cermet with 60 atomic percent CrN and 40 atomic percent AIN) and a protective layer (5) of Cr2O3. The layer thicknesses and the compositions of the individual layers are listed in Table 2. The color values ​​of this layer system are also found there. In the Fig.Figure 2 shows the reflection spectrum of this layer system. Compared to the layer system from embodiment 1a), which still exhibits a slight blue component, layer system 1b) was significantly more color-neutral. Both the a* and b* values ​​are less than 1.

[0123] This coating system exhibited excellent adhesion in the cross-hatch test according to DIN EN ISO 2409 2019. Paints and varnishes - Cross-cut test / ASTM D 3359 2017. Standard Test Methods for Measuring Adhesion by Tape Test. The adhesion of clear coats to this coating system was excellent.

[0124] The PVD coating system exhibits good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 1c)

[0125] A PVD layer system was created consisting of an adhesive layer (2) made of Cr, a color-imparting layer (3) made of (Cr 0,65 Al 0,35)N (present as cermet with 65 atom% CrN and 35 atom% AlN), a further color-giving layer (4) of (Cr 0,55 Al 0,45 )N (present here as cermet with 55 atomic percent CrN and 45 atomic percent AIN) and a protective layer (5) of Cr2O3. The layer thicknesses and the compositions of the individual layers are listed in Table 2. The color values ​​of this layer system are also found there. In the Fig. Figure 2 shows the reflection spectrum of this layer system. Compared to embodiment 1b, this layer system achieved even lower reflection in the visible wavelength range.

[0126] This coating system demonstrated excellent adhesion in the cross-hatch test according to DIN EN ISO 2409 2019. Paints and varnishes - Cross-cut test / ASTM D 3359 2017. Standard Test Methods for Measuring Adhesion by Tape Test. The adhesion of clear coats to this coating system is excellent.

[0127] The PVD coating system exhibited good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 1d)

[0128] A PVD layer system consisting of an adhesive layer (2) made of Cr, a color-imparting layer (3) made of (Cr) was developed. 0,72 Al 0,28 )N (present as cermet with 72 atom% CrN and 28 atom% AlN), a further color-giving layer (4) of (Cr 0,39 Al 0,61 )N (present here as cermet with 39 atomic percent CrN and 61 atomic percent AIN) and a protective layer (5) of ZrO2. The layer thicknesses and the compositions of the individual layers are listed in Table 2. The color values ​​of this layer system are also found there. In the Fig.Figure 2 shows the reflection spectrum of this layer system. Compared to embodiments 1b and 1c, this layer system achieves even lower reflection in the visible wavelength range.

[0129] This coating system demonstrated excellent adhesion in the cross-hatch test according to DIN EN ISO 2409 2019. Paints and varnishes - Cross-cut test / ASTM D 3359 2017. Standard Test Methods for Measuring Adhesion by Tape Test. The adhesion of clear coats to this coating system is excellent.

[0130] The PVD coating system exhibits good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 1e)

[0131] A PVD layer system consisting of an adhesive layer (2) made of Cr, a color-imparting layer (3) made of (Cr) was developed. 0,57 Al 0,43)N (present as cermet with 57 atom% CrN and 43 atom% AlN), a further color-giving layer (4) of (Cr 0,35 Al 0,65 )N (present here as cermet with 35 atomic percent CrN and 65 atomic percent AIN) and a protective layer (5) of SiO2. The layer thicknesses and the compositions of the individual layers are listed in Table 2. The color values ​​of this layer system are also found there. In the Fig. Figure 2 shows the reflection spectrum of this layer system. Compared to embodiments 1b, 1c and 1d, this layer system achieved even lower reflection in the visible wavelength range.

[0132] This coating system demonstrated excellent adhesion in the cross-hatch test according to DIN EN ISO 2409 2019. Paints and varnishes - Cross-cut test / ASTM D 3359 2017. Standard Test Methods for Measuring Adhesion by Tape Test. The adhesion of clear coats to this coating system is excellent.

[0133] The PVD coating system exhibited good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 2: Colored layer systems on an aluminum substrate

[0134] The substrate used was aluminum strip made from an Al1080 alloy in condition O or H111. The mechanical parameters are as follows: tensile strength Rm 65–90 MPa, yield strength Rp0.2 > 20 MPa, elongation at break A50 > 20%. This material, with its high tensile strength and high elongation at break combined with a low yield strength, thus fulfills the requirements for good machinability in deep drawing. The aluminum strip had a thickness of 0.7 mm and a width of 1250 mm.

[0135] The surface of this strip substrate was treated in a continuous wet chemical process, during which the substrate passed through various baths: First, the strip substrate passed through a cleaning bath in which surface contaminants from the rolling process were removed. Subsequently, the strip passed through a bath in which it was electrochemically polished. The intensity of the electrochemical process was controlled to achieve the desired surface structure.

[0136] The advantage of the Al 1080 material used lies in its 99.8% purity, which means it contains very few impurities. Impurities can cause pitting corrosion during electrochemical brightening. Due to its low impurity content, Al 1080 is particularly well-suited for electrochemical brightening and polishing.

[0137] By using mirror-polished rolled material, a mirror-smooth surface with high directional reflection and a diffuse reflection of less than 2% was achieved by means of electrochemical brightening, which meets special aesthetic requirements.

[0138] However, surfaces such as "mill finish" or other structured surfaces can also be used, whereby the gloss level can be adjusted by means of electrochemical polishing. Exemplary embodiment 2a)-1 to 2a)-4

[0139] A PVD coating system was created consisting of an adhesive layer (2) made of Cr, a color-imparting layer (3) made of chromium oxide (cermet with 20 atomic% metallic Cr in Cr2O3, formally CrO). 1,2 ) and a protective layer (5) of ZrO2. By varying the thickness of the CrO 1,2 -Layer (3) can produce different color impressions (see Table 2).

[0140] In the Fig.Figure 3 is the reflection spectrum of this layer system with different CrO layer thicknesses. 1,2 -Layer (3) applied.

[0141] This coating system demonstrated excellent adhesion in the cross-hatch test according to DIN EN ISO 2409 2019. Paints and varnishes - Cross-cut test / ASTM D 3359 2017. Standard Test Methods for Measuring Adhesion by Tape Test. The adhesion of clear coats to this coating system is excellent.

[0142] The PVD coating system exhibited good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 2b)

[0143] A PVD coating system was formed consisting of an adhesive layer (2) made of titanium, a color-imparting layer (3) made of NiV7, and a protective layer (5) made of ZrO2. This coating system can produce a golden color impression (see Table 2).

[0144] In the Fig.Figure 3 shows the reflection spectrum of this layer system.

[0145] This coating system demonstrated excellent adhesion in the cross-hatch test according to ISO 2409 (2019) / ASTM D 3359 (2017). The adhesion of clear coats to this coating system is excellent.

[0146] The PVD coating system exhibits good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Exemplary embodiment 2c)-1 to 2c)-3

[0147] According to the invention, a PVD layer system consisting of an adhesive layer (2) made of Cr, a color-imparting layer (3) made of (Cr) 0,3 Al 0,7 )N (present here as cermet with 30 atomic percent CrN and 70 atomic percent AIN) and a protective layer (5) of Cr2O3 are formed. By varying the thickness of the (Cr 0,3 Al 0,7 )N layer (3) can produce particularly intense red, blue and green color impressions (see Table 2).

[0148] In the Fig. 4 is the reflection spectrum of this layer system with different layer thicknesses of (Cr 0,3 Al 0,7 )N layer (3) applied.

[0149] This coating system demonstrated excellent adhesion in the cross-hatch test according to DIN EN ISO 2409:2019 (Paints and varnishes - Cross-cut test / ASTM D 3359:2017, Standard Test Methods for Measuring Adhesion by Tape Test). The adhesion of clear coats to this coating system is also excellent.

[0150] The PVD coating system exhibited good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 2d)

[0151] A PVD coating system was created consisting of an adhesive layer (2) made of Cr, a color-imparting layer (3) made of Cu and a protective layer (5) made of SiAl. 0,1 O2 (SiO2, in which 10 atomic % of the Si is replaced by Al) is formed.

[0152] In the Fig. 5 is the reflection spectrum of this layer system with and without SiAl 0,1 O2 protective layer applied.

[0153] This coating system demonstrated excellent adhesion in the cross-hatch test according to DIN EN ISO 2409:2019 (Paints and varnishes - Cross-cut test / ASTM D 3359:2017, Standard Test Methods for Measuring Adhesion by Tape Test). The adhesion of clear coats to this coating system is also excellent.

[0154] The PVD coating system exhibits good stability in the UV, temperature, and humidity tests listed above. The change ΔE of the color values ​​after these tests is less than 5. Example 3: grey-black layer system on stainless steel substrate

[0155] Stainless steel strip made from a 1.4404 (AISI / ASTM 316L) alloy was used as the substrate. The mechanical parameters are as follows: tensile strength Rm = 520–680 MPa, yield strength Rp0.2 = 220–240 MPa, elongation at break A80 > 40%. This material, with its high tensile strength and high elongation at break combined with a low yield strength, thus fulfills the requirements for good machinability in deep drawing and forming. The surface finish is 2R (cold-rolled, bright annealed – smooth and reflective).

[0156] A PVD layer system was created consisting of an adhesive layer (2) made of Mo, a coloring layer (3) made of CrN, and another coloring layer (4) made of CrO. 1,1 N 0,1 (Cermet with 28 atomic percent Cr and 5 atomic percent CrN in Cr2O3) and a protective layer (5) of Cr2O3 are formed. The layer thicknesses and compositions of the individual layers are listed in Table 2. The color values ​​produced by this layer system are also found there. In the Fig.Figure 6 shows the reflection spectrum of this layer system.

[0157] Details and results of the experiments are summarized in Table 2. Example D65 Substrate (1) Adhesive layer (2) Layer (3) Optional layer (4) Protective and adhesive layer (5) Reflect spectral Nr. Color L* a* b* material Thickness (nm) material Thickness (nm) material Thickness (nm) material Thickness (nm) figure 1a grey-blue 36,7 0,7 -2,9 Al 8014 H21 non-anodized Cr 5 CrN 45 CrO 4,2 N 0,1 (Cermet, 26 Atom-% Cr, 13 Atom-%CrN) 40 Cr2O3 45 2 1b grey-blue 43,8 -0,6 0,5 Al 8014 H21 non-anodized Cr 5 (Cr 0,60 In the 0,40 )N (Cermet) 55 Cr2O3 20 2 1c anthracite 40,0 -0,2 -0,3 Al 8014 H21 non-anodized Cr 5 (Cr 0,65 In the 0,35 )N (Cermet) 31 (Cr 0,55 In the 0,45 )N (Cermet) 21 Cr2O3 20 2 1d anthracite 32,0 -0,1 0,6 Al 8014 H21 non-anodized Cr 5 (Cr 0,72 In the 0,28 )N (Cermet) 33 (Cr 0,39 In the 0,41 )N (Cermet) 31 ZrO2 22 2 1e black 1,5 0,5 -1,0 Al 8014 H21 non-anodized Cr 5 (Cr 0,57 In the 0,43 )N (Cermet) 33 (Cr 0,35 In the 0,65 )N (Cermet) 18 SiO2 55 2 2a-1 steel blue 54,3 -13,2 -10,2 Al 1080 H111 not anodized Cr 10 CrO 1,2 (Cermet, 20 Atom-%metallisches Cr in Cr2O3) 52 ZrO2 3 2a-2 blue 39,8 -12,5 -28,1 Al 1080 H111 not anodized Cr 10 CrO 1,2 (Cermet, 20 Atom%metallisches Cr in Cr2O3) 40 ZrO2 20 3 2a-3 purple 18,0 24,4 -37,5 Al 1080 H111 not anodized Cr 10 CrO 1,2 (Cermet, 20 Atom%metallisches Cr in Cr2O3) 30 ZrO2 20 3 2a-4 bronze 35,8 17,5 40,1 Al 1080 H111 not anodized Cr 10 CrO 1,2 (Cermet, 20 Atom%metallisches Cr in Cr2O3) 19 ZrO2 20 3 2b gold 63,8 3,9 30,2 Al 1080 H111 not anodized Ti 5 NiV, 7% V 60 ZrO2 20 3 2c-1 red 42,5 20,1 4,9 Al 1080 H111 not anodized Cr 10 (Cr 0,3 In the 0,7 )N (Cermet) 72 Cr2O3 30 4 2c-2 blue 37,3 1,1 -20,6 Al 1080 H111 not anodized Cr 10 (Cr 0,3 In the 0,7 )N (Cermet) 97 Cr2O3 4 2c-3 green 53,4 -11,1 6,1 Al 1080 H111 not anodized Cr 10 (Cr 0,3 In the 0,7 )N (Cermet) 143 Cr2O3 80 4 2d copper 78,9 14,1 25,2 Al 1080 H111 not anodized Cr 10 Cu 80 SiAlO2, 10 at% Al 80 5 3 anthracite 28,2 -1,5 -1,3 Stainless steel 1.4404 Mon 5 CrN 39 CrO 1,1 N 0,1 (Cermet, 28Atom-% Cr, 5Atom-%CrN) 38 Cr2O3 56 6 Production of plastically deformed objects

[0158] The suitability of the composites produced according to the invention for plastic deformation by deep drawing or bending was demonstrated by the above description with reference to Fig. The methods described in section 7 are determined. Examples of defined deformed composites according to the present invention are given in the following. Fig. 9, Fig. 10 to Fig.Figure 11 shows microscopic images of the surface of a layer system built according to Example 1a with a total thickness of 340 nm, which was bent around rods of different radii. To achieve a total thickness of 340 nm, the layer system was deposited in a coil coating system at a coil speed 2.5 times lower than in the production of Example 1a.

[0159] Fig. 9: PVD-coated aluminum. PVD layer thickness 340 nm; substrate thickness 0.5 mm; bending radius 6 mm; elongation 4%; x 1000.

[0160] Fig. 10: PVD-coated aluminum. PVD layer thickness 340 nm; substrate thickness 0.5 mm; bending radius 3 mm; elongation 7.5%; x 1000.

[0161] Fig. 11: PVD-coated aluminum. PVD coating thickness 340 nm; substrate thickness 0.5 mm; bending radius 2 mm: elongation 11%.

[0162] In the Fig. 12 and Fig.13 shows a composite according to example 1c on 0.8mm thick aluminium, which was bent around a rod with a radius of 3 or 2mm.

[0163] Fig. 12: PVD-coated aluminum according to example 1c. Thickness of the PVD coating system 77nm; substrate thickness 0.8mm; bending radius 3mm: elongation 12%.

[0164] Fig. 13: PVD-coated aluminum according to example 1c. Thickness of the PVD coating system 77nm; substrate thickness 0.8mm; bending radius 2mm: elongation 17%.

[0165] Fig. Figure 8, on the other hand, shows an example with colored anodized aluminum, in which cracks with a width of more than 2 µm are visible.

[0166] Decorative parts without any defects visible to the naked eye could be produced from the composites manufactured in Examples 1 to 3 by deep drawing. Light microscopy examinations at 1000x magnification showed no cracks with a width greater than 2 µm in the areas most deformed by deep drawing. The decorative parts exhibited a metallic appearance and feel.

Claims

[1] Compound of: a substrate (1) made of aluminium, an aluminium alloy, steel, chrome-plated steel or stainless steel and a color-imparting layer system on at least one surface of the substrate (1), wherein the color-imparting layer system comprises: - an adhesive layer (2) with a layer thickness of 2 to 30 nm made of metallic chromium, molybdenum, tungsten, platinum, aluminium, titanium, zirconium, nickel or an alloy of two or more of these elements, which is applied to at least one surface of the substrate (1) by means of a PVD process, - a color-imparting layer (3) of copper, titanium, stainless steel, a Cu-Zn alloy, a Cu-Sn alloy, a Ni-Cu-Sn alloy, a non-ferromagnetic nickel alloy, CrN x , where 0.5 ≤ x ≤ 1.0, provided that the color-giving layer (3) is only made of CrN x is formed when the layer (4) described below is present, CrO y , where 0 < y < 1.5, as cermet, (Al n Cr 1-n )N x , where 0 < n < 1 and 0.5 ≤ x ≤ 1.0, or (Al n Cr 1-n )N x C z , where 0 < n < 1; 0 < x < 1.5; 0 < z < 1.0 and 0.5 < (x + z) < 1.5, which is applied to the adhesive layer (2) by means of a PVD process, - optionally an additional color-imparting layer (4) made of CrN x O y , where 0 < x < 1.0, 0 < y < 1.5 and 0.5 < y + x < 1.5, , (Al n Cr 1-n )N x , where 0 < n < 1 and 0.5 ≤ x ≤ 1.0, (Al n Cr 1-n )N x C z , where 0 < n < 1; 0 < x < 1.5; 0 < z < 1.0 and 0.5 < (x + z) < 1.5, TiO r N t , where 0 < r < 2 and 0 < t ≤ 1, titanium aluminum nitride or ZrO r N t, where 0 < r < 2 and 0 < t ≤ 1, which is applied to layer (3) by means of a PVD process, with the proviso that if layer (3) and (4) are made of (Al n Cr 1-n )N x or (Al n Cr 1-n )N x C z are formed, the ratio of Cr to Al of layer (4) differs from the ratio of Cr to Al of layer (3), and - a dielectric protective and adhesive layer (5) of Cr2O3, ZrO2, ZrO2 in which up to 20% of the Zr is replaced by Si or Ta, SiO2, SiO2 in which up to 20% of the Si is replaced by Al, Al2O3, Si3N4 or Nb2O5, which is applied to layer (3) or layer (4) by means of a PVD process or by means of a PECVD process, wherein layers (2), (3) and (5) and the optional layer (4) form the color-imparting layer system, where the total thickness of the color-imparting layer system is 400 nm or less. [2] Composite according to claim 1, wherein the total thickness of all layers of the color-imparting layer system is 40 nm to 400 nm, preferably 50 nm to 300 nm. [3] Composite according to claim 1 or 2, wherein the layer (2) has a layer thickness of 5 to 30 nm, preferably 5 to 20 nm, the layer (3) has a layer thickness of 5 to 200 nm, more preferably 10 to 150 nm, further preferably 10 to 100 nm or 15 to 60 nm or 20 to 50 nm, and / or the layer (5) has a layer thickness of 5 to 200 nm, more preferably 10 to 100 nm, more preferably 20 to 80 nm. [4] Composite according to any of the preceding claims, wherein the layer (4) has a layer thickness of 5 to 200 nm, preferably of 10 to 150 nm, more preferably of 10 to 100 nm or 15 to 60 nm or 20 to 50 nm. [5] Composite according to any of the preceding claims, wherein the metallic substrate is a sheet, a plate, a web or a foil. [6] Compound according to one of the preceding claims, wherein the material for the adhesive layer (2) is selected from chromium, titanium, molybdenum, aluminium or nickel, and / or the material for the color-imparting layer (3) made of copper, titanium, nickel-vanadium alloys, CrO y as cermet and (Al n Cr 1-n )N x selected, and / or the material for the optional coloring layer (4) made of (Al n Cr 1-n )N x , (Al n Cr 1-n )N x C z , CrN x O y , TiO r N t , titanium aluminum nitride and ZrO r N t is selected, and / or the material for the dielectric protective and adhesive layer (5) is selected from Cr2O3, ZrO2, SiO2, SiAlO2 and Nb2O5. [7] Composite according to one of the preceding claims, wherein the material for the layer (3) is made of CrO y , where 1 < y < 1.4, and (Al n Cr1-n )N x , where 0 < n < 1, preferably 0.20 ≤ n < 0.70, further preferably 0.25 ≤ n ≤ 0.70, and 0.5 ≤ x ≤ 1.0, preferably 0.95 ≤ x ≤ 1.0, is selected. [8] Composite according to one of the preceding claims, wherein the material for layer (4) is made of (Al n Cr 1-n )N x , where 0 < n < 1, preferably 0.20 ≤ n < 0.70, further preferably 0.40 ≤ n ≤ 0.68, (Al n Cr 1-n )N x C z , where 0 < n < 1, preferably 0 < n < 0.95, more preferably 0.20 ≤ n < 0.70; 0 < x < 1.5, 0 < z < 1.0; and 0.5 < (x + z) < 1.5, or CrN x O y with 0 < x < 1.0, 0 < y < 1.5 and 0.5 < y + x < 1.

5. [9] Composite according to one of the preceding claims, wherein a layer (4) of CrN x O y , where 0 < x < 1.0, 0 < y < 1.5 and 0.5 < y + x < 1.5 and a layer (3) of CrN x where 0.5 ≤ x ≤ 1.0, preferably 0.9 ≤ x ≤ 1.0, is present. [10] Compound according to any of the preceding claims, wherein layer (3) and / or layer (4) is a cermet. [11] Method for producing a plastically deformed object, comprising the steps: a. Producing a composite according to one of the preceding claims from a substrate (1) of aluminium, an aluminium alloy, steel, chrome-plated steel or stainless steel and a color-imparting layer system on at least one surface of the substrate (1), comprising: - Application of the adhesive layer (2) to at least one surface of the substrate (1) using a PVD process, - Application of the color-imparting layer (3) to the adhesive layer (2) using a PVD process, - optionally applying the further color-imparting layer (4) to layer (3) using a PVD process, and - Applying the dielectric protective and adhesive layer (5) to layer (3) or layer (4) using a PVD or PECVD process, wherein layers (2), (3) and (5) and the optional layer (4) form the coloring layer system, and wherein the total thickness of the coloring layer system is 400 nm or less to maintain the bond between the substrate (1) and the coloring layer system, and b. subsequently plastic deformation of the composite to obtain the plastically deformed object. [12] Method according to claim 11, wherein the plastic deformation of the composite is carried out by deep drawing or bending. [13] Method according to claim 11 or 12, wherein the substrate used has an elongation at break of greater than 10%, preferably greater than 20%. [14] Method according to any one of claims 11 to 13, wherein the substrate is a sheet of metal with a width of 1600 mm or less, preferably 1200 mm to 1300 mm, and a thickness of 0.1 mm to 1.5 mm, preferably 0.6 mm to 1.0 mm in the case of aluminium or an aluminium alloy and 0.2 mm to 0.6 mm in the case of steel, chrome-plated steel or stainless steel. [15] Method according to any one of claims 11 to 14, wherein the substrate is provided with a surface structuring by rolling, brushing, embossing, etching, polishing or a similar suitable method before the layers of the coloring layer system are applied. [16] Method according to any one of claims 11 to 15, wherein the substrate is degreased and passivated before applying the layers of the coloring layer system and / or the surface of the substrate is cleaned by a plasma process or several successively applied plasma processes before applying the layers of the coloring layer system. [17] Method according to one of claims 11 to 16, wherein the substrate is first in the form of a strip sheet in roll form and is then unrolled and is first cleaned in an air-to-air PVD strip coating system using one or more plasma processes and is subsequently coated with the layers of the color-giving coating system in individual deposition chambers in vacuum sequence. [18] Method according to any one of claims 11 to 17, wherein, after the color-giving layer system has been applied, a step of forming openings in the composite is carried out, preferably by punching, drilling, milling or laser cutting, and wherein the forming of openings is preferably carried out before the step of plastic deformation. [19] Method according to any one of claims 11 to 18, wherein a transparent or translucent protective layer (6) of lacquer or a transparent or translucent sol-gel layer (7) is applied to the plastically deformed object. [20] Method according to any one of claims 11 to 19, wherein the elongation of the composite during plastic deformation is 10% or less. [21] Plastically deformed object obtained by a method according to any one of claims 11 to 20. [22] Plastically deformed object according to claim 21, wherein it is a decorative element of a motor vehicle, a furniture element, an element for the interior design of houses, in particular elevators, or a facade element. [23] Plastically deformed object according to claim 21 or 22, wherein the produced plastically deformed object has no cracks in the color-giving layer system with a gap width greater than 2 µm. [24] Use of a composite according to any one of claims 1 to 10 for plastic deformation, in particular deep drawing or bending.

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