CH718071A2 - Process for depositing a coating on an article, such as a watch component and article coated by such a process. - Google Patents

Abstract

One aspect of the invention relates to an article (1) comprising a substrate (10) and a coating having a color with an interference effect for the decoration and/or protection of said article (1), said coating comprising: a first layer ( 11) opaque at least partially covering at least one surface of the substrate (10); a stack (20) of at least two semi-transparent layers (12, 13) deposited by an ALD process covering said first layer (11); the stack (20) having a thickness (e 2 ) depending on said color with an interference phenomenon of said coating.

Description

Technical field of the invention

The field of the invention relates to surface treatments of articles such as decorative articles or watch components, and in particular decorative and/or protective coatings for articles.

The invention relates more particularly to a process for depositing a decorative and/or protective coating making it possible to obtain a colored coating having an interference effect.

The process for depositing a coating according to the invention is particularly suitable for protecting and/or decorating decorative articles or components used in timepieces, such as for example plates, bridges , the cogs, the screws, the oscillating weights, the dials, the indexes, the appliques, the windows, the hands or any other component of the movement or the external trim of a timepiece.

[0004] The invention also relates to an article, such as a watch component coated by such a method.

Technology background

[0005] To obtain protective and/or decorative layers on different substrates, it is known practice to use physical vapor deposition (PVD) techniques.

[0006] These PVD methods are used, for example, to give a distinctive aesthetic appearance to visible elements used in the production of timepieces.

[0007] For example, it is known to apply coatings by a PVD method on metal parts giving them a shiny or matte appearance depending on the state of the initial surface, metallic grey, black or even colored depending on the process used. However, the range of colors that can be obtained by these techniques remains limited.

Furthermore, it is also known to deposit by PVD processes thin and transparent layers with a thickness comparable to or less than the wavelengths of visible light, which give the surfaces on which they are deposited a color attributable to an interference phenomenon, we then speak of interference color.

[0009] Such a method makes it possible to obtain different interference colors ranging from dark yellow to green, passing through shades of violet and blue. However, as seen previously, the color palette remains limited and when the parts to be coated are not flat, but of complex geometry, the color obtained is not uniform, which is not aesthetically satisfactory because the rendering is not very qualitative.

Also known is ALD (Atomic Layer Deposition) technology, which is a form of chemical vapor deposition (CVD). This ALD technology is used in watchmaking for the decoration and protection against corrosion of timepieces.

[0011] The document "Atomic Layer Deposition (ALD): a promising technology for the watch industry", SSC bulletin n°81, May 2016, describes in particular the possibility of using ALD technology, replacing PVD technology, for protection against corrosion and for depositing interference color coatings formed by a single thin transparent layer deposited directly on a reflective substrate.

[0012] In comparison with PVD technology, ALD technology makes it possible to obtain perfectly uniform layers ensuring homogeneity of thickness over the entire periphery of the part, thus imparting a uniform color to the surface of parts with complex geometry. ALD technology also allows coloring in the form of interference colors and the properties of the coatings obtained by ALD are particularly suitable for the protection of parts with complex geometries.

[0013] However, the ALD technology as described does not make it possible to further extend the palette of interference colors that it is possible to obtain.

[0014] Document CH 709 669 proposes producing a coating for the protection and/or decoration of a timepiece component comprising a first metallic layer deposited by a PVD method and a second semi-transparent layer deposited by a ALD method above the first layer, the second semi-transparent layer having a large thickness to obtain interference colors in the range of brown, magenta, blue, yellow, orange, purple, green, pink, depending on the increasing thickness of the semi-transparent ALD layer.

[0015] Document CH 709 669 proposes a solution making it possible to slightly broaden the palette of interference colors compared to the documents of the state of the art by proposing, for the same interference tone, the possibility of obtaining a darker shade or lighter, and therefore to vary the lightness (i.e. the L* parameter of the L*a*b color space), depending on whether a gray or shiny metallic PVD layer is used under the ALD layer.

[0016] However, the current coating processes do not make it possible to obtain a wide range of interference colors, which limits the possibilities of decorating watch components with interference phenomena.

Summary of the invention

[0017] In this context, the invention aims to provide a process for depositing a decorative and/or protective coating on a substrate free from the limitations of the known coating processes described above.

According to the invention, one of the aims of the invention is to propose a process for depositing a decorative and/or protective coating making it possible to obtain a wide range of interference colors in the same tone with variations in hue. close, and in particular a wide range of interferential colors in the tonality of blues.

To this end, the subject of the invention is a process for depositing a decorative and/or protective coating on a substrate for the formation of an article, such as a watch component, making it possible to color said substrate, said deposition process being characterized in that it comprises: a first step of depositing a first opaque layer on the substrate; a second step of deposition by an ALD (atomic layer deposition) method of a stack of at least two semi-transparent layers covering said first layer; the thickness of the stack being chosen so as to obtain a color with an interference phenomenon.

[0020] The formation of an interference color, or of a color exhibiting an interference phenomenon, is due to the shift between the light reflected by the first opaque layer at least partially covering a surface of the substrate; and that reflected by the stack of semi-transparent layers deposited by an ALD method, covering the opaque layer.

[0021] Thus, unlike the prior art documents cited above in which the color of the final coating is dependent on the material deposited by a PVD method on the watch component, the PVD layer can sometimes be coated with a transparent layer deposited by an ALD method for the sole purpose of protecting the PVD layer, the method according to the invention goes against the prejudices of the state of the art since the final color of the coating is determined by the combination of the opaque layer ( preferentially deposited by a PVD method) and the stacking of ALD layers which are not transparent but on the contrary semi-transparent in order to modify the L*a*b* parameters of the opaque layer.

[0022] Preferably, the first step is a step of depositing a first metal or ceramic layer on said substrate.

Preferably, said first layer is a layer of TiN, TiCN, TiCNO, TiC, ZrN, ZrCN, ZrCNO, ZrC, HfN, HfCN, HfCNO, HfC, YN, YC, YCN, YCNO, TaN, TaC, TaCN, TaCNO, AIN, AICN, AICNO, CrN, CrC, CrNO, CrCNO, VN, VC, VCN, VCNO, TiZrN, TiZrCN, TiZrC, TiZrCNO, NbN, NbC, NbCN, NbCNO, WN, WC, WCN, WCNO, MoN, MoC, MoCN, or MoCNO.

Preferably, the chemical nature of said first layer is chosen according to the L* parameter according to the CIELAB standard of said color with an interference phenomenon of said coating.

Preferably, the first step is carried out by a PVD process (Physical Vapor Deposition).

Preferably, the first layer has a thickness (e1) greater than 450 nm, preferably between 500 nm and 1 μm.

Preferably, said at least two semi-transparent layers of the stack are of different chemical natures and/or have a different refractive index.

Preferably, the thicknesses of each of said at least two semi-transparent layers of the stack are chosen according to the parameters a* and b*, according to the CIELAB standard, of said color with an interference phenomenon of the coating.

Preferably, said at least two semi-transparent layers of the stack deposited during the second step are layers of a material chosen from among dielectric, semi-conductor, metallic or even ceramic materials.

Preferably, said at least two semi-transparent layers of the stack deposited during the second step are layers of a material chosen from: Al2O3, TiO2, SiO2, Ta2O5, HfO2, ZrO2, ZnO, SnO, Al , Ru, Ir, Pt, TiN, TaN, Si3N4, WN, NbN.

Preferably, a first semi-transparent layer of said at least two semi-transparent layers of the stack has a refractive index of less than 2, preferably less than 1.6, and a second semi-transparent layer of said at least two semi-transparent layers of the stack have a refractive index greater than 2, preferably greater than 2.5.

The invention also relates to an article comprising a substrate and a coating having a color with an interference effect for the decoration and/or the protection of said article, said coating comprising: a first opaque layer at least partially covering at least one surface of the substrate; a stack of at least two semi-transparent layers deposited by an ALD (Atomic Layer Deposition) process covering said first layer; the stack have a thickness depending on said color with an interference phenomenon of said coating.

[0033] Preferably, the first layer is a metallic layer or a ceramic layer.

Preferably, the first layer is a layer of TiN, TiCN, TiCNO, TiC, ZrN, ZrCN, ZrCNO, ZrC, HfN, HfCN, HfCNO, HfC, YN, YC, YCN, YCNO, TaN, TaC, TaCN, TaCNO, AIN, AICN, AICNO, CrN, CrC, CrNO, CrCNO, VN, VC, VCN, VCNO, TiZrN, TiZrCN, TiZrC, TiZrCNO, NbN, NbC, NbCN, NbCNO, WN, WC, WCN, WCNO, MoN, MoC, MoCN, or MoCNO.

Preferably, the chemical nature of said first layer (11) depends on the L* parameter according to the CIELAB standard of said color with an interference phenomenon of said coating.

Preferably, the first layer is deposited by a PVD process (Physical Vapor Deposition).

Preferably, the first layer has a thickness e1 greater than 450 nm, preferably between 500 nm and 1 μm.

Preferably, said at least two semi-transparent layers of the stack are of different chemical natures and/or have a different refractive index.

Preferably, the thicknesses of each of said at least two semi-transparent layers of the stack are a function of parameters a* and b*, according to the CIELAB standard, of said color with an interference phenomenon of the coating.

[0040]Preferably, said at least two semi-transparent layers of the stack are layers of a material chosen from among dielectric, semiconductor, metallic or even ceramic materials.

Preferably, said at least two semi-transparent layers of the stack are layers of a material chosen from: Al2O3, TiO2, SiO2, Ta2O5, HfO2, ZrO2, ZnO, SnO, Al, Ru, Ir, Pt , TiN, TaN, Si3N4, WN, NbN.

Preferably, a first semi-transparent layer of said at least two semi-transparent layers of the stack has a refractive index of less than 2, preferably less than 1.6, and a second semi-transparent layer of said at least two semi-transparent layers of the stack have a refractive index greater than 2, preferably greater than 2.5.

[0043] Preferably, the article is a watch component.

The invention also relates to a timepiece comprising a timepiece component.

Brief description of figures

The aims, advantages and characteristics of the present invention will appear on reading the detailed description below referring to the following figures: FIG. 1 schematically illustrates an example of a multilayer structure of a decorative and/or protective coating according to the invention deposited on a substrate forming an article, such as a watch component; FIG. 2 illustrates the main successive steps of an exemplary embodiment of the process for depositing a decorative and/or protective coating on a substrate for the production of an article, such as a timepiece component, according to the invention; FIG. 3 illustrates an embodiment of an article according to the invention.

Detailed description of the invention

In the present description, the colorimetric properties of the coating obtained according to the process for depositing a coating according to the invention are expressed using the CIE L*a*b* colorimetric space and measured according to the standard CIE 1976 on samples polished with a KONICA MINOLTA CM-3610-A spectrophotometer, with the following parameters: CIE D65 illumination source (6500°K daylight), 10° tilt, SCI measurements (specular reflection included), measuring area 4 mm in diameter.

[0047] A CIELAB colorimetric space (in accordance with CIE n°15, ISO 7724/1, DIN 5033 Teil 7, ASTM E-1164) has a luminance component L*, representative of the way in which the material reflects light, comparable to lightness, with an a* component which is the green/red component and a b* component which is the blue/yellow component.

[0048] Figure 1 schematically illustrates a sectional view of an article 1, such as a watch component, comprising a substrate 10 as well as a multilayer structure of a decorative and/or protective coating deposited on a substrate by means of of the process for depositing a coating according to the invention.

[0049] Article 1 is for example a watch component, for example a plate, a bridge, a wheel, a screw, an oscillating weight, a dial, an index, an applique, a window, a needle or any other component or component of a timepiece movement or of a covering component of a timepiece to which it is desired to give a color, and in particular an interference color.

[0050] Figure 3 illustrates a timepiece 200 comprising an article 1 according to the invention. In this embodiment, the article 1 according to the invention is a needle.

[0051] The substrate 10 may be of variable nature, for example made of metallic material, plastic material or even ceramic material, or even composite material, and may have a variable color. Thanks to the method according to the invention, it is possible to obtain the same final interference color L*a*b* with substrates of different nature and/or color.

The substrate 10 has at least one surface covered at least partially by a first layer 11 deposited by a process of physical vapor deposition or PVD (for Physical Vapor Deposition), which is itself covered by a stack 20 d at least two semi-transparent layers 12, 13 deposited by an ALD process so as to form a multilayer structure.

The first PVD layer 11 and the two semi-transparent layers 12, 13 ALD can also completely cover the substrate 10, i.e. all the faces of the substrate 10, or only the visible faces of the substrate 10.

The first layer 11 has an intrinsic color and has a sufficient thickness for it to be opaque and for the optical disturbance of the substrate 10 to no longer be active.

Preferably, the first layer 11 has a thickness equal to or greater than 450 nm, and more preferably a thickness e1 comprised between 500 nm and 1 μm. Thus, it is ensured that the color of the substrate 10 will not optically disturb the L*a*b* color of the final coating.

The first layer 11 can be a metallic layer or a ceramic layer.

Preferably, the first layer 11 is a layer based on ceramic material. The use of a first layer 11 based on ceramic material advantageously makes it possible to be able to extend the range of possible colors at the level of the first layer 11, in comparison with a first layer based on metallic material, the tones of which are limited to the yellow, gray, white. Thus, by widening the palette of colors of the first layer 11, it is possible to increase the palette of interference colors of the final coating by influencing the clarity/brightness of the interference color (i.e. by influencing the parameter L*).

By way of example, the first layer 11 is a layer based on a ceramic material selected from the group consisting of TiN, TiCN, TiCNO, TiC, ZrN, ZrCN, ZrCNO, ZrC, HfN, HfCN, HfCNO , HfC, YN, YC, YCN, YCNO, TaN, TaC, TaCN, TaCNO, AIN, AICN, AICNO, CrN, CrC, CrNO, CrCNO, VN, VC, VCN, VCNO, TiZrN, TiZrCN, TiZrC, TiZrCNO, NbN , NbC, NbCN, NbCNO, WN, WC, WCN, WCNO, MoN, MoC, MoCN, or MoCNO.

Thus, thanks to the use of such ceramic materials, it is possible to obtain a first layer 11 deposited by a PVD process, with a red, orange, yellow, green, blue, violet, pink, brown, black, white or gray.

[0060] Advantageously, the material of the first layer 11 will be chosen so as to have a first layer 11 with coordinates a* and b* close to zero, so that the first layer 11 has a neutral tone with no green or red tendency. , blue or even yellow.

The first layer 11 is covered by a stack 20 of a plurality of semi-transparent layers 12, 13 deposited by an atomic layer deposition process or ALD (for Atomic Layer Deposition). In the exemplary embodiment represented in FIG. 1, the stack 20 comprises two semi-transparent layers 12 and 13 thus forming a second layer 12 and a third layer 13 of the multilayer structure of the coating according to the invention.

Of course, the stack 20 deposited by ALD can consist of more than two semi-transparent layers.

The different semi-transparent layers of the stack 20 are advantageously of different chemical natures. In this case, the second layer 12 and the third layer 13 are of different chemical natures.

When the stack 20 comprises at least three semi-transparent layers, at least two layers of the stack are of different chemical natures. Advantageously, the two layers of different chemical natures are deposited successively.

Preferably, the different semi-transparent layers of the stack have a different refractive index n. In this case, the second layer 12 and the third layer 13 deposited by an ALD process have a different refractive index n.

When the stack 20 comprises at least three semi-transparent layers, at least two layers of the stack have a different refractive index n. Advantageously, the two layers having a different refractive index n are deposited successively.

Preferably, one of the layers of the stack 20 deposited by ALD, for example the second layer 12, is a layer with a low refractive index (i.e. less than 2, and preferably less than 1.6) while the another layer of the ALD stack, for example the third layer 13, is a layer with a high refractive index (i.e. greater than 2, and preferably greater than 2.5). Of course, the reverse is also envisaged.

The semi-transparent layers 12 and 13 of the stack 20 can be layers based on dielectric, semi-conductor, metal, or even ceramic material.

Each of the semi-transparent layers 12, 13 of the stack 20 deposited by an ALD process can be, for example, an aluminum oxide Al2O3, a titanium oxide TiO2, a silicon oxide SiO2, a tantalum oxide Ta2O5 , a hafnium oxide HfO2, a zirconium oxide ZrO2, a zinc oxide ZnO, or else a tin oxide SnO.

Each of the semi-transparent layers 12, 13 can also be a very thin layer of metal (Al, Ru, Ir, Pt), nitride-based ceramic material (Si3N4, WN, NbN, TiN, TaN) or still carbide, as mentioned above with reference to the first sub-layer 11.

The thickness e2 of the stack 20 is chosen according to the interference color that it is desired to obtain and so that the thickness e2 is comparable to or less than the wavelength of the desired color.

[0072] Conventionally, to obtain an interference color, the thickness e2 of the ALD stack is preferably between 50 nm and 200 nm.

FIG. 2 illustrates the main steps of the process 100 for depositing a coating on a substrate 10 according to the invention. Thus, the deposition method 100 according to the invention comprises a first step 110 of depositing a first layer 11 produced by a physical vapor phase deposition (PVD for Physical Vapor Deposition) method.

For example, the first step 110 of depositing a first layer 11 is carried out by a sputtering process. The spray gas is inert, typically argon. The PVD deposition parameters are determined by those skilled in the art so as to obtain a satisfactory opacity of the first layer 11 and so that the optical disturbance of the substrate 10 is no longer active.

The method for depositing a coating 100 according to the invention further comprises a second deposition step 120 carried out by an atomic layer deposition or ALD (for Atomic Layer Deposition) method, the second step occurring after the first step 110 so that the different atomic layers are deposited by successive stacking on the first PVD layer 11 .

The ALD process is a process for deposition of atomic thin layers which is part of chemical vapor deposition, or CVD (for Chemical Vapor Deposition). It makes it possible, from a gaseous precursor, to deposit monatomic layers which are individually oxidized to obtain a continuous layer of oxide.

By way of example, it is known to use the precursor trimethylaluminum (TMA, Al(CH3)3) to obtain Al2O3 layers, and the precursor tetrakis dimethylamide of titanium (TDMAT, C8H24N4Ti) to obtain layers of TiO2.

The second step 120 of ALD deposition comprises a first sub-step 121 of deposition by an ALD process of the second layer 12 described previously and a second sub-step 122 of deposition by an ALD process of the third layer 13 described previously , the second layer 12 and the third layer 13 being of different chemical natures and having different refractive indices n.

Of course, this second step 120 of the deposition process 100 according to the invention may comprise as many layer deposition sub-steps by an ALD process as the stack 20 comprises semi-transparent layers.

In addition, the use of a stack 20 of semi-transparent layers 12, 13 of different compositions, successively deposited by an ALD process, makes it possible to be able to combine several refractive indices inside the ALD stack. . Such a combination advantageously makes it possible to vary the parameters a* and b* of the colorimetric space L*a*b*, and therefore the hue of the final interference color without however modifying its tonality. Thus, the method according to the invention makes it possible to obtain, for example, different shades of blue with an interference phenomenon by varying the thicknesses of the ALD layers as well as the chemical nature of the ALD layers.

Thus, thanks to the process 100 for depositing a coating according to the invention, it is possible to interact with the L*a*b* colorimetric space of the color while keeping the desired interference phenomenon, by varying the following parameters: refractive indices n of the semi-transparent layers deposited by ALD, typically of the second layer 12 and of the third layer 13 in the embodiment illustrated in FIG. 1; extinction coefficient k of semi-transparent ALD layers; thicknesses of the semi-transparent layers inside the stack 20 deposited by ALD; refractive index n, extinction coefficient k and coordinates L*a*b* of the first layer 11 applied by PVD serving as a support for the semi-transparent layers ALD, by modifying the composition of the first PVD layer 11.

According to a first exemplary embodiment, to obtain a coating with an interference blue color having as color parameter L*=37.6±1.5, color parameter a*=-7.5±0.8, and color parameter b* = - 22.3 ± 0.8, the method according to the invention consists in depositing a first layer of CrC 500 nm thick by a PVD method, in depositing a second layer of TiO2de 34, 8 nm thick by an ALD method on the first PVD layer, followed by a third Al2O3 layer 39.3 nm thick by an ALD method.

According to a second exemplary embodiment, to obtain a coating with an interference blue color having as color parameter L*=31.6±1.5, color parameter a*=-7.1±0.8, and color parameter b* = - 22.8 ± 0.8, the method according to the invention consists in depositing a first layer of CrC 500 nm thick by a PVD method, in depositing a second layer of TiO2de 41, 0 nm thick by an ALD method on the first PVD layer, followed by a third Al2O3 layer 25.0 nm thick by an ALD method.

According to a third exemplary embodiment, to obtain a coating with an interference blue color having as color parameter L*=32.6±1.5, color parameter a*=-5.7±0.8, and color parameter b* = - 27 ± 0.8, the method according to the invention consists in depositing a first layer of CrC 500 nm thick by a PVD method, in depositing a second layer of Al2O3 of 10 nm d thickness by an ALD method, followed by a third layer of TiO2 55 nm thick by an ALD method.

Of course, other combinations of materials (other than Al2O3/TiO2) can be envisaged to obtain different shades of interference colors.

It is thus possible to use and combine different oxides among Al2O3, TiO2, SiO2, Ta2O5, HfO2, ZrO2, ZnO, SnO.

The stack 20 can also have three, four or even five semi-transparent layers with different refractive indices so as to further increase the range of possible tints for the same interference color tone. Care should be taken, however, that the total thickness of the stack 20 does not have a thickness greater than 200 nm so as to obtain a color with an interference effect.

The different layers of the coating according to the invention, and more particularly the first PVD layer 11 and the stack 20 of ALD layers, typically the second layer 12 and the third layer 13, can be deposited in two separate reactors, or in a single and unique reactor without departing from the scope of the invention.

Prior to the deposition steps 110, 120 described above, the method 100 according to the invention may also optionally comprise a step 105 for preparing the substrate 10.

This preparation step 105 may include a step of cleaning the substrate 10. In a manner known to those skilled in the art, this cleaning step can be carried out for example by chemical degreasing, followed by rinsing with water. city water and demineralised water. The substrate 10 is then dried and is ready for the implementation of the deposition steps 110, 120 mentioned previously.

This preparation step 105 can also include an ion activation step. The ion activation parameters are determined by those skilled in the art. Ionic activation guarantees perfect adhesion of the first PVD layer 11 deposited directly on the bare surfaces of the substrate 10.

The process for depositing a decorative and/or protective coating according to the invention has many advantages: it makes it possible to control the interference colorimetry obtained independently of the nature of the substrate and of the initial color of the watch component; the deposition of the coating is carried out at low temperature which makes it possible not to influence the crystalline structure of the watch component; consequently, the process for depositing a coating according to the invention is applicable to a wide variety of watch components; it makes it possible to adjust with great simplicity and good reproducibility the different thicknesses of the layers deposited to the desired value to obtain the desired interference L*a*b* color; the thickness of each ALD layer, and therefore the final interference color of the timepiece component thus coated, is regular and repeatable.

Claims (28)

1. Process for depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), such as a watch component, making it possible to color said substrate (10), said deposition method (100) being characterized in that it comprises: – a first step (110) of depositing a first opaque layer (11) on the substrate (10); - a second step (120) of deposition by an ALD (atomic layer deposition) method of a stack (20) of at least two semi-transparent layers (12, 13) covering said first layer (11); the thickness (e2) of the stack (20) being chosen so as to obtain a color with an interference phenomenon. 2. Method for depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to the preceding claim, characterized in that the first step (110) is a step of depositing a first metal or ceramic layer (11) on said substrate (10). 3. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to the preceding claim, characterized in that the said first layer (11) is a layer of TiN, TiCN, TiCNO, TiC, ZrN, ZrCN, ZrCNO, ZrC, HfN, HfCN, HfCNO, HfC, YN, YC, YCN, YCNO, TaN, TaC, TaCN, TaCNO, AIN, AICN, AICNO, CrN, CrC, CrNO, CrCNO, VN, VC, VCN, VCNO, TiZrN, TiZrCN, TiZrC, TiZrCNO, NbN, NbC, NbCN, NbCNO, WN, WC, WCN, WCNO, MoN, MoC, MoCN, or MoCNO. 4. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to the preceding claim, characterized in that the chemical nature of said first layer ( 11) is chosen according to the L* parameter according to the CIELAB standard of said color with an interference phenomenon of said coating. 5. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to one of the preceding claims, characterized in that the first step ( 110) is produced by a PVD process (physical vapor deposition). 6. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to one of the preceding claims, characterized in that the first layer ( 11) deposited during the first step (110) has a thickness (e1) greater than 450 nm, preferably between 500 nm and 1 μm. 7. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to one of the preceding claims, characterized in that said at least two semi-transparent layers (12, 13) of the stack (20) are of different chemical natures and/or have a different refractive index. 8. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to one of the preceding claims, characterized in that the thicknesses of each said at least two semi-transparent layers (12, 13) of the stack (20) are chosen according to the parameters a* and b*, according to the CIELAB standard, of said color with an interference phenomenon of the coating. 9. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to one of the preceding claims, characterized in that said at least two semi-transparent layers (12, 13) of the stack (20) deposited during the second step (120) are layers of a material chosen from among dielectric, semi-conductor, metallic or even ceramic materials. 10. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to one of the preceding claims, characterized in that said at least two semi-transparent layers (12, 13) of the stack (20) deposited during the second step (120) are layers of a material chosen from: Al2O3, TiO2, SiO2, Ta2O5, HfO2, ZrO2, ZnO, SnO , Al, Ru, Ir, Pt, TiN, TaN, Si3N4, WN, NbN. 11. Method of depositing (100) a decorative and/or protective coating on a substrate (10) for the formation of an article (1), according to one of the preceding claims, characterized in that a first layer semi-transparent (12) of said at least two semi-transparent layers (12, 13) of the stack (20) has a refractive index of less than 2, preferably less than 1.6, and in that a second layer semi-transparent (13) of said at least two semi-transparent layers (12, 13) of the stack (20) has a refractive index greater than 2, preferably greater than 2.5. 12. Article (1) comprising a substrate (10) and a coating having a color with an interference effect for the decoration and/or the protection of said article (1), said coating comprising: – a first opaque layer (11) at least partially covering at least one surface of the substrate (10); – a stack (20) of at least two semi-transparent layers (12, 13) deposited by an ALD (Atomic Layer Deposition) process covering said first layer (11); the stack (20) having a thickness (e2) depending on said color with an interference phenomenon of said coating. 13. Article (1) according to claim 12 characterized in that said first layer (11) is a metallic layer or a ceramic layer. 14. Article (1) according to claim 12 characterized in that said first layer (11) is a layer of TiN, TiCN, TiCNO, TiC, ZrN, ZrCN, ZrCNO, ZrC, HfN, HfCN, HfCNO, HfC, YN, YC, YCN, YCNO, TaN, TaC, TaCN, TaCNO, AIN, AICN, AICNO, CrN, CrC, CrNO, CrCNO, VN, VC, VCN, VCNO, TiZrN, TiZrCN, TiZrC, TiZrCNO, NbN, NbC, NbCN, NbCNO, WN, WC, WCN, WCNO, MoN, MoC, MoCN, or MoCNO. 15. Article (1) according to one of claims 12 to 14 characterized in that the chemical nature of said first layer (11) is a function of the L* parameter according to the CIELAB standard of said color with an interference phenomenon of said coating . 16. Article (1) according to one of claims 12 to 15 characterized in that the first layer (11) is deposited by a PVD process (physical vapor deposition). 17. Article (1) according to one of claims 12 to 16 characterized in that the first layer (11) has a thickness (e1) greater than 450 nm, preferably between 500 nm and 1 μm. 18. Article (1) according to one of claims 12 to 17 characterized in that said at least two semi-transparent layers (12, 13) of the stack (20) are of different chemical natures and/or have an index different refraction. 19. Article (1) according to one of claims 12 to 18 characterized in that the thicknesses of each of said at least two semi-transparent layers (12, 13) of the stack (20) are a function of the parameters a* and b*, according to the CIELAB standard, of said color with a coating interference phenomenon. 20. Article (1) according to one of claims 12 to 19 characterized in that said at least two semi-transparent layers (12, 13) of the stack (20) are layers of a material chosen from the materials dielectrics, semiconductors, metals, or even ceramics. 21. Article (1) according to one of claims 12 to 19 characterized in that said at least two semi-transparent layers (12, 13) of the stack (20) are layers of a material chosen from: Al2O3 , TiO2, SiO2, Ta2O5, HfO2, ZrO2, ZnO, SnO, Al, Ru, Ir, Pt, TiN, TaN, Si3N4, WN, NbN. 22. Article (1) according to one of claims 12 to 21 characterized in that a first semi-transparent layer (12) of said at least two semi-transparent layers (12, 13) of the stack (20) has a refractive index of less than 2, preferably less than 1.6, and in that a second semi-transparent layer (13) of said at least two semi-transparent layers (12, 13) of the stack (20) has a refractive index greater than 2, preferably greater than 2.5. 23. Article (1) according to one of claims 12 to 22 characterized in that said stack (20) of at least two semi-transparent layers (12, 13) deposited by an ALD (atomic layer deposition) process has a thickness (e2) of between 50 nm and 200 nm. 24. Article (1) according to one of claims 12 to 23 characterized in that said first opaque layer (11) of the coating is a layer of Crc having a thickness (e1) equal to 500 nm, and in that said stack (20) consists of a second semi-transparent layer (12) of TiO2 having a thickness of 34.8 nm and a third semi-transparent layer (13) of Al2O3 having a thickness of 39.3 nm. 25. Article (1) according to one of claims 12 to 23 characterized in that said first opaque layer (11) of the coating is a layer of Crc having a thickness (e1) equal to 500 nm, and in that said stack (20) consists of a second semi-transparent layer (12) of TiO2 having a thickness of 41.0 nm and a third semi-transparent layer (13) of Al2O3 having a thickness of 25.0 nm. 26. Article (1) according to one of claims 12 to 23 characterized in that said first opaque layer (11) of the coating is a layer of Crc having a thickness (e1) equal to 500 nm, and in that said stack (20) consists of a second semi-transparent layer (12) of Al2O3 having a thickness of 10 nm and a third semi-transparent layer (13) of TiO2 having a thickness of 55 nm. 27. Article (1) according to one of claims 12 to 26 characterized in that said article (1) is a watch component. 28. Timepiece (200) comprising a timepiece component according to the preceding claim.