Black Component

Abstract

The present invention relates to an internal part or movement of a timepiece or a component intended for jewelry, comprising a substrate (2) at least partially coated with a black coating (3) comprising aluminum oxide, and also to a process for manufacturing said component.

Description

[Technical field]

[0001] The present invention relates to a component, at least partially coated with black, intended for an internal part or movement of a timepiece or for an item of jewellery, and also to a process for manufacturing said component. [Background technology]

[0002] Black "color" can be obtained in a mass of material by the inherent color of the material or by adding pigments or colorants to the material. Black "color" can also be present only on the surface. This surface coloration can be obtained from various materials, generally by oxidation / sulfurization / carburization of a metallic substrate or by depositing oxides / sulfides / carbides on the substrate. Carbon is therefore well known as an element that blackens surfaces. The material deposited longitudinally in the form of nanotubes is comparable to a perfectly absorbing black body that can give a light absorption coefficient of up to 99.96% in the visible and near infrared ranges. This blackness is so perfect that it can hide the 3D shape of the object when viewed from the front.

[0003] The use of black coatings is known in the field of watchmaking. From document EP 3 327 517, a dial is known which has a first substrate coated with a black coating of nanotubes facing the watch glass and a second substrate fixed to the first substrate on its surface facing the glass. The first substrate is perforated to create openings which serve as windows for forming the indices. The second substrate, at least in the zone facing the openings, comprises a luminescent coating which creates a contrast between the black coating and the illuminated indices on the first substrate.

[0004] Contrast is therefore achieved by superposing two substrates with distinct coatings, which avoids the selective deposition of both coatings on the same surface and the unnecessary handling of the coatings on the particularly fragile nanotubes. Nevertheless, this has the disadvantage that it requires the production of two substrates, which increases the production costs.

[0005] From document CH 711 141 a process for producing a dial is known, in which the decoration, i.e. the indexes, are applied to a carbon black coating. The decoration is produced separately from the dial and can be easily attached, which greatly simplifies the manufacture of the dial.

[0006] At present, these ultra-black absorbent deposits are formed from vertically growing carbon nanotube forests using chemical vapor deposition. To maximize the intense black appearance of the coating on the substrate, the majority of the carbon nanotubes must be deposited in a controlled manner perpendicular to the substrate. This process, applied directly to the timepiece, is complex to implement. In an alternative process, a paint or varnish based on carbon nanotubes can be applied by spraying. This second process is simpler to implement, but produces a lower intensity of black. In both cases, the application and use of carbon nanotubes is complex to implement and may pose potential safety hazards during the manufacture of the coating, during the assembly of the timepiece, and during after-sales service operations. Furthermore, the forest structure of carbon nanotube-based coatings is very fragile and difficult to handle. These coatings have very low mechanical strength and are easily crushed even under the influence of light mechanical pressure. The coatings are so brittle that it is virtually impossible to touch them without damaging the surface, resulting in shiny blooms or holes that contrast with the original color of the carbon nanotubes. Furthermore, the forest structure of the coating does not allow overlapping decorations to be applied to the surface using normal direct printing techniques. Summary of the Invention

[0007] The object of the present invention is to overcome the drawbacks of carbon nanotube based coatings by providing an alternative type of superabsorbent, stronger and more compact black coating, allowing normal handling and decoration operations in the field of watchmaking or jewellery.

[0008] According to the invention, the black coating comprises a metal oxide, in particular aluminium oxide, deposited by a process of the PVD, CVD or PECVD type. This ultra-black decorative coating is a reflectance of less than 1.5% and a luminance value L of less than 12, preferably less than 7 in CIELAB, allowing high luminance and color contrasts for decoration; - a compact construction which allows the attachment of decorations to the surface of the covering; - micrometer thicknesses that allow the consolidation of parts with complex surface geometries and / or characteristic watch decorations; - It has the characteristic of having a mechanical strength which allows it to be handled for the assembly or decoration of the coated parts of the watch.

[0009] The present invention relates to a component at least partially coated with this black coating, and to a process for said component.

[0010] Further features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view of a timepiece including a dial that has been coated and decorated in accordance with the method of the present invention. [Figure 2A] FIG. 2A is a schematic diagram of a different embodiment of a process according to the invention with the successive steps performed. [Figure 2B] FIG. 2B is a schematic diagram of a different embodiment of a process according to the invention with the successive steps performed. [Diagram 3]FIG. 3 is a schematic diagram of a different embodiment of the process according to the invention with the successive steps carried out. [Figure 4A] FIG. 4A is a schematic diagram of a different embodiment of a process according to the invention with the successive steps performed. [Figure 4B] FIG. 4B is a schematic diagram of a different embodiment of a process according to the invention with the successive steps performed. [Diagram 5] FIG. 5 is a schematic diagram of a different embodiment of the process according to the invention with the successive steps carried out. [Figure 6] FIG. 6 is a schematic diagram of a different embodiment of the process according to the invention with the successive steps carried out. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention relates to an internal part or movement of a timepiece or a component intended for a piece of jewellery. This component can be chosen from a non-limiting list including dials, flanges, hands, indexes, appliques, oscillating masses, plates, bridges, etc. According to the invention, this component is at least partially covered with a black coating. As will be explained below, the invention also relates to an assembly of two said components at least partially covered with a black coating.

[0013] The invention will be described below within the scope of its application to a watch dial 1 formed from a substrate 2 at least partially coated with a black coating 3, as represented diagrammatically in Figure 1. The substrate can be made of a metallic material such as steel, titanium, aluminium, a titanium or aluminium alloy, brass or any other alloy containing copper. The substrate can also be made of a ceramic material, a cermet, sapphire, glass, silicon, a composite material or a polymer.

[0014] According to the present invention, the black coating, also called black coating, is mainly made of Al 2 O 3 Aluminum oxide such as Al x Oy and a non-ferrous metal oxide, for example an oxide of copper, zinc, nickel, chromium, silver or manganese. The coating is at least 90% Al x O y , preferably 100% Al x O y The aluminum oxide has an aluminum content of between 45% and 65% by mass, preferably between 45% and 50% by mass. The layer has a thickness of between 1 and 50 microns, preferably between 2 and 10 microns, more preferably between 4 and 7 microns. It can be deposited by PVD (physical vapor deposition), CVD (chemical vapor deposition) or PECVD (plasma enhanced chemical vapor deposition).

[0015] The superabsorbent black deposit according to the invention has reflectance values ​​in the visible range of less than 2%, more specifically less than 1.5%, for coating thicknesses between 4 and 7 microns, as contained in Table 1. The measurements are total hemispherical reflectance (THR) measurements obtained by optical absorption spectroscopy.

[0016] TIFF0007602616000001.tif41170 Table 1

[0017] In the CIELAB color system (according to standards CIE No. 15, ISO 7724 / 1, DIN 5033 Teil 7, ASTM E-1164), the brightness of a timer coated in this way is: - L less than 12, preferably less than 7 * The value of - a between -2 and +2, preferably between -1 and +1 * The value of - b between -3.5 and +5, preferably between -3.5 and +1 * Value of It is characterized by:

[0018] The black coating has a dense microstructure. This compact structure allows decoration to be applied without damaging the black coating. The decorations can be of any type. They can consist of gemstone 4 indexes, optionally photoluminescent, set or glued on a substrate 2 as shown in Figure 1, and elements made of metallic materials, resins, composite materials, wood, mother of pearl, etc. They can also consist of luminescent elements such as LEDs.

[0019] The decoration is created or attached on the black coating or on parts of the substrate that are free of the black coating. These parts may be free of the black coating to begin with, or the coating may be selectively removed by machining, laser techniques, or ion or electron bombardment for functional or aesthetic reasons. Pulsed type lasers, in particular picosecond, nanosecond, or femtosecond type lasers, are chosen for the selective ablation of the black coating.

[0020] The decorations can be designed on the substrate by printing methods such as pad printing, digital printing, or additive manufacturing. They can also be designed by electroforming or by thermoforming of amorphous metals, and in alternative embodiments, the decorations are produced directly on the metal substrate in the areas not covered by the black coating. The decorations can also be attached with an adhesive.

[0021] According to an alternative embodiment of the invention, the decoration can also be placed under a discontinuous coating of black coating. Thus, the component includes a decoration on the surface of the substrate, such as a metal coating, a resin, or a lacquer, including a photoluminescent lacquer. The black coating is then deposited on the decoration and selectively removed at selected locations to expose the decoration and create a contrasting decoration. Optionally, another decoration can be designed or attached to the black coating.

[0022] The invention also relates to an assembly comprising a first component and a second component, each intended for an internal part or movement of a timepiece, or for a piece of jewelry. According to the invention, the first component and the second component comprise at least one part coated with a black coating. Preferably, the first component has a relative movement with respect to the second component and is mounted facing the second component. This first component is decorated. For example, the first component is a hand coated and decorated with a black coating, and the second component is a dial coated with a black coating. For example, the hand is decorated with a gemstone set or glued to the tip of the hand.

[0023] Different alternative embodiments for manufacturing a component according to the invention are represented in FIGS. 2A to 6. FIG.

[0024] The process for manufacturing the components includes at least the following: a) providing a substrate 2 and machining said substrate, said substrate 2 being capable of having a relief structure after machining, as is represented diagrammatically in Figure 2B. - step b) providing at least a portion of the substrate 2 with a black coating 3 comprising mainly aluminium oxide.

[0025] Optionally, during step a), the substrate can be subjected to a micro-sandblasting or shotblasting pretreatment to increase the surface roughness (step not shown). The surface thus treated has a roughness Ra (arithmetic mean roughness) between 0.4 and 5 microns, preferably between 0.4 and 2 microns, measured with an Altisurf500 optical profilometer (ISO 4288:1996 / 4287:1997).

[0026] Alternatively, and again optionally, the substrate can be subjected to a plasma electrolytic anodizing or ceramization type electrolytic oxidation pretreatment in order to give the surface of the part a rough black appearance (step not shown). In this alternative embodiment, the substrate is preferably made of a titanium alloy, for example Ti-6Al-4V or Ti-CP3, an aluminum alloy, for example AA6061, AA2024, AA6082, an aluminum-titanium mixed alloy or an aluminum-lithium alloy. After this pretreatment, the substrate is subjected to a vacuum treatment in order to deposit an ultra-black coating on the surface.

[0027] Step b) consists of depositing a black coating on the substrate by PVD, CVD or PECVD. Alternatively, the black coating is deposited on a thin-film or strip-type support by PVD, CVD or PECVD and then glued onto the substrate (coating of adhesive or glue 5 in FIG. 5). The film or strip can be made of a polymer or metal material that, on the side opposite the coating, contains an adhesive intended to be fixed to the substrate.

[0028] The manufacturing process may further comprise a decorating step c) before and / or after step b), which consists of designing a decoration on the covered or uncovered part by means of a printing or electroforming method, which also consists of attaching a decoration to the covered or uncovered part, which may be fixed, for example, by gluing.

[0029] According to an alternative embodiment in Figures 3, 4A, 4B and 6, after the deposition of the black coating 3 in step b), there is at least one decoration step c), which can be preceded by a step d) of selectively removing the black coating 3 on the zones intended to be decorated in step c), as shown in Figures 4A, 4B and 6. This selective removal can be limited to the black coating 3 (Figures 4A and 6) or can be extended to the substrate 2 (Figure 4B).

[0030] Alternatively, the process may include a decorating step c) before the step b) of depositing the black coating 3, as shown in Figure 6. The substrate is machined and decorated with a first decoration 4. Then, in step b), the decorated substrate is coated with a black coating 3. Then, in step d), the black coating 3 is selectively removed to expose the first decoration 4 in certain parts. The manufacturing process may include a second step c) of decorating the parts that include the black coating 3. Preferably, the second decoration 4 only partially covers the black coating 3.

[0031] For all alternative embodiments, the process may further include the additional step (not shown) of depositing a hard protective coating over the black coating, with or without decoration. This coating may be TiO 2 , Al 2 O 3 , SiO 2 or a mixture of at least two of these oxides. This hard coating has a thickness of between 5 and 100 nm, preferably between 5 and 20 nm. [Explanation of symbols]

[0032] (1)Dial (2) Base material (3) Black coating (4) Ornament, also called the first ornament or the second ornament

Claims

1. An internal part or movement component for a timepiece or a component for a piece of jewelry, comprising a substrate (2) comprising at least one part coated with a black coating (3) comprising at least one aluminium oxide, said coated part having a black coating (3) having a black coating (3) of less than L 12 in the CIELAB colour system. ＊ Value of a between -2 and +2 ＊ Value of b between -3.5 and +5 ＊ wherein said black coating (3) comprises at least 90% aluminium oxide by weight, said aluminium oxide having an aluminium content between 45% and 65% by weight, said black coating (3) further having a thickness between 4 microns and 7 microns and a reflectance value of less than 1.5% in the visible range.

2. Component according to claim 1, characterized in that the black coating (3) comprises 100% by weight of aluminium oxide.

3. 2. The component of claim 1, wherein the aluminum oxide has an aluminum content of between 45% and 50% by weight.

4. Component according to claim 1, characterized in that it comprises a decoration (4) on the coated part of the black coating (3) or on another part of the substrate (2) free of the black coating (3).

5. 2. The component according to claim 1, further comprising a further decoration (4) disposed between said substrate (2) and said black coating (3), said black coating (3) being discontinuous to expose said further decoration (4).

6. Component according to claim 5, characterized in that the further decoration (4) is a metal coating, a resin or a lacquer, including a photoluminescent lacquer.

7. Component according to claim 4, characterized in that the decoration (4) is made from metal, polymer, composite material, from wood or from mother of pearl or contains LEDs.

8. Component according to claim 4, characterized in that the decoration (4) is an index or a jewel glued or set in the base material (2).

9. 9. The component of claim 8, wherein the index is photoluminescence.

10. 10. Component according to claim 9, characterized in that the black coating (3) is coated with a protective coating based on a metal oxide.

11. The protective coating is TiO ２ , Al ２ O ３ and / or SiO ２ The component of claim 10 comprising:

12. 2. The component according to claim 1, characterized in that it is selected from the group comprising dials, flanges, indexes, hands, appliques, oscillating masses, plates, and bridges.

13. Component according to claim 1, characterized in that the substrate (2) comprises a relief structure in its coated portion.

14. Assembly comprising a component according to claim 1 and an internal part of a timepiece or the movement, or another component of a piece of jewellery, characterized in that said other component is at least partially covered with said black coating (3).

15. 15. The assembly according to claim 14, characterized in that the other component is arranged facing the component and is mounted to have relative movement with respect to the component, the other component including an ornament (4).

16. Assembly according to claim 14, characterized in that said other component is a hand, said component being a dial, said hand including a decoration formed by a jewel (4).

17. A timepiece or an item of jewellery comprising a component according to claim 1 or an assembly according to claim 14.

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