Process for coloring metals and colored metals

Abstract

This invention relates to a method for coloring a metal part (20) to be treated, the method comprising the steps of: implanting single-charged or multi-charged ions into the surface layer of the part (20) to be treated by directing a single-charged or multi-charged ion beam generated by a single-charged or multi-charged ion source toward the part (20) to be treated, thereby changing the color of the part (20) under the influence of the ion implantation. This invention also relates to colored metals, particularly those obtainable by the above method.

Description

[0001] This application is a divisional application of application No. 202210367783.1, filed on April 2, 2022, entitled "Method for Coloring Metal and Colored Metal". Technical Field

[0002] This invention relates to a method for coloring metal parts, particularly metal parts embedded in ceramic materials. The invention also relates to colored metal parts obtained using this coloring method. Background Technology

[0003] Many metal coloring methods are known in the prior art. One such method is, for example, the coloring of aluminum. It is known that primary aluminum is naturally and uncontrolledly oxidized and colored, creating the appearance of stains or marks on the surface of the aluminum parts involved. To solve this problem, the aluminum parts can be artificially oxidized to make their appearance uniform and aesthetically pleasing. This controlled oxidation technique of aluminum is called anodizing. Anodizing is an electrochemical surface treatment method for aluminum that aims to create an oxide layer on the surface of an aluminum part. For this purpose, the aluminum part is immersed in a bath in which an electrolyte containing sulfuric acid is dispersed. By circulating a direct current in the bath, a porous oxide layer is formed on the surface of the aluminum part, the thickness of which is typically about tens of micrometers. This very hard oxide layer protects the surface of the aluminum part from corrosion and can subsequently be colored due to its porosity by trapping dye within the material.

[0004] At the British Museum in London, you can admire the Lycurgus Cup, named after the Spartan legislator from mythology. Made by Roman glassmakers in the 4th century BC, this cup appears green when illuminated from the front and red when illuminated from behind. This dichroism is attributed to the presence of small proportions of gold and silver nanoparticles within the glass, creating a plasmonic-type surface phenomenon. Surface plasmon resonance is observed when all the free electrons of a metal exposed to the same electromagnetic field, with wavelengths λ much larger than the size of the metal particles, collectively oscillate in phase. The metal nanoparticles exposed to light radiation thus exhibit light-scattering properties due to stimulated plasmon resonance. These properties depend on the shape of the particles, their size, their properties, and the medium in which they are dispersed.

[0005] Using the plasmonic effect to create color on metals has garnered significant interest due to its durability, as demonstrated by the Lycurgus cup, and the potential to avoid the use of inks, paints, or pigments. A Canadian research team has proposed a method for coloring metals using plasmonic technology. This technique involves creating controlled nanostructures on the surface of gold, silver, copper, or aluminum components using a laser beam. To achieve this, the metal components are treated with bursts of laser pulses generated by a laser emitting near-infrared light at a wavelength of 1.064 µm. The duration of the laser pulses is 10... -12 The laser beam is pulsed in a series of pulses, with each pulse occurring at equal intervals from the next. To ensure the laser beam follows the entire image to be created on the surface of the metal component, its displacement is maintained by a computer-controlled set of servo-controlled mirrors. These laser pulses thus create nanoparticles on the surface of the processed metal component and achieve a very complete color gamut. Summary of the Invention

[0006] The present invention aims to provide a new technique for coloring metals.

[0007] Therefore, the present invention relates to a method for coloring a metal component to be treated, the method comprising the steps of: injecting single-charged or multi-charged ion beams generated by a single-charged or multi-charged ion source into the surface layer of the component to be treated by directing the single-charged or multi-charged ion beams generated by a single-charged or multi-charged ion source into the component to be treated, thereby changing the color of the component to be treated under the influence of the ion implantation.

[0008] According to a specific embodiment of the present invention: - The single-charged or multi-charged ion source is an ECR ion source; - The component to be processed is fixed on a carrier component that is not sensitive to ion implantation; - The carrier component is a ceramic component; - The carrier component is an external component; - The external components are intended for use in watchmaking or jewelry making; - The external components are selected from the watch middle, watch case back, watch bezel, watch dial, watch bracelet or jewelry ink, bridge or plate of watch movement, watch hands and ring. - The metal used to make the component to be processed is selected from precious metals composed of gold, silver, platinum, palladium, ruthenium, iridium and alloys of these precious metals; - The component to be processed is made of copper, aluminum, zirconium, titanium, or an alloy of these metals; - The materials to be ionized are selected from carbon, nitrogen, oxygen, helium, and argon; - Single- or multi-charged ions are accelerated at voltages between 12.5 kV and 47.5 kV, with ion beam power between 4 mA and 15 mA and implanted ion doses between 5.10. 15 ions.cm -2 Up to 75.10 16 ions.cm -2 between; - Place the component to be processed in a vacuum chamber and inject a single-charged or multi-charged ion beam into it; - After ion implantation, the part to be treated is subjected to annealing heat treatment.

[0009] The present invention also relates to metal parts colored using the coloring method according to the present invention.

[0010] Benefiting from these features, the present invention provides a method for coloring metal parts, which are either in block form or fixed to a carrier part by any suitable means. It has indeed been recognized that by appropriately bombarding a metal part with an ion beam, it is possible to change the color of the metal part in a controlled and reproducible manner. This method is particularly significant when the metal part is fixed to a carrier part. In fact, as long as the carrier part is insensitive to ion bombardment, it is possible to change the color of the metal part without any specific precautions; in particular, lengthy and cumbersome masking operations are avoided. The method according to the invention is therefore particularly significant in the fields of watchmaking and jewelry making because it can color, for example, metal inserts such as hour markers fixed to ceramic parts such as bezels. Furthermore, the method according to the invention is simple and quick to implement and does not involve any polluting or toxic products. Attached Figure Description

[0011] Other features and advantages of the invention will become more apparent from the following detailed description of embodiments of the method according to the invention, an example of which is given by way of example only and not limitation with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of an ECR (electron cyclotron resonance) type ion source; Figure 2 This is a schematic diagram of an ion implantation apparatus for implementing the method according to the invention, and Figure 3A and 3B The illustration shows the color change of a component after ion implantation. Detailed Implementation

[0012] This invention, based on a creative overall concept, involves bombarding a solid metal component or a metal component attached to the surface of a carrier component with a single-charged or multi-charged ion beam to alter the color of the bombarded metal component. Thanks to these features, this invention provides a method for coloring metal components that does not use toxic or polluting products, and is therefore simple and quick to implement. Furthermore, when the metal component is attached to a carrier component, as long as the material of the carrier component is insensitive to ion bombardment, it is possible to change the color of the bombarded metal component without requiring lengthy and cumbersome masking operations.

[0013] To implement the method according to the invention, it is advantageous to use a single-charged or multi-charged ion source of the electron cyclotron resonance type. This device, also known as ECR, utilizes the cyclotron resonance of electrons to create plasma. A volume of low-pressure gas is ionized by injected microwaves, the frequency of which corresponds to the electron cyclotron resonance defined by a magnetic field applied to a region within the volume of gas to be ionized. The microwaves heat the free electrons present in the volume of gas to be ionized. These free electrons collide with atoms or gas molecules under thermal agitation, causing them to ionize. The resulting ions correspond to the type of gas used. The gas can be pure or complex. It can also be a vapor derived from a solid or liquid material. ECR ion sources can produce single-charged ions, i.e., ions with an ionization degree equal to +1, or multi-charged ions, i.e., ions with an ionization degree greater than +1. Ion beams can also be used for mixtures of single-charged and multi-charged ions.

[0014] Appendix to this patent application Figure 1 The diagram schematically illustrates an ECR (electron cyclotron resonance) type ion source. The ECR ion source, generally indicated by reference numeral 1, comprises an injection section 2 (introducing a gas volume 4 to be ionized and microwaves 6), a magnetic confinement section 8 (creating a plasma 10 therein), and an extraction section 12 capable of extracting and accelerating ions from the plasma 10 via an anode 14a and a cathode 14b (with a high voltage applied between them). An ion beam 16 generated at the output port of the ECR ion source 1 strikes the surface 18 of the component 20 to be treated and penetrates into the surface of the component 20.

[0015] The component to be processed 20 is a metal component. The metal used to make the component is preferably, but not limited to, a precious metal composed of gold, silver, platinum, palladium, ruthenium, iridium, and alloys of these precious metals. According to another specific embodiment of the invention, the component to be processed may be made of copper, aluminum, zirconium, titanium, or alloys of these metals.

[0016] Preferably, but not limitingly, the material to be ionized is selected from carbon, nitrogen, oxygen, helium, and argon, and single- or multi-charged ions are accelerated at a voltage between 12.5 kV and 47.5 kV. The ion beam power is between 4 mA and 15 mA, and the implanted ion dose is 5.10. 15 ions.cm -2 Up to 75.10 16 ions.cm -2 Between. Ion implantation is interrupted when the desired color is observed.

[0017] A schematic diagram of an ion implantation apparatus capable of implementing the method according to the invention is shown. Figure 2 The ion implantation apparatus, generally indicated by reference numeral 22, is contained within a vacuum chamber 24 in a sealed housing 26, in which the part to be treated, 20, is placed.

[0018] The component to be processed 20 can be block-shaped. It can also be an external component, particularly an external component used in watchmaking or jewelry, such as the bezel 28 of a watch. In a particular exemplary embodiment, the bezel 28 is made of ceramic material and receives metal inserts 30 in recesses formed on its surface. These metal inserts 30, whose color can be changed, for example, have a series of numbers and markings formed on the surface of the bezel 28, and their shape and / or their size can be variable (see...). Figure 3A ).

[0019] The ion source, here ECR 1 ion source, is sealed and fixed to the sealed housing 26 of the vacuum chamber 24, facing the opening 32 formed in the sealed housing 26. This ECR ion source 1, of the same type as described above, is oriented so that the generated single-charged or multi-charged ion beam 16 propagates within the sealed housing 26 and strikes the surface of the component 20 to be treated. The single-charged or multi-charged ions striking the component 20 penetrate more or less deeply into the surface of the component 20 and cause discoloration.

[0020] Several examples of implementing the method according to the present invention are given below, applied to a ceramic bezel 28 with a metal insert 30.

[0021] When the metal inserts 30 are made of an alloy of zirconium and aluminum, treating these metal inserts 30 with a nitrogen ion beam accelerated at a voltage of 35 kV and a power of 7 mA can achieve an ion implantation dose of 50.10. 16 ions.cm -2 These metal inserts are then given a 30% blue tint.

[0022] When the metal inserts 30 are made of titanium, treating them with a nitrogen ion beam accelerated at 37.5 kV and a power of 6 mA can achieve an ion implantation dose of 25.10.16 ions.cm -2 These metal inlays were then given a 30% gold color.

[0023] When the metal inserts 30 are made of titanium, treating them with a nitrogen ion beam accelerated at 20.0 kV and a power of 6 mA can achieve an ion implantation dose of 25.10. 16 ions.cm -2 These metal inserts are then given a 30% blue tint.

[0024] When the metal inserts 30 are made of titanium, treating them with an oxygen ion beam accelerated at 12.5 kV and a power of 4 mA can achieve an ion implantation dose of 25.10. 16 ions.cm -2 These metal inserts were then given a 30% purple hue.

[0025] Figure 3A and 3B The illustration schematically shows the color change of component 20 after treatment using the ion implantation method according to the invention. In the case of external components used in watchmaking, such as the ceramic bezel 28 (see...),... Figure 3A A color change was observed in the metal insert 30 after ion implantation (see...). Figure 3B ).

[0026] Needless to say, the present invention is not limited to the embodiments just described, and those skilled in the art will consider various simple modifications and variations without departing from the scope of the invention as defined by the appended claims. In particular, it should be noted that single-charged or multi-charged ions refer to ions whose ionization degree is equal to or greater than +1. It should also be noted that the ion beam may consist of ions all having the same degree of ionization, or may come from a mixture of ions with different degrees of ionization. Furthermore, it should be noted that, for example, in the case of processing metal inserts on ceramic bezels, a masking operation is unnecessary: ​​the entire surface of the bezel can be exposed to the ion beam, which does not change the mechanical properties or appearance of the ceramic material. Only the color of the metal insert changes. To make the color of the metal insert darker or even change it, it is possible to subject the treated part, such as a ceramic bezel with a metal insert, to an annealing heat treatment after the ion implantation treatment. In this case, the annealing treatment also does not affect the properties of the ceramic.

[0027] Tag list

[0028] 1. ECR ion source

[0029] 2. Injection segment

[0030] 4. Volume of gas to be ionized

[0031] 6. Microwave

[0032] 8. Magnetic confinement segment

[0033] 10. Plasma

[0034] 12. Extraction segment

[0035] 14a. Anode

[0036] 14b. Cathode

[0037] 16. Ion beam

[0038] 18. Surface

[0039] 20. Components to be processed

[0040] 22. Ion implantation device

[0041] 24. Vacuum chamber

[0042] 26. Sealed housing

[0043] 28. Bezel

[0044] 30. Metal inserts

[0045] 32. Opening

Claims

1. A method for coloring a metal part (20) to be treated, the method comprising the steps of: injecting single-charged or multi-charged ions into the surface layer of the part (20) to be treated by directing a single-charged or multi-charged ion beam generated by a single-charged or multi-charged ion source to the part (20) to be treated, thereby changing the color of the part (20) under the influence of the ion implantation.

2. The coloring method according to claim 1, characterized in that... The single-charged or multi-charged ion source is an ECR ion source (1).

3. The coloring method according to any one of claims 1 and 2, characterized in that... The component to be processed (20) is fixed on a carrier component that is not sensitive to ion implantation.

4. The coloring method according to claim 3, characterized in that... The carrier component is a ceramic component.

5. The coloring method according to claim 4, characterized in that... The carrier component is an external component.

6. The coloring method according to claim 5, characterized in that... The external components are intended for use in watchmaking or jewelry making.

7. The coloring method according to claim 6, characterized in that... The external components are selected from watch middle parts, watch case back, bezel, dial, watch strap or jewelry connector, watch movement bridge or plate, watch hands and ring.

8. The coloring method according to any one of claims 1 to 7, characterized in that... The metal used to make the component to be processed (20) is selected from precious metals consisting of gold, silver, platinum, palladium, ruthenium, iridium and alloys of these precious metals.

9. The coloring method according to any one of claims 1 to 7, characterized in that... The component to be processed (20) is made of copper, aluminum, zirconium, titanium or an alloy of these metals.

10. The coloring method according to any one of claims 1 to 9, characterized in that... The materials to be ionized are selected from carbon, nitrogen, oxygen, helium, and argon.

11. The coloring method according to claim 10, characterized in that... Single- or multi-charged ions were accelerated at voltages ranging from 12.5 kV to 47.5 kV, with ion beam power between 4 mA and 15 mA and implanted ion doses of 5.

10. 15 ions.cm -2 Up to 75.10 16 ions.cm -2 between.

12. The coloring method according to any one of claims 1 to 11, characterized in that... The component to be processed (20) is placed in a vacuum chamber (24) and a single-charged or multi-charged ion beam (16) is injected into it.

13. The coloring method according to claim 12, characterized in that... After ion implantation, the part to be treated (20) is subjected to annealing heat treatment.

14. A part to be treated, made of metal and colored by means of a coloring method according to any one of claims 1 to 13.

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