Method for manufacturing a gold alloy watch component and watch obtained thereby

Abstract

The present invention relates to a method for manufacturing a watch component, which comprises assembling gold alloys to create a powder mixture for producing an alloy having a particular color, said powders being combined and arranged to produce a visual effect on said watch component. The invention further relates to a watch component and to a watch comprising at least one said watch component.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a watch component based on several precious or noble metals and their alloys. In particular, at least one of these precious or noble metals is gold or its alloy. Preferably, the method described herein is applied to the production of several different types of gold-based watch components. Various precious metals, gold, or their alloys are individually atomized into separate powders and then mixed in predetermined proportions to produce a homogeneous mixed powder. The proportions of metals, gold, or corresponding alloys constituting the mixed powder are determined according to the color to be obtained in the finished component. The mixed powders are arranged relative to each other to form a color pattern, such as a gradient, and are subjected to a sintering operation, particularly SPS (spark plasma sintering), also known as flash sintering. Composite materials obtained from different mixed powders can be distinguished from one another in the watch component thus obtained, particularly by their color. This specification also covers watch components made of several separate gold alloys assembled into a composite material, as well as watches equipped with such components. [Background technology]

[0002] The principle of sintering powders of metallic materials is well known and is often used to produce metal alloys. Document EP 3766997, for example, describes the formation of precious metal alloys using such a process. However, such alloys require that all powders be mixed to form a single, preferably homogenized, mixture. Such a process does not allow the production of components with different local compositions.

[0003] Document EP 3822712 gives an example of a metal powder-based method for the design of timepiece components, which includes a surface melting step to remove defects.

[0004] Document WO2015061817 (Patent Document 3) describes a multiphase structure produced by intercalation or interpellation of different materials in a random, unique and individual arrangement that serves as an element of authentication for a piece of jewelry or luxury goods. The resulting multicolored macrostructure is difficult to reproduce and therefore acts as an anti-copy measure.

[0005] Document CN110328371A (Patent Document 4) describes a multi-step process in which different materials are successively placed in a mold and compressed with characteristic molding elements to produce the desired pattern.

[0006] Document CN111992731A (Patent Document 5) describes a method for embedding particles in gold to increase its hardness.

[0007] Sintering techniques are an alternative to brazing or welding, which has the advantage of limiting or avoiding the addition of material at the interface and the mixing of existing materials.Therefore, there is scope to develop processes specifically adapted to precious materials, especially gold alloys, that allow their wider use and assembly.

[0008] Furthermore, in the field of watchmaking, the aesthetic properties of the alloys used can be very important, in that they determine the appearance of the final piece. Although commercially available alloys may have aesthetic variations among themselves, their color is not adjustable, which limits the variety of colors and appearances that can be obtained. Controlling color nuances remains a challenge even today. Therefore, it is necessary to develop processes that allow materials to be manufactured on demand according to their aesthetic properties, especially their color. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] EP3766997 [Patent Document 2] EP3822712 [Patent Document 3] WO2015061817 [Patent Document 4] CN110328371A [Patent Document 5] CN111992731A Summary of the Invention

[0010] BRIEF DISCLOSURE OF THE INVENTION One object of the present invention is to propose a method for manufacturing watch parts and / or watches that allows for greater aesthetic diversity, in particular in terms of shades, colors, tints and their combinations.

[0011] Another object of the invention is to propose a method for manufacturing a watch component and / or a watch, the composition of which can be determined according to the color, tint and shade expected of the final part.

[0012] Another object of the invention is to propose a method for manufacturing a timepiece component and / or a timepiece, in which the decorative motifs obtained by the composition of said timepiece component and / or timepiece are reproducible.

[0013] Another object of the invention is to propose a method for manufacturing a timepiece component and / or a timepiece, in which the decorative motifs thereof are obtained in aggregate and the structure of said timepiece component and / or timepiece remains homogeneous.

[0014] Another object of the present invention is to provide timepiece elements and / or timepieces of greater quality and / or aesthetic variety, especially in terms of shades, colors, tints and combinations thereof.

[0015] Another object of the invention is to propose a clock element and / or clock comprising decorative motifs obtained in an aggregate, the shape and color of which are reproducible from one piece to another, forming a homogeneous structure.

[0016] According to the invention, these goals, or at least some of these goals, are achieved in particular by the methods, timepiece elements and timepieces that are the subject of the independent claims and are detailed in the dependent claims.

[0017] This solution has the particular advantage over the prior art of being able to predetermine the composition of the elements and clocks according to the color and / or final shade to be obtained, with a greater variety than currently available. This solution also allows a high degree of reproducibility of the shape and color of the decorative motifs, while preserving the homogeneous structure of such clocks. [Brief explanation of the drawings]

[0018] An embodiment of the invention is illustrated in the following description, illustrated by the drawings in which: Figure 1: Examples of colorimetric curves for some gold alloys according to the present invention. Figure 2: Example of colorimetric curve as a function of mass percent of 5N gold FIG. 3: Example of distribution of different gold alloys in a rough sketch of a watch according to the present disclosure. Figure 4: Example of a color analysis model used in this method

[0019] Examples of embodiments of the present invention The method according to the present disclosure makes it possible to obtain watch components with juxtaposed colored shades, as well as watches containing such components, thus enabling the creation of a wide variety of patterns. The color or shade is directly related to the material from which the watch element is made and is not limited to surface coloring. The method according to the present disclosure makes it possible to arrange various precious materials, in particular some gold alloys, without mixing them. The method according to the present disclosure also makes it possible to obtain a wider variety of combinations compared to certain alloys already available on the market. Composite materials produced according to the method described herein may have different mechanical properties, particularly in terms of hardness. Composite materials produced according to the present disclosure also have specific aesthetic characteristics that are utilized as a priority in the context of the present disclosure.

[0020] For the purposes of this specification, the term "composite material" refers to a material obtained from sintering the mixed powders described herein under the conditions of the method. Since the method does not involve melting of these powders, the resulting composite material is not considered an alloy. Preferably, the different powders are each made from a precious metal, in particular gold, or an alloy thereof. The powders can be described as "mixed / mixed." Preferably, the mixed powder contains at least one gold.

[0021] In one embodiment, the watch element considered herein is manufactured based on at least one composite material, which can be combined with at least one other material, such as a composite material, pure gold, and / or an alloy, such as a gold alloy. Such other materials are referred to herein as separate materials. In such a configuration, the composite material remains distinct from the separate materials in the final product. The method of the present invention allows for the manufacture of composite materials, preferably a combination of several composite materials, and their assembly. This includes, in particular, a first selection step S1 of a first gold O1 in the form of a first powder P1 and a second material in the form of a second powder P2. According to a preferred embodiment, the second material refers to a second gold O2.

[0022] For purposes of this specification, "gold," e.g., first gold and second gold, can refer to pure gold or any gold-based alloy already available on the market. Accordingly, gold can refer to white gold, rose gold, gray gold, green gold, or red gold alloys. Preferably, gold as described herein refers to a material comprising at least 37.5% (9 ct), or even at least 75% (18 ct), 92% (22 ct), or even 100% (24 ct). Preferably, gold as described herein refers to an alloy of 18 carats or more, e.g., 18 or 24 carats. Gold as described herein can include elements other than gold, such as precious or noble metals including silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), scandium (Sc), ruthenium (Ru), osmium (Os), and iridium (Ir), non-precious metals including copper (Cu), titanium (Ti), tin (Sn), nickel (Ni), and aluminum (Al), or combinations thereof. Precious and non-precious metals can be used independently of each other in various grades, such as 9ct, 12ct, 18ct, or 24ct, or in other grades. Gold grades referred to herein refer to all gold grades from 1N to 5N. Non-exhaustive examples of gold and its compositions are defined below: White gold: 75% gold, 19% copper, 6% silver, White gold: 75% gold, 25% palladium or 25% nickel, Red gold: 75% gold, 25% copper, Pink gold: 75% gold, 20% copper, 5% silver, Green Gold: 75% gold, 25% silver.

[0023] In this selection step S1, one or more additional materials Mi different from the first gold O1 and the second material can be selected. The additional materials can be independently selected from the above-mentioned precious or noble metals and / or non-precious metals. The additional material(s) Mi are in the form of a corresponding number of corresponding additional powders Pi.

[0024] The method comprises a first stage S2 of mixing a first powder P1 and a second powder P2, and, if applicable, additional powder(s) Pi, to produce a first homogeneous mixed powder PM1.

[0025] The first gold O1, the second material, and any additional materials are selected according to their properties, i.e., their composition, and mixed in predetermined proportions, as explained in more detail below, where the composition and proportions of the different golds are determined by their mass percentages and are predetermined according to the expected final color of the watch.

[0026] The watch component may contain only one composite material, in which case the watch component has a uniform color corresponding to the composite material, which may differ from the usual color corresponding to the commercially available alloy.

[0027] According to a more advantageous embodiment, the watch component comprises a composite material combined with another material. To this end, the method allows the first mixed powder PM1 to be combined with other powders already available on the market. For example, a separate material Md in powder form Pd can be placed together with the first mixed powder PM1 such that the color Cd of the separate material Md differs from the color C1 of the composite material A1 obtained from the first mixed powder PM1. In this case, the color Cd corresponds to the already existing color, while the color C1 is characteristic of the composition of the mixed powder PM1.

[0028] According to another embodiment, the watch component comprises two or more combined composite materials. To this end, the method comprises at least one further selection step and one further mixing step as described above, and possibly the addition of additional materials, to produce at least one composite material of a color different from the color of the composite material resulting from the first selection step S1 and the first mixing step S2. The resulting mixed powder(s) are not limited in number or color. For example, all shades between white gold and rose gold can be obtained with a corresponding number of mixed powders.

[0029] Thus, the method according to the present invention may comprise at least one second selection step S1' of the second first gold O1' and at least one second second material, respectively in the form of a second first P1' and at least one second second P2' powder, and one or more optionally present second additional materials Mi', in the form of a corresponding number of additional second powders Pi'. In an advantageous configuration, said second second material refers to a second second gold O2'. The method also comprises at least one second mixing step S2' of said second first P1' and second P2' powders, and, if applicable, one or more additional second powders Pi', to produce at least one second mixed powder PM2.

[0030] It will be understood that more than two different golds can be selected and mixed if desired, particularly to obtain very specific shades. For example, white gold, pink gold, and red gold can be mixed, or pink gold, green gold, and gray gold can be mixed, etc. Furthermore, mixing two or more golds does not preclude mixing them with one or more secondary materials or with one or more additional Mi materials.

[0031] Other selection steps and mixing of different golds can be performed to produce a corresponding number of different mixed powders MPi, which are then used to make watches. The number of mixed powders is not limited. A watch can be made using two, three, four, five or more different mixed powders. In addition, individual materials in powder form (which may not contain gold) can be used in combination with the mixed powders, as described above.

[0032] In the context of this specification, a mixed powder refers to a homogeneous powder containing at least two materials. Preferably, a mixed powder refers to a homogeneous powder containing at least one gold compound combined with at least one other material, such as a precious metal or alloy. Preferably, a mixed powder according to this specification refers to a homogeneous powder containing at least two different gold compounds. Homogeneous powder means that the different components are distributed uniformly, i.e., without concentration gradients. Thus, the color of the mixed powder is uniform. Furthermore, a homogeneous powder is defined by a predetermined, consistent particle size, e.g., more than 80%, more than 90%, or more than 95% of the particles have a size corresponding to a reference size. For example, the particles are micrometer-sized, i.e., have an average diameter of about 1 μm to 500 μm, or preferably 10 to 100 μm. Alternatively, the particles may be submicrometer-sized, i.e., have an average diameter of less than 1 μm. The average particle size of the powder can be adjusted depending on the material and / or the desired results.

[0033] The term "homogeneous" excludes multiphase or polyphase structures (e.g., including inclusions within a matrix), which result in a non-uniform mixture. The term "homogeneous" is synonymous here with single phase or monophase. The term "homogeneous" applies to all mixed powders, composites and additive materials, and combinations thereof.

[0034] For purposes of this specification, "homogeneous structure" refers to a material obtained from the method described herein based on one or more powders according to the present invention, whether they are juxtaposed or mixed. Although they may have different optical or physical properties, the juxtaposed powders result in a structurally homogeneous material, particularly with respect to their particle size. In particular, a homogeneous structure excludes particle sizes that exceed the average particle size of the powders used in its composition by 5%, 10%, or 20%. Homogeneous structure is herein synonymous with single-phase or single-phase structure.

[0035] The method includes a step S3 of individually placing the resulting powders (including at least one mixed powder PMi), regardless of their number, into a mold. Thus, the method includes a step S3 of placing a first mixed powder PM1 and at least one second powder. The at least one second powder can be a powder Pd of a separate material Md. The separate material Md can be selected from pure metals, particularly pure gold or precious metals, or gold alloys or alloys of precious metals that do not contain gold. Alternatively or additionally, the at least one second powder can be a second mixed powder PM2. The second mixed powder contains at least one gold. In this way, a combination of at least two powders can be formed, in which case at least one of the powders consists of a mixed powder as described above. It is understood that the mixed powder and the individual material powders all remain distinct from each other and are not mixed during the process. In other words, the different powders are juxtaposed, adjacent, or overlapped so as to retain their properties, and in particular their distinctive colors. Preferably, different powders are brought into contact with each other, thereby making it possible to create colored patterns, such as gradients or designs, or visual effects, such as camouflage or other patterns. This does not exclude the possibility that different powders can be separated from each other by partitions, for example, metal partitions that themselves create patterns. The powders are preferably arranged sequentially so as not to be mixed. They can each be arranged to form a layer (bed) of powder, or a pile of powder, or in a different arrangement, such as in the form of lines or geometric figures, or so as to appear reproducible but random. Depending on the requirements, one or more mixed powders can be used several times, for example to form several piles, or several lines, or in several layers alternating with other powders.

[0036] It is understood that the two juxtaposed powders are selected such that their expected colors at the end of the process differ from each other.

[0037] The mold used is suitable for sintering the powders placed in it. In particular, the mold is suitable for flash sintering or SPS (spark plasma sintering). The use of electrodes to heat the unmixed powder assembly allows for very short heating times and preserves the fineness of the particles.

[0038] Depending on the method used, the powders may be subjected to vibration or any other process to make them denser or more uniformly distributed, if necessary. Therefore, if this is done, it is important to ensure that the mixed powders do not mix during these processes.

[0039] The mixed powders are arranged relative to one another according to the color pattern to be obtained. In other words, a plan for the arrangement of the mixed powders can be created that allows powders identified by their color characteristics to be placed in predetermined positions and spaces within the mold. Thus, the pattern obtained is reproducible.

[0040] The method includes a step S4 of solid-state sintering under conditions that allow the assembly of powders placed in the mold to be produced into a monolithic part. The sintering is preferably flash or SPS sintering, performed at a sintering temperature Tfri and a sintering pressure Pfri determined so as not to melt any of the powders, particularly any of the mixed powders. For example, the melting temperature of gold at atmospheric pressure is approximately 1064°C. The melting temperatures of gold alloys are generally higher than this value. The sintering pressure Pfri can be a mechanical pressure in this case. Preferably, the sintering temperature Tfri is determined so as to remain below the lowest melting temperature of the mixed powders PMi under the sintering conditions. The appropriate sintering temperature Tfri can be evaluated as a function of the sintering pressure Pfri so as not to reach, exceed, or remain below the melting temperatures of the mixed powders at the sintering pressure Pfri. The temperature is also adjusted so as not to degrade structural elements incorporated in the powders, such as separating elements.

[0041] In one embodiment, the sintering temperature Tfri is less than 2000° C., or even less than 1500° C., or even less than 1000° C. For example, the sintering temperature is between 600° C. and 1600° C.

[0042] Sintering pressure Pfri is 20 to 180 N / mm 2 Between 50 and 100N / mm 2 Other pressure values ​​may be preferred depending on the components selected and / or the required quality of the final mechanical part.

[0043] After sintering, the mixed powders PMi result in a corresponding number of gold composites Ai, for example, a first mixed powder PM1 results in a first gold composite A1, a second mixed powder PM2 results in a second gold composite A2, etc.

[0044] The piece resulting from sintering is a single piece containing several separate materials bonded together. The materials can be independently selected from gold alloys, pure gold, and mixed powders, such as those described above. Thus, the part has different compositions in different locations. According to one embodiment, the part contains at least one composite material made from the mixed powders described above. They are produced in different colors, so that the mixed powders give the resulting part a number of different colors corresponding to the number of colors present in the composite materials used.

[0045] The method includes a step S5 of removing the integral part from the mold to obtain a demolded part, typically a pellet, preform, or rough sketch. The demolded integral part may correspond to the final component. However, the demolded part may require one or more subsequent operations to modify its shape to obtain the final component 1, in order to improve its quality or aesthetic appearance. For example, a grinding step S6 makes it possible to resize the demolded integral part. A machining step S7 can be conventionally performed to modify the integral part by any suitable technique, whether mechanical, laser, water jet, or any equivalent. One or more finishing steps S8 can also be envisaged. Other post-sintering transformations can be effected if necessary.

[0046] Alternatively or additionally, the integral part removed from the mold may be finished locally or over its entire surface by one or more decorative operations, such as satin finishing, beading, mirror polishing or glass bead blasting.

[0047] The properties of the first gold O1, the second material, particularly the second gold O2, and any additional material Mi, as well as their proportions in the corresponding mixture, are determined so that the resulting mixed powder PM1 produces a first composite material A1 of color C1 under the conditions of the process. The first color C1 is not necessarily identical to the color of the corresponding mixed powder PM1 before the sintering operation. It can also be difficult to accurately characterize the color of the mixed powder before sintering. Therefore, during the process, it is necessary to ensure that the mixed powder produced upstream produces a corresponding composite material Ai with the appropriate color. The properties of at least one second first gold O1' and second gold O2', and any additional second material Mi', as well as their proportions in the mixture, are also determined so that the resulting mixed powder(s) PM2 produces a second composite material A2—or some other composite material Ai—of color C2 and color Ci, respectively, under the conditions of the process. The second color C2 is different from the first color C1. The other colors Ci are also different.

[0048] Various Ai composites are fabricated and manufactured, each having a Ci color corresponding to a predetermined color. The various Ai composites represent gold composites combining at least one type of gold with another material. The gold can be selected from, for example, pure gold, white gold alloy, rose gold alloy, gray gold alloy, green gold alloy, yellow gold alloy, blue gold alloy, purple gold alloy, and red gold alloy. Typically, the other material refers to a precious metal or a precious metal alloy. It can also refer to non-precious metals and their alloys. Preferably, the various Ai composites represent gold composites combining at least two types of gold. The two types of gold can be independently selected from the above or other options. In this regard, the present specification encompasses a means for determining the composition of these Ai composites depending on the color to be obtained on the finished part. The method described herein may include one or more Se calibration steps, for example, consisting of selecting and mixing at least one type of gold and a second material to form a mixed powder, as described in steps S1 and S2 above, and determining its visual properties. The visual properties are determined, in particular, after a sintering operation corresponding to the conditions applied to manufacture the part. The visual properties of the mixed powders can be determined by any effective means, such as colorimetric tests.

[0049] According to one embodiment, the colorimetric test is * a * b * It can be based on a color space of type L * indicates brightness and can take values ​​from 0 to 100, and a * indicates the axis going from green to red, and b * indicates the axis going from blue to yellow. Figure 4 shows an example of such a color space used to characterize the color of the resulting pieces. However, other characterization systems can also be used.

[0050] The Se1 standardization step according to the present invention can consist of producing several mixed powders containing a given gold and a second material, or two specific golds, in various proportions, and subjecting them to a sintering operation, such as the sintering operation described above, so that the mixed powders produce the corresponding composite materials and exhibit their color after removal from the mold. * and b * An example of a calibration curve with values ​​such as those above is shown below: 75% Pd150 / 25% 5N18 50% Pd150 / 50% 5N18 25% Pd150 / 75% 5N18 100% 5N18 Here, the term 5N refers to a 5N red gold alloy and Pd150 refers to a nickel-free 18ct white gold alloy, both alloys sold by PX Group Inc. The composite materials used to manufacture the watch components or watches may correspond to one of these compositions or to an intermediate composition, depending on the desired color.

[0051] You can also create similar curves based on other golds. * and b * Other parameters can be determined besides L. In particular, the parameter L * , a * and b * can be determined individually, or in binary combinations in two-dimensional space, or all together in three-dimensional space.

[0052] According to one embodiment, the Se calibration step involves producing several mixed powders (each containing a variable mass percentage of elements), subjecting them to a sintering operation, such as the sintering operation described above, and, after demolding, determining the L * , a * Or b * This can consist of characterizing one or more of the parameters L. * , a * and b* The influence of one of the golds on one or the other of the golds can be accurately determined. Figure 2 shows an example of such a calibration curve, * It allows to determine the influence of 5N gold on the parameters.

[0053] The nature and proportion of gold alloys to be mixed in each mixed powder can thus be determined based on one or more calibration curves, such as those generated during one of the calibration steps Se1 and Se2 described above. Depending on the method used, extrapolation or interpolation of the calibration points allows for the determination of the nature and / or proportion of gold to be mixed to obtain an alloy of a given color. Depending on the method used, a computer-implemented predictive model may be used. In this case, the final color of the piece to be produced can be selected on an appropriate graphic interface. The model further allows for the determination of the composition of the corresponding mixed powder. Depending on the implementation, other parameters, such as the temperature and pressure conditions of the sintering operation, can also be suggested by the program. In other variants, input values ​​other than color can be implemented in the program. For example, hardness or density properties can be subject to secondary selection, and color can be adapted to other physical constraints, such as resistance to friction and scratches.

[0054] The Se1 and Se2 calibration steps described above may be based on materials other than gold, particularly additional Mi materials that may be used in the design of PMi mixed powders.

[0055] The calibration step(s) are preferably carried out on the calibration pieces produced according to the method described herein before the powder selection S1 and / or mixing S2 steps. In this way, the composition of the powder can be determined depending on the color to be obtained at the end of the process, thus avoiding the numerous trial and error steps required to obtain pieces of the desired color.

[0056] Additives may also be included in the composition of the mixed powder. Such additives may include metal oxides or pigments, which may also be the subject of a calibration curve.

[0057] According to a preferred embodiment, the mixed powder produced according to the methods described herein does not contain pigments. Preferably, the mixed powder consists solely of a mixture of two or more types of gold. Alternatively, the mixed powder according to this method consists solely of a mixture composed of at least two types of gold, precious or noble metals and / or non-precious metals, such as those mentioned above or alloys thereof. Alternatively, the mixed powder according to this method consists of or consists exclusively of two or more types of gold and precious or noble metals. Alternatively or additionally, the mixed powder according to this method does not contain more than one type of pure gold.

[0058] The gold involved in this method can be obtained in powder form. Alternatively, the method according to the present disclosure can include one or more gold atomization steps. For example, the method can include a step S1a of atomizing a first gold O1 to produce the first powder P1. It can also include a step S1b of atomizing the second material, e.g., a second gold O2, independently of the first gold, to produce the second powder P2. Alternatively or additionally, it can include a step S1i of atomizing additional materials, if any, to produce corresponding powder(s) Pi. The same atomization step can be repeated for one or more other powders. In particular, the method can include an atomization step S1a' of a second first gold O1' to produce a second first powder P1', an atomization step S1b' of a second second material, e.g., a second second gold O2' to produce a second second powder P2', and / or an atomization step S1i' of an optional second additional material Mi' to produce corresponding powder(s) Pi'. Preferably, the atomization steps S1a, S1a', etc. make it possible to control the properties of the powders obtained, in particular their particle size distribution, particle size distribution, etc. The atomization conditions can be the same for all powders or can vary depending on the materials used or the result to be obtained.

[0059] The method according to the present invention may also include one or more subsequent steps of transformation of the one-piece part removed from the mold. For example, it may also include a step S6 of adjusting the one-piece part removed from the mold to a desired thickness, a step S7 of machining, and / or a step S8 of finishing the one-piece part removed from the mold. Alternatively or additionally, the method described herein may include one or more steps during the operation, such as satin finishing, circular graining, mirror polishing, or glass blasting, depending on the characteristics of the watch to be obtained.

[0060] This specification also encompasses watch components obtained by the methods described herein. In particular, this specification encompasses at least one gold-based composite material composed of a first gold O1, at least one other material, such as a second gold O2, and one or more optional additional materials Mi, Mi', forming an inseparable whole. Typically, this specification encompasses watch components comprising at least two gold-based composite materials A1, A2, each composed of a first gold O1, O1', at least one other material, such as a second gold O2, O2', and one or more optional additional materials Mi, Mi', forming an inseparable whole. The watch components are characterized by the fact that the gold-based composite materials remain distinct from one another and have distinct colors C1, C2. In particular, the color of the composite materials A1, A2, or the color of at least some of the composite materials used, differs from the usual colors obtained with standard alloys. Preferably, a timepiece according to the present invention comprises three, four or more different A1, A2 composite materials (designed specifically for their color), said timepiece components being further characterized by the fact that said composite material(s) remain distinct from any of the separate materials they contain.

[0061] A timepiece component can refer to any element used in the construction of a timepiece. It can refer, for example, to a watch case, a bezel, a case back, a crown, a wound rotor, or parts of a watch strap, such as studs, links, pins, or clasps. Other timepiece components, particularly components forming part of a movement, can be manufactured according to the conditions described herein.

[0062] FIG. 3 shows an example of a rough sketch of a watch component containing several composites A1 and A2. In this case, the rough sketch shown in FIG. 3 has a first central alloy contrastingly bordered by a series of several different composites, thus creating a color gradient or tint from the center to the outer edge of the component. Two types of gold are shown here, with the mass percentage varying from 100% of one type of gold to 100% of the other. However, other configurations are possible. In another implementation, the different composites may be arranged in the form of concentric rings rather than bands. Alternatively, they may be arranged in a repeatable but seemingly random manner to create a specific visual effect. In this case, the central alloy is shown, but it could be replaced with pure gold or another pure metal, precious or non-precious.

[0063] The composite materials A1 and A2 obtained according to the methods described herein can be combined with standard alloys. In other words, the watch element can include one or more composite materials obtained from the mixed powders described herein assembled or combined with one or more standard alloys available commercially.

[0064] The present specification also encompasses a timepiece, e.g., a wristwatch, comprising at least one timepiece component as described herein. Preferably, the timepiece is designed so that the timepiece component is visible to the user. The visual effect may appear on a decorative element, such as a case or a portion of a case, or on other elements that constitute or are part of the timepiece, such as movement components. In addition, the visual effect may be reproduced on several components of the same timepiece, thus providing an enhanced aesthetic effect. For example, a link or a portion of a link of a bracelet may reproduce the visual effect of the case or another component. Alternatively or additionally, different components of the timepiece may have a single color obtained from one of the mixed powders produced according to the methods described herein, such that the different components have distinct colors from each other. It is understood that the various different configurations are not limiting and the present invention provides many possibilities. [Example]

[0065] Example 1 Different white gold (W) and rose gold (R) alloys were produced and the parameter L * , a * and b * It is characterized by colorimetry according to: Atomization of white gold alloy (W) with the following composition: Au750 PdCu150 Atomization of Rose Gold Alloy(R) with the following composition: Au750 Ag45 Cu205 White gold (B) and rose gold (R) alloys in powder form are weighed and mixed in a turbulence. The different compositions obtained are referred to as A1 to A5: TIFF2026502142000002.tif21170 Pellets are formed by sintering compositions A1, A2, A3, A4 and A5. The sintering is SPS (Spark Plasma Sintering) with the following characteristics: - Pressure between 5MPa and 200MPa - Sintering temperature between 300℃ and 1200℃ - Sintering time between 10 minutes and 2 hours. The pellets obtained were then removed from the mold and the color parameter L * , a * and b * Determine (Table 1). [Table 1] Figure 1 shows that the color evolution is proportional to the concentration of the two alloys A and R. Figure 2 shows the color evolution as a function of mass percent in 5N gold. * The coordinate progression is shown. The resulting piece is 18 carats.

[0066] Example 2 Atomization of 22 carat white gold alloy (C) with the following composition: Au925 Pd75 Atomization of 22 carat rose gold alloy (D) with the following composition: Au917 Cu83 White gold (C) and rose gold (D) alloys in powder form are weighed and mixed in a turbulence. The resulting composition is called A6 (Table 2): [Table 2] Pellets are formed by sintering composition A6. The sintering is SPS (Spark Plasma Sintering) with the following characteristics: - Pressure between 5MPa and 200MPa - Sintering temperature between 250℃ and 1300℃ - Sintering time between 10 minutes and 2 hours. The pellet thus obtained is removed from the mold. The resulting piece is 22 carats.

[0067] Example 3 Atomization of 18 carat and white gold alloy (A) with the following composition: Au750 PdCu150 Atomization of 22 carat rose gold alloy (D) with the following composition: Au917 Cu83 Atomization of non-precious grade 5 titanium alloy (E) of the following composition: Ti6Al4V. White gold (A) and rose gold (D) in powder form and titanium (E) alloy are weighed and mixed in a turbulence. The resulting composition is called A7 (Table 3): [Table 3] The amounts of alloys (A), (D) and (E) must comply with the following formula (E1): (E1):VmA x %A + VmD x %D + VmE x %E≧ 75% where VmA, VmD and VmE refer to the mass percent of precious metal in alloys A, D and E, respectively, and %A, %D and %E refer to the mass percent of alloys A, D and E in the piece, respectively. Thus, the final piece is 18 carats. Pellets are formed by sintering composition A6. The sintering is SPS (Spark Plasma Sintering) with the following characteristics: - Pressure between 5MPa and 200MPa - Sintering temperature between 350℃ and 1400℃ - Sintering time between 10 minutes and 2 hours. The resulting pellet is removed from the mold. The resulting piece is an 18-carat gold / titanium composite. In each of the above examples, the extracted pellets can be machined by any conventional means, such as milling on a 5-axis machine, to obtain watch components such as winding weights, cases, bezels, backs, crowns, or bracelet elements such as studs, links, pins, or clasps. The resulting components can be decorated by one or more satin-finishing, beading, mirror-polishing, or glass-beading operations.

[0068] The method for manufacturing at least one composite-based watch component (1) according to the present specification, including a composite material of 18 carats or more, can be characterized by one or more of the following elements:

[0069] It comprises an initial S1 selection stage of at least one first gold (O1) in the form of a first powder (P1), a second material in the form of a second powder (P2), and optionally one or more additional materials (Mi) different from the first gold (O1) and the second material (in the form of a corresponding number of additional powders (Pi));

[0070] a first step S2 of mixing, in predetermined proportions, said first (P1) powder, said second (P2) powder and, if applicable, additional powder(s) (Pi) so as to produce a first homogeneous mixed powder (PM1),

[0071] at least one selection step of a separate material (Md) in the form of one or more powders (Pd) intended to be combined with said first mixed powder (PM1) without mixing therewith,

[0072] a step S3 of placing said first mixed powder (PM1) and said one or more powders (Pd) of separate materials (Md) in a mold (2) so as to form an assembly of at least two powders, said powders not being mixed with one another;

[0073] Step S4 of sintering, which is flash or SPS sintering performed at a sintering temperature (Tsini) and a sintering pressure (Psini) determined so that none of the powders (PM1, Pd) melts;

[0074] Step S5: Remove the piece obtained from the sintering step S4 to obtain a demolded piece.

[0075] The nature of the first gold (O1) and second material and any one or more additional materials (Mi), and / or the proportions of their mixing, can be determined so that said first mixed powder (PM1) is suitable for producing a first composite material (A1) of color (C1) under the conditions of said method, and so that said separate material (Ad) gives rise to a color (Cd) under the conditions of said method, such that the color (C1) of the first composite material is different from the color (Cd) of the separate material (Ad).

[0076] The second material can be second gold (O2), a noble metal other than gold, or a noble metal alloy that does not contain gold.

[0077] The separate materials (Md) refer to precious metals, alloys of precious metals or mixed powders suitable for producing composite materials under the conditions of the process.

[0078] The separate material (Md) may be a second mixed powder (PM2) containing at least one gold. The selection of the one or more separate materials (Md) includes a second selection step S1' of the second first gold (O1') and at least one second second material, respectively, in the form of a second first powder (P1') and at least one second second powder (P2'), and one or more optionally present second additional materials (Mi'), in the form of a corresponding number of second additional powders (Pi'), and a second selection step S1' of the second first powder (P1') and at least one second powder (P2'), and, if applicable, one or more second additional powders (Pi'), to produce at least one second mixed powder (PM2), wherein the nature of the second first gold (O1') and the second second material and any additional second materials (Mi') and / or their mixing proportions are determined such that, under the conditions of said method, said at least second mixed powder (PM2) is suitable for producing a second composite material (A2) of a color (C2) different from (C1).

[0079] The second second material refers to second gold (O2'), a precious metal other than gold, or an alloy of a precious metal that does not contain gold.

[0080] "Gold" refers to pure gold or gold alloys.

[0081] The additional material (Mi, Mi') may be selected from silver (Ag), platinum (Pt), palladium (Pd), osmium (Os), titanium (Ti), nickel (Ni), copper (Cu), aluminum (Al) and alloys thereof.

[0082] The first powder (P1), the second powder (P2), the second first powder (P1'), and the second second powder (P2') are 18 carats or 22 carats.

[0083] The first mixed powder (PM1) and the one or more powders of separate materials (Md) are arranged in step S3 to independently form one or more clusters, one or more lines, or several alternating layers.

[0084] The sintering temperature (Ts) is between 600℃ and 1600℃.

[0085] Sintering pressure (Ps) is 20 to 180 N / mm 2 is the mechanical pressure between

[0086] The method may also include one or more steps, including a step S1a of atomizing the first gold (O1) to produce the first powder (P1), a step S1b of atomizing the second material to produce the second powder (P2), and an atomization step S1i to produce corresponding powder(s) of the additional material (Pi), and a step S1a' of atomizing the second first gold (O1') to produce the second first powder (P1'), a step S1b' of atomizing the second second material to produce the second second powder (P2'), and a step S1i' of atomizing any additional second material (M1') to produce powder (Pi').

[0087] The method may also include one or more of the following steps to obtain the watch component: S6: adjusting the one-piece part removed from the mold to a desired thickness, S7: machining the one-piece part removed from the mold, S8: finishing the one-piece part removed from the mold, S9: decorating, including one or more operations of satin finishing, circular graining, mirror polishing or glass blasting.

[0088] The first color (C1) can be determined based on at least one calibration curve generated during at least one previous calibration step Se.

[0089] The calibration curves according to the present method make it possible to determine, via extrapolation or interpolation of the parameters measured on said at least one calibration curve and / or via a predictive computer program, the proportions of gold, the second material and any additional materials in the mixed powder and / or their percentages by weight, depending on the color (C1) to be obtained.

[0090] A timepiece component according to the present specification may be characterized by one or more of the following elements: it may comprise at least one composite material comprising a first gold (O1, O1') and at least one second material, as well as one or more optionally present additional materials (Mi, Mi'), and one or more separate materials (Md), forming an inseparable whole, said at least one composite material and said one or more separate materials (Md) remaining distinct from one another, said at least one composite material having a color (C1) distinct from said one or more separate materials (Md), such that their juxtaposition results in a visual effect, for example a color gradient or tint.

[0091] The at least one second material may be a second gold (O2, O2'), a noble metal, or a noble metal alloy that does not contain gold.

[0092] The one or more individual materials (Md) may be a precious metal, a precious metal alloy, or a composite material. The watch component may be selected from a case, a bezel, a case back, a crown, a winding weight, or an element of a watch band, such as a stud, a link, a pin, or a clasp.

Claims

1. 1. A method for manufacturing a watch component (1) based on at least one first homogeneous composite material (A1) of 18 carats or more and of a given color (C1), comprising the steps of: a first selection step S1 of selecting at least one first gold (O1) in the form of a first powder (P1), a second material in the form of a second powder (P2), and optionally one or more additional materials (Mi) different from said first gold (O1) and said second material, said additional materials (Mi) being in the form of a corresponding number of corresponding additional powders (Pi); a first mixing step S2 of mixing said first powder (P1), said second powder (P2) and, if applicable, said additional powder(s) (Pi) in predetermined proportions to produce a first homogeneous mixed powder (PM1); a step S4 of sintering, said sintering being a flash or SPS type sintering operated at a sintering temperature (Tf) and a sintering pressure (Pf) determined so as not to melt said first mixed powder (PM1), after which said first mixed powder (PM1) gives said at least one first composite material (A1) of color (C1), a step S5 of demolding the pieces obtained from the sintering step S4 to obtain demolded pieces; In a method comprising: The method, characterized in that the properties of the first gold (O1) and the second material and any one or more additional materials (Mi) and / or their mixing ratios are determined so that the first mixed powder (PM1) is suitable for producing a first composite material (A1) of color (C1) under the conditions of the method.

2. 2. The method according to claim 1, further comprising one or more calibration steps Se, which make it possible to determine the visual properties of said at least one first composite material (A1) as a function of its composition, such that the properties and said predetermined proportions of said first gold (O1), said second material and any one or more additional materials (Mi) for obtaining said predetermined color (C1) based on said one or more calibration steps Se are defined.

3. The method of claim 2 , wherein the one or more calibration steps are performed before the selecting step S1 and the mixing step S2.

4. 4. The method according to claim 1, further comprising a step S3 of selecting separate materials (Md) in the form of one or more powders (Pd) intended to be combined with the first mixed powder (PM1) without mixing therewith, and placing the one or more powders (Pd) of the separate materials (Md) in a mold (2) to form an assembly of at least two powders comprising the first mixed powder (PM1), with the proviso that in the assembly the one or more powders (Pd) and the first powders (PMi) are not mixed with each other, wherein the separate materials (Md) result in a color (Cd) that is distinct from the color (C1) of the first composite material (A1) after a sintering step S4.

5. 5. The method of claim 1, wherein the one or more calibration steps comprise mixing at least one gold and a second material to produce a mixed powder, subjecting the mixed powder to a sintering step to produce a composite material from the mixed powder, and then determining visual properties of the composite material.

6. The visual characteristic is L ＊ , a ＊ , b ＊ The method according to any one of claims 1 to 5, wherein the color is determined by a colorimetric test based on the color space of the mold.

7. The method according to any one of claims 1 to 6, wherein the second material refers to second gold (O2), a noble metal other than gold, or a noble metal alloy that does not contain gold.

8. The method according to any one of claims 1 to 7, wherein said separate materials (Md) refer to precious metals, precious metal alloys or mixed powders suitable for producing a composite material under the conditions of said method.

9. The separate material (Md) is a second mixed powder (PM2) containing at least one type of gold, and the selection of one or more separate materials (Md) is a second mixed powder (PM2) containing at least one type of gold, and the selection of one or more separate materials (Md) is a second mixed powder (PM2) containing at least one type of gold, and at least one type of gold, in the form of a second first powder (PM1') and at least one type of gold, in the form of a second second powder (PM2'), respectively, and one or more additional second materials (PM1') that may be present, and the additional materials (PM1') are in the form of a corresponding number of additional second powders (PM1'). and at least one second mixing step S2' of mixing said second first powder (P1') and at least one second powder (P2'), and, if applicable, one or more additional second powders (Pi'), so as to produce at least one second mixed powder (PM2), under process conditions resulting in a second composite material (A2) of a color (C2) different from the color (C1) of said first composite material (A1), said color (C2) being different from the color (C1) of said first composite material (A1).

10. 10. The method according to claim 9, wherein the color of the second composite material (A2) is predetermined and the nature and / or proportions of the mixture of the second first gold (O1′) and second second material and any additional second materials (Mi′) are determined based on one or more calibration steps Se to produce the color (C2) of the second composite material under the conditions of the method.

11. 11. The method according to claim 9, wherein the second material is a second gold (O2'), a noble metal other than gold, or a noble metal alloy that does not contain gold.

12. The method according to any one of claims 1 to 11, wherein gold means pure gold or a gold alloy.

13. 13. The method according to any one of claims 1 to 12, wherein said additional material (Mi, Mi') is selected from silver (Ag), platinum (Pt), palladium (Pd), osmium (Os), titanium (Ti), nickel (Ni), copper (Cu), aluminium (Al) and alloys thereof.

14. 14. The method according to any one of claims 1 to 13, wherein the first powder (P1), the second powder (P2), the second first powder (P1'), the second second powder (P2') have an 18 carat or 22 carat gold grade.

15. 15. The method according to any one of the preceding claims, wherein the first mixed powder (MP1) and the one or more powders of separate materials (DM) are arranged during step S3 according to a predetermined arrangement plan.

16. The method according to any one of the preceding claims, wherein the sintering temperature (Ts) is between 600°C and 1600°C.

17. The sintering pressure (Pfri) is 20 N / mm ２ to 180 N / mm ２ The method according to any one of claims 1 to 16, wherein the mechanical pressure is between 0.5 and 1.

0.

18. 18. The method according to any one of claims 1 to 17, further comprising one or more of the steps of: atomizing the first gold (O1) S1a to produce the first powder (P1); atomizing the second material S1b to produce the second powder (P2); and atomizing the additional material S1i to produce corresponding powder(s) (Pi); atomizing the second first gold (O1') S1a' to produce the second first powder (P1'); atomizing the second second material S1b' to produce the second second powder (P2'); and atomizing any additional second material (Mi') S1i' to produce powder (Pi').

19. The method according to any one of claims 1 to 18, further comprising one or more of the following steps to obtain said timepiece component: S6: Adjusting the integral part removed from the mold to a desired thickness; S7: Machining the integral part removed from the mold; S8: Finishing the integral part removed from the mold; S9: A decoration step including one or more of the following operations: satin finishing, circular graining, mirror polishing or glass bead blasting.

20. 20. The method according to any one of claims 1 to 19, wherein said at least one preliminary calibration step Se allows the establishment of at least one calibration curve adapted to determine the proportions of gold, the second material and any additional materials, and / or their percentages by weight in the mixed powder, as a function of the color (C1, C2) to be obtained, via extrapolation or interpolation of parameters measured on said at least one calibration curve and / or via a predictive computer program.

21. A timepiece component comprising at least one homogeneous first component (A1) of a colour (C1), said component (A1) comprising a first gold (O1, O1') and at least one second material and one or more optionally present additional materials (Mi, Mi') which form an inseparable and homogeneous whole, the properties of said first gold (O1) and said second material and any one or more additional materials (Mi, Mi') and their proportions being determined so that the colour (C1) corresponds to a predetermined colour in at least one calibration curve, and said at least one first composite material (A1) forms a predetermined pattern.

22. 22. A timepiece component according to claim 21, further comprising one or more distinct materials (Md) of a color (Cd), wherein said at least one first composite material (A1) and said one or more distinct materials (Md) remain distinct from one another, said at least one first composite material (A1) having a color (C1) that is distinct from the color (Cd) of said one or more distinct materials (Md), such that their juxtaposition produces a predetermined visual effect.

23. A timepiece component according to claim 21 or 22, wherein said at least one second material refers to a second gold (O2, O2'), a precious metal or an alloy of precious metals that does not contain gold.

24. A timepiece component according to any one of claims 21 to 23, wherein said one or more distinct materials (DM) refer to a precious metal, a precious metal alloy or a composite material.

25. The at least one composite material (A1) has the following composition: 75% Pd150 / 25% 5N18 50% Pd150 / 50% 5N18 25% Pd150 / 75% 5N18 100% 5N18 wherein the term 5N represents 5N red gold alloy and Pd150 represents 18 ct nickel-free white gold alloy; A timepiece component according to any one of claims 21 to 24.

26. White gold alloy (B) with a composition of Au750 PdCu150, or rose gold alloy (R) with a composition of Au750 Ag45 Cu205 in the following proportions: or a 22 carat white gold alloy of the composition Au925 Pd75 and a 22 carat rose gold alloy of the composition Au917 Cu83 in a mass ratio of 67 / 33; Alternatively, the alloy may comprise an 18 karat white gold alloy (A) of composition Au750 PdCu150, a 22 karat rose gold alloy (D) of composition Au917 Cu83, and a non-precious alloy of grade 5 titanium (E), wherein the weight percentages of the alloys are as follows: VmA x %A + VmD x %D + VmE x %E≧ 75% where VmA, VmD, and VmE refer to the mass percent of precious metal in Alloys A, D, and E, respectively, and %A, %D, and %E refer to the mass percent of Alloys A, D, and E, respectively, in the piece. is determined by A timepiece component according to any one of claims 21 to 25.

27. A timepiece component according to any one of claims 21 to 26, selected from a case, a bezel, a caseback, a crown, a wound rotor, or a strap element, such as a stud, a link, a pin or a clasp.

28. A timepiece comprising a timepiece component according to any one of claims 21 to 27.

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