Method for manufacturing an element made of a metal alloy of a piece of jewellery or a timepiece

Abstract

The present invention relates to a method for manufacturing a metal element of a piece of jewelry or a timepiece, the method comprising the steps of: (a) shaping and agglomerating a solid composition comprising a metal powder and optionally an organic binder, the metal powder consisting of particles of an alloy selected from the group consisting of the following alloys: * gold alloys containing at least 583 wt‰ gold; * silver alloys containing at least 750 wt‰ silver; * platinum alloys containing at least 850 wt‰ platinum; shaping the mixture, forming an agglomerate of metal particles; (b) forming a metal element by sintering the agglomerate of metal particles on a support at a sintering temperature Tfri, the support having a coefficient of thermal expansion ΔV1, the agglomerate of metal particles having a coefficient of thermal expansion ΔV2, where 0.5*|ΔV2| ≤ |ΔV1| ≤ 1.5*|ΔV2| over a temperature range between * Tfri-200°C and Tfri for gold or silver alloys; * Tfri-400°C and Tfri for platinum alloys, the support and the agglomerate of metal particles being made of different materials.

Description

[0001]METHOD FOR MANUFACTURED A METAL ALLOY COMPONENT FOR JEWELRY OR WATCHMAKING ITEMS FIELD OF THE INVENTION The present invention relates to a method for manufacturing a metal alloy component. The component resulting from this method is intended for use in the luxury goods industry, for example, as a piece of jewelry or watchmaking. PRIOR TECHNIQUE The manufacture of objects based on precious metal alloys such as gold, silver, or platinum can be carried out in various ways. For example, objects can be formed by casting from the molten alloy or by additive manufacturing from metal particles. Alternatives to casting also include forging (rolling, thermal cycles), cutting, and machining. Some processes involve the formation of intermediate parts (agglomerate of particles) called green body and brown body, as well as a sintering step,according to the following steps: - formation of a green part from metallic particles and, for example, a binder, - formation of a brown part by heat treatment (debinding) of the green part, - sintering of the brown part. During the sintering step, the shrinkage of the particle agglomerate results in a loss of 10% to 20% of its volume. Ideally, the shrinkage is homothetic, but the friction of the part against the furnace floor in which the sintering takes place hinders the shrinkage. This results in a part where the portion not in contact with the furnace undergoes greater shrinkage than its lower portion. Consequently, the part exhibits heterogeneous properties. To overcome this drawback, the particle agglomerate (green or brown part) is placed on a sintering support.at the interface between the lower part of the workpiece and the furnace floor. The support thus allows for homothetic and controlled shrinkage. The sintering supports currently used are made of the same material as the workpiece being sintered, so that their deformation occurs at the same rate during sintering. US patent 2022 / 0274177 describes a method for sintering a green workpiece positioned on a support that can be made of the same materials as the green workpiece. EP patent 4086711 describes a sintering support for manufacturing a watch component, having a geometry configured to support the green workpiece. WO patent 2019 / 108995 describes a refining apparatus for the production of glass articles, using a platinum refining vessel and a zirconia cradle. US patent 4828495 describes a process for manufacturing a dental prosthesis from materials having, between room temperature and 600°C,a similar expansion. Document EP 4302903 describes a process for manufacturing parts by uniaxial compaction sintering. MANDAL S. et al. (“Correlation between the mechanical properties and the microstructural behaviour of Al2O3-(Ag-Cu-Ti) brazed joints”, Materials Science, Elsevier, October 15, 2004, vol. 383, no. 2, pages 235-244) described alumina ceramics with brazed joints based on a silver, copper, and titanium alloy. In the jewelry and watchmaking industries, components are generally made of precious metals. Using a support material of the same material as the part to be sintered leads to high manufacturing costs. Furthermore, recycling these metals forming the support material is expensive and cumbersome. Finally, it requires a large quantity of precious metals. It is therefore necessary to develop supports made of materials different from those used for manufacturing the parts to be sintered.to reduce the costs associated with manufacturing the metal component. Some inert materials have been used. These often have high melting points compared to certain precious metals, particularly gold alloys. Therefore, they are not suitable for achieving shrinkage that is simultaneous with that of the part being manufactured. Consequently, it is essential to use a support with a deformation adapted to that of the component to be sintered, especially at the sintering temperature. The present invention proposes to overcome the drawbacks of the prior art by using a support made of a non-precious material, having a coefficient of thermal evolution, around the sintering temperature, close to that of the part to be sintered. DESCRIPTION OF THE INVENTION The Applicant has developed a process for manufacturing a metal component, a piece of jewelry or a watch. During the process,A part to be sintered is positioned on a support allowing for homogeneous shrinkage with that of the part. More specifically, the present invention relates to a method for manufacturing a metal component, a piece of jewelry or a watch component, comprising the following steps: (a) shaping and agglomerating a solid composition comprising a metal powder and optionally an organic binder, the metal powder being made up of particles of an alloy selected from the group consisting of the following alloys: * gold alloys containing at least 583‰ by weight of gold, * silver alloys containing at least 750‰ by weight of silver, * platinum alloys containing at least 850‰ by weight of platinum, shaping the mixture forming an agglomerate of metal particles, (b) forming a metal component by sintering the agglomerate of metal particles on a support, at a sintering temperature Tfri, the support having a coefficient of thermal evolution ΔV1,the agglomerate of metallic particles having a thermal evolution coefficient ΔV2, with 0.5*|ΔV2| ≤ |ΔV1| ≤ 1.5*|ΔV2| over a temperature range between * T, fri -200°C and T fri for gold or silver alloys, * T fri -400°C and T friFor platinum alloys, the substrate and the metal particle agglomerate are made of different materials. The coefficient of thermal evolution corresponds to the coefficient of thermal shrinkage when the dimensions of the part decrease as the temperature increases, or to the coefficient of thermal expansion when the dimensions of the part increase as the temperature increases. Thus, the absolute value |ΔV1| indicates the evolution (shrinkage and / or expansion) of the substrate over a temperature range that depends on the nature of the alloy. In a particular embodiment, the manufacturing process may include intermediate or additional steps. These may include machining and / or grinding steps and / or other potential surface finishes on the particle agglomerate or on the metal element. In general,The manufacturing process does not include machining and / or finishing that may be performed on the metal part resulting from step (b). Machining and finishing of the metal part constitute post-manufacturing steps. Alloy. Advantageously, the metal powder of step (a) consists of particles of an alloy selected from the group consisting of: gold alloys comprising silver and copper; gold alloys comprising palladium and copper; gold alloys comprising copper; gold alloys comprising palladium, silver, and copper; gold alloys comprising platinum; gold alloys comprising silver and iron; gold alloys comprising silver,Copper and platinum; gold alloys containing titanium; gold alloys containing hafnium; gold alloys containing niobium; gold alloys containing chromium; gold alloys containing tantalum; silver alloys containing copper; platinum alloys containing copper; platinum alloys containing copper and gallium; platinum alloys containing gold; platinum alloys containing titanium; platinum alloys containing cobalt; and platinum alloys containing ruthenium. Alloys, particularly gold alloys, may contain additional elements (grain refiner, etc.), for example, at least one element selected from: titanium, hafnium, niobium, chromium, iridium, zirconium, tantalum, ruthenium, boron, iron, vanadium, cobalt, barium, yttrium, and mixtures thereof. Alloy compositions are given in parts per thousand, by weight. For example, the Au583-600Ag305-337Cu80-112 alloy contains, by weight, 583 to 600 ‰ of gold,305 to 337‰ of silver and 80 to 112‰ of copper, the total of the elements being equal to 1000. The Au585Ag320Cu95 alloy comprises, by weight, 585‰ of gold, 320‰ of silver, and 95‰ of copper, the total of the elements being equal to 1000 (585+320+95). When the alloy is gold-based (at least 583‰, or at least 14 carats), it advantageously comprises at least 750‰ of gold (18 carats), for example, at least 917‰ of gold (22 carats). This may include yellow gold, white gold, rose gold, or red gold. The gold-based alloy is advantageously chosen from the group consisting of: Au, 583-600 Ag 305- 337Cu80-112; Au583-600Ag250-282Cu135-167; Au750-765Ag145-175Cu75-105; Au750-768Ag110-140Cu110-140; Au750-765Ag75-105Cu145-175; Au750-765Ag30-60Cu190-220; Au750-768Ag30-60Cu190-220; Au750-766Pd45- 75 Cu 175-205 ; At 750-765 Ag 15-45 Pd 110-140 Cu 80-110 ; At 750-765 Ag 1-20 Pd 110-140 Cu 85-115 In 5-35 ; At 750-758Ag15-45Pd110-140Cu77-107; Au750-765Pd115-145Cu85-115In5-35; Au750-765Pd135-165Cu25-55Fe45-75; Au750-758Pd135-165Cu24-54Fe43-73; Au750-758Ag20-50Cu200-230; Au902-932Ag6-36Cu47-77; Au902- 932 Cu 68-98 ; and Au 902-932 Ag 40-70 Cu 13-43 The gold-based alloy is advantageously chosen from the group consisting of: Au 585 Ag 320 Cu 95 ; Au585Ag265Cu150; Au750Ag160Cu90; Au750Ag125Cu125; Au753Ag123.5Cu123.5; Au750Ag90Cu160; At 750 Ag 45 Cu 205 ; At 753 Ag 44 Cu 203 ; At 753 Ag 43,5 Cu 203,5 ; At 751 Pd 60 Cu 189 ; At 750 Ag 30 Pd 125 Cu 95 ; At 750 Ag5Pd 125 Cu 100 In 20 ; At 753 Ag 30 Pd 125 Cu 92 ; At 750 Pd 130 Cu 100 In 20 ; At 750 Pd 150 Cu 40 Fe 60; Au753Pd150Cu39Fe58 ; Au750Ag35Cu215 ; Au917Ag21Cu62 ; Au917Cu83 ; and Au917Ag55Cu28. When the alloy is silver-based, it advantageously comprises at least 900‰ silver, more advantageously at least 925‰ silver, advantageously Ag 913-943 Cu 57-87 or Ag 910- 940Cu60-90, more advantageously Ag928Cu72 or Ag925Cu75. When the alloy is platinum-based, it advantageously comprises at least 930‰ platinum, for example 953‰ platinum. In this case, it is advantageously chosen from the group consisting of: Pt 935-965 Cu 2-23 Ga 28-58 ; Pt 938-968 Cu 2-32 Ga 15-45 ; Pt 960-990 Cu 2-28 Ga 2-28 ; Pt 950- 980Cu13-44Ga1-33; Pt930-954Cu28-58Ga4-34; Pt938-968Cu32-62; Pt935-965Ru35-65. More advantageously, it is chosen from the group consisting of: Pt 950 Cu 7,5 Ga 42,5 ; Pt 953 Cu 17 Ga 30 ; Pt 975 Cu 12,5 Ga 12,5 ; Pt 964,5With 28,2 Ga 7,3 For 938,3 With 42,7 Ga 19 For 953 With 47 ; et Pt 950 Ru 50It can also be a platinum alloy comprising at least 950‰ platinum and 20 to 30‰ gold. Generally, in addition to their constituent elements (particularly those listed in the formulas above), alloys (gold, silver, or platinum) may include at least one additional element, such as a grain refiner, for example, at least one element chosen from: titanium, hafnium, niobium, chromium, iridium, zirconium, tantalum, ruthenium, boron, iron, vanadium, cobalt, barium, yttrium, and mixtures thereof. Preferably, the quantity of the additional element is between 30 and 2000 ppm by weight, relative to the total weight of the alloy, preferably between 30 and 1000 ppm. The presence of a grain refiner is optional. The metal powder particles of step (a) have a D50 particle size advantageously between 0.3 µm and 100 µm, more advantageously between 1 µm and 100 µm, advantageously between 1 µm and 80 µm, more advantageously between 1 µm and 50 µm.By "D50 advantageously between 0.3 µm and 100 µm", we mean that 50% of the metallic particles have a size between 0.3 µm and 100 µm. Particle size distribution corresponds to the average volume size of the particles, for example, the average diameter when the particles are spherical. Particle size distribution can be measured with any type of conventional instrument, for example, by laser diffraction (for example, a Mastersizer-type instrument). ®(from Malvern Panalytical). Thus, regardless of the particle shape, the particle size distribution corresponds to the diameter of the equivalent sphere diffracting in the same way as the particle. Binder: The solid composition of step (a) optionally includes an organic binder. The presence of an organic binder improves the formation of the metal particle agglomerate by providing greater mechanical cohesion between the metal particles. This binder can optionally be removed during a possible debinding step preceding the sintering of step (b). The binder is advantageously a polymeric organic binder. The binder is preferably chosen from the group consisting of: acrylic acid polymers; polyethylene glycol; cellulose acetate butyrate; nanocellulose; corn starch; sugar; polylactic acid; polyethylene; polypropylene; synthetic wax; natural wax; stearic acid; and mixtures thereof.The binder can notably be one of the Aquafuse binders. ® or Cleanfuse ®marketed by ExOne (Desktop Metal), or one of the C20 or DM925 binders marketed by Digital Metal. Generally, the organic binder is eliminated during heating of the metal particle agglomerate, preferably when a temperature of 400 to 650°C is reached. Thus, the presence of the organic binder does not influence the behavior of the metal particle agglomerate and its thermal evolution (shrinkage and / or expansion) at a temperature between (i) Tfri-200°C and Tfri for gold or silver alloys or (ii) Tfri-400°C and Tfri for platinum alloys. Preferably, the mass ratio between the binder and the metal powder is between 0.1:99.9 and 2.5:97.5 when the metal particle agglomerate is shaped by binder jetting in step a).When the agglomerate of metal particles is shaped by additive manufacturing by MoldJet® in step a), the mass ratio between the binder and the metal powder is advantageously between 2:98 and 10:90. The support on which the agglomerate of metal particles rests has a thermal evolution coefficient ΔV1, the absolute value of which |ΔV1| corresponds to 0.5*|ΔV2| ≤ |ΔV1| ≤ 1.5*|ΔV2| over a temperature range between * T. fri -200°C and T fri for gold or silver alloys, * Tfri-400°C and Tfri for platinum alloys, where |ΔV2| is the absolute value of the thermal evolution coefficient ΔV2 at the sintering temperature, T fri , of the agglomerate of metallic particles. Advantageously, the thermal evolution coefficient ΔV1 corresponds to 0.8*|ΔV2| ≤ |ΔV1| ≤ 1.2*|ΔV2| over a temperature range between * T fri -200°C and T fri for gold or silver alloys, * T fri -400°C and TfriFor platinum alloys, the coefficient of thermal evolution measures the relative decrease in at least one dimension, for example, the volume, of an object (agglomerate of metallic particles or substrate) when the temperature changes. As already mentioned, this can be the expansion or contraction (shrinkage) of the object under the effect of temperature. A dilatometer is preferably used for this purpose. The substrate is advantageously made of a material chosen from the group consisting of: copper; alloys comprising copper and tin; alloys comprising copper, nickel, and tin; alloys comprising copper and aluminum; steels; titanium alloys; superalloys; carbides; nitrides; cermets; shape memory alloys; geopolymers; and ceramic materials.Examples of ceramic materials include clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, and glass frits. Advantageously, the substrate is made of a material selected from the group consisting of: CuSn8; CuSn. 10 ; CuSn 15 ; CuNi9Sn6, for example from the Niclafor brand ® CuNi 15 Sn8, for example from the Pfinodal brand ®CuAl; SiO2; Al2O3; ZrO2; earthenware; and porcelain. The support may also be made of materials selected from the group consisting of: 316L steel; 17-4PH steel; tool steel; TiAl and TiAl6V4; particularly in the case of an agglomerate of high-melting-point gold alloy metal particles (melting temperature advantageously above 1300°C) or high-melting-point platinum alloy metal particles (melting temperature advantageously above 1400°C). Advantageously, the support is a copper alloy when the metal powder consists of particles of a silver alloy. Advantageously, the support is a copper alloy when the metal powder consists of particles of a platinum alloy. The support may be partially or fully densified prior to step (b). If it is partially densified, its densification can be continued, or even optionally completed, at the same time as that of the metal element.The substrate can be designed using numerical simulation tools to adjust its density and morphology, and thus adapt its thermal evolution coefficient. For example, the substrate can be produced using one of the following techniques: - ceramic machining, - pressing, particularly of unsintered ceramics, - metal additive manufacturing (MIM), - additive manufacturing by extrusion of a mixture of metal powder and binder, for example fused deposition modeling (FDM or FFF), - binder jetting, - additive manufacturing using MoldJet®, - gel casting, - lithography, advantageously stereolithography or DLP (Direct Light Processing), - three-dimensional printing using an ink, for example NanoParticle Jetting® from XJET technology, or - screen printing. A person skilled in the art will be able to select the appropriate techniques to obtain a substrate according to the invention.In practice, the support can be circular, elliptical, parallelepiped, flat, or even hollow or domed. It can have a shape complementary to that of the agglomerate of metal particles. Generally, the support has dimensions compatible with watch or jewelry components. Advantageously, the dimensions of the support are such that it fits within a circle with a diameter between 1 mm and 20 cm, preferably between 1 cm and 10 cm. A person skilled in the art will be able to choose the height of the support, for example, a height between 0.5 times and 10 times the height of the watch or jewelry component to be manufactured. In one embodiment, the support is machined before use. The agglomerate of metal particles is advantageously positioned on the support and can be positioned before step (b). Advantageously, the alloy is Au583-600Ag305-337Cu80-112 (preferably Au585Ag320Cu95) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support consisting of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi15Sn8; support consisting of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Au583-600Ag250-282Cu135-167 (preferably Au585Ag265Cu150) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au 750-765 Ag 145-175 Cu 75-105 (preferably Au750 Ag 160 Cu 90 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au 750-765 Ag 110-140 Cu 110-140 (preferably Au750 Ag 125 Cu 125 or At 753 Ag 123,5 Cu 123,5 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Au750-765Ag75-105Cu145-175 (preferably Au750Ag90Cu160) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support consisting of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support consisting of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl. 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Au750-765Ag30-60Cu190-220 (preferably Au750Ag45Cu205) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support is made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au750-768Ag30-60Cu190-220 (preferably Au753Ag44Cu2O3 or Au753 Ag 43,5 Cu 203,5 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn 10 , or CuSn 15 support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2, or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Au750-766Pd45-75Cu175-205 (preferably Au751Pd60Cu189) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Au750-765Ag15-45Pd110-140Cu80-110 (preferably Au750Ag30Pd125Cu95) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au 750-765 Ag 1-20 Pd 110-140 Cu 85-115 In 5-35(preferably Au750Ag5Pd125Cu100In20) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support consisting of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au 750-758 Ag 15-45 Pd 110-140 Cu 77-107(preferably Au 753 Ag 30 Pd 125 Cu 92 and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2, or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au 750-765 Pd 115-145 Cu 85-115 In 5-35(preferably Au 750 Pd 130 Cu 100 In 20 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support is made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au750-765Pd135-165Cu25-55Fe45-75 (preferably Au 750 Pd150 Cu 40 Fe 60 and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2, or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support is made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au750-758Pd135-165Cu24-54Fe43-73 (preferably Au 753 Pd150 Cu 39 Fe 58 and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2, or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au 750-758 Ag 20-50 Cu 200-230 (preferably Au750 Ag 35 Cu 215 and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2, or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Au902-932Ag6-36Cu47-77 (preferably Au917Ag21Cu62) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Au902-932Cu68-98 (preferably Au917Cu83) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Au 902-932 Ag 40-70 Cu 13-43 (preferably Au917 Ag 55 Cu 28 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support is made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Ag 913-943 Cu 57-87 (preferably Ag 928 Cu72 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support is made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Ag 910-940 Cu 60-90 (preferably Ag 925 Cu75 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Pt935-965Cu2-23Ga28-58 (preferably Pt950Cu7.5Ga42.5) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.Advantageously, the alloy is Pt938-968Cu2-32Ga15-45 (preferably Pt953Cu17Ga30) and the support is selected from the following group: support consisting of pure copper; support consisting of copper and tin, preferably CuSn8, CuSn. 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Pt 960-990 Cu 2-28 Ga 2-28 (preferably Pt975 Cu 12,5 Ga 12,5 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Pt 950-980 Cu 13-44 Ga 1-33 (preferably Pt964,5 Cu 28,2 Ga 7,3 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn 10 , or CuSn 15 support made of copper, nickel and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Pt 930-954 Cu 28-58 Ga 4-34 (preferably Pt938,3 Cu 42,7 Ga 19 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl 10 Ni5Fe4, CuAl 10 Fe5Ni5, CuAl 10 Fe3, CuAl7Si2ou CuAl 11 Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Pt 938-968 Cu 32-62 (preferably Pt 953 Cu47 ) and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi 15 Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2 or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; The support consists of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, grog), feldspar-type minerals, porcelain (e.g., bone china), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware. Advantageously, the alloy is Pt 935-965 Ru 35-65 (preferably Pt 950 Ru50 and the support is selected from the following group: support made of pure copper; support made of copper and tin, preferably CuSn8, CuSn10, or CuSn15; support made of copper, nickel, and tin, preferably CuNi9Sn6 or CuNi15Sn8; support made of copper and aluminum, preferably aluminum bronze, preferably CuAl9Ni3Fe2, CuAl10Ni5Fe4, CuAl10Fe5Ni5, CuAl10Fe3, CuAl7Si2, or CuAl11Fe5Ni5; support made of steel, preferably 316L steel, 17-4PH steel, or tool steel; support made of a titanium alloy, preferably TiAl or TiAl6V4; support made of superalloys, preferably Inconel ® 718 or Inconel ®626; support made of carbides, preferably tungsten carbide or tungsten-cobalt carbide; support made of nitrides, for example metal nitrides; support made of cermets, for example cermets based on a metal (advantageously nickel, molybdenum or cobalt) and a carbide, boride or oxide ceramic; support made of a shape memory alloy; support made of geopolymers, for example a geopolymer comprising silico-oxide (-Si-O-Si-O-), silico-aluminate (-Si-O-Al-O-), ferro-silico-aluminate (-Fe-O-Si-O-Al-O-) or aluminophosphate (-Al-OPO-) motifs; support made of ceramic materials, such as clays (bentonite, kaolinite, illite, ball clay, chamotte), feldspar-type minerals, porcelain (e.g. bone ash porcelain), enamel, glass frits, SiO2, Al2O3, ZrO2, or earthenware.In all embodiments of the invention, the shaping of the agglomerate of metallic particles is advantageously carried out by one of the following technologies: - binder jetting, - additive manufacturing by MoldJet®, - gel casting, - metal injection molding (MIM), - additive manufacturing by extrusion of a mixture of metal powder and binder, for example fused deposition modelling (FDM or FFF), and - lithography.In all embodiments of the invention, the support is advantageously produced using one of the following techniques: - ceramic machining, - pressing, particularly of unsintered ceramics, - metal additive manufacturing (MIM), - additive manufacturing by extrusion of a mixture of metal powder and binder, for example fused deposition modeling (FDM or FFF), - binder jetting, - additive manufacturing using MoldJet®, - gel casting, - lithography, advantageously stereolithography or DLP (Direct Light Processing), - three-dimensional printing using an ink, for example NanoParticle Jetting® from XJET technology, or - screen printing. Step (a) Step (a) employs a composition comprising (advantageously consisting of) a metal powder and optionally a binder.Any process for forming the composition between the metal powder and, optionally, the binder can be used. This composition can be prepared before the shaping process that leads to the formation of the metal particle agglomerate, by bringing the metal powder into contact with, optionally, the binder. This can involve the formation of a mixture by depositing the binder, in the form of molten wire, onto the metal particles, or by forming a mixture of the binder in solid form (for example, as granules or powder) and the metal powder. In another embodiment, this composition can be in the form of a slurry, for example, a more or less viscous paste. This composition can also be prepared during the shaping process that leads to the formation of the metal particle agglomerate, for example, in an additive manufacturing process for the metal component.A particular embodiment involves additive manufacturing by spraying a binder onto the metal powder: the binder is deposited onto a thin layer of metal powder, layer by layer. The shaping (two-dimensional or three-dimensional) of the metal particle agglomerate from step (a) is advantageously carried out in an additive manufacturing device or in a mold. Shaping in an additive manufacturing device is progressive because it is performed layer by layer, as the metal particle agglomerate forms.Shaping can be carried out using one of the following technologies: binder jetting, additive manufacturing with MoldJet®, gel casting, metal injection molding (MIM), additive manufacturing by extrusion of a mixture of metal powder and binder, for example, fused deposition modeling (FDM or FFF), and lithography. Shaping is advantageously carried out at a temperature between 20 and 300°C, and more advantageously between 50 and 150°C. For example, shaping can be carried out at room temperature (generally between 20 and 25°C). The presence of an organic binder can facilitate the handling of the metal particle agglomerate by improving its mechanical properties.Depending on the nature of the binder and / or how it is brought into contact with the metal powder, the process may include a binder crosslinking step. This is particularly relevant when the binder and metal powder form a powdery mixture. The process may include, especially in the case of additive manufacturing using MoldJet®, the following steps: cooling, drying, and solvent evaporation during the deposition of the metal paste. The agglomerate of metal particles exhibits mechanical properties and hardness that allow it to be handled. As previously mentioned, shaping the mixture generates the agglomerate of metal particles. Step (a') Advantageously, the process includes a step (a') consisting of thermally and / or chemically treating the agglomerate of metal particles before step (b).When a binder has been mixed with the metal powder in step (a), this thermal and / or chemical treatment is a debinding process that removes the binder. The process may include a binder crosslinking step prior to step (a'), advantageously by thermal means. This step facilitates the handling of the metal particle agglomerate. As already mentioned, debinding can be carried out thermally or chemically (for example, using a solvent that dissolves the binder). The thermal treatment (debinding if a binder is used) is advantageously carried out for 20 to 720 minutes, more advantageously 120 to 360 minutes. It can be carried out under oxygen. In a preferred embodiment, the thermal treatment (debinding if a binder is used) is carried out at a temperature between 300 and 800°C, more advantageously 500 to 700°C.A person skilled in the art will adjust the temperature according to the nature of the metal powder. The heat treatment can be carried out in an air-exposed furnace. The heat treatment is advantageously carried out according to the following sequence: - place the agglomerate of metal particles in the presence of oxygen, for example in an air-exposed furnace, at temperature T1 (generally between 18 and 25°C), - increase the temperature T1 until reaching a temperature T2 between 200 and 500°C (advantageously 400°C), preferably following a temperature ramp of 0.5 to 20°C / minute, advantageously 1 to 5°C / min, for example 2°C / min, - optionally, maintaining the agglomerate of metallic particles at temperature T2 advantageously for 10 to 240 minutes, more advantageously for 30 to 120 minutes, for example 60 minutes, - if necessary, increasing the temperature T2 until reaching a temperature T3 between 300 and 800°C (advantageously 500 to 650°C), preferably following a temperature increase of 0.5 to 20°C / minute, advantageously 1 to 5°C / min, for example 2°C / min, - maintaining the agglomerate of metallic particles at a temperature between 300 and 800°C (advantageously 500 to 650°C), advantageously for 10 to 360 minutes, for example 120 minutes. The optional step of maintaining the agglomerate of metallic particles at temperature T2 can optimize debinding by gradually releasing the binder.Heat treatment (debinding if a binder is used) is advantageously followed by cooling the agglomerate of metallic particles, for example, to ambient temperature (generally between 18 and 25°C). In a particular embodiment, chemical treatment (debinding if a binder is used) is carried out at a temperature of at least 20°C, advantageously at least 25°C. Thus, chemical treatment can be combined with simultaneous or subsequent heat treatment. Chemical debinding can be achieved by bringing the agglomerate of metallic particles into contact with a solvent for the binder (crosslinked or not), for example, an organic solvent. When the binder is only partially dissolved, heat treatment can be implemented to optimize debinding.In one embodiment, debinding yields a brown part free of binder and exhibiting superior mechanical properties compared to the agglomerate of metal particles before debinding. This step therefore reduces, or even eliminates, losses and the risk of cracking that can result from handling the agglomerate of metal particles before step (b) of sintering. Generally, step (a') is carried out at a temperature below the temperature Tfri, more advantageously between T. fri -200°C and T fri for gold or silver alloys, and between T fri -400°C and T friFor platinum alloys, the brown part (a consolidated and possibly debound agglomerate of metal particles) resulting from this heat treatment exhibits mechanical properties and hardness that allow it to be handled and machined using conventional machining methods, such as CAD / CAM (computer-aided design and manufacturing), but also tribofinishing or grinding. Step (b) Generally, the temperature of step (b) is higher than those of steps (a) and (a'). Step (b) consists of forming the metal part by sintering the agglomerate of metal particles (possibly in the form of a brown part) onto the support. The sintering of the agglomerate of metal particles in step (b) can be carried out under an inert atmosphere (advantageously argon or nitrogen) or a reducing atmosphere. It can be carried out in a mixture of reducing and inert gases. Advantageously, the sintering in step (b) is carried out in a furnace.In practice, the sintering of the agglomerate of metallic particles in step (b) is carried out at a temperature T. fri between 750°C and 1950°C. Sintering is advantageously carried out at a temperature (T friThe temperature range is: - 750 to 1100°C, more advantageously between 850 and 1060°C, for gold alloys; - 750 to 1100°C, more advantageously between 850 and 1000°C, for silver alloys; - 1100 to 1950°C, more advantageously between 1400 and 1850°C, for platinum alloys. The agglomerate of metal particles is sintered for a duration advantageously between 20 and 500 minutes, preferably between 20 and 300 minutes, more advantageously between 30 and 180 minutes. In general, sintering hardens the agglomerate of metal particles and thus consolidates and densifies it by reducing (or eliminating) the pores. In practice, the sintering step (b) is the one during which the agglomerate of metal particles undergoes the greatest shrinkage. It can lose between 15 and 20% of its volume.The support of the invention optimizes the homogeneity of the resulting metal element by behaving in the same way as the agglomerate of metal particles. Step (c) The process according to the invention may include an optional hot isostatic pressing (or CIC) step of the metal element, preferably after the sintering step (b). This step (c) is preferably carried out in an isostatic press comprising a chamber that can be heated and pressurized. Advantageously, the hot isostatic pressing step (c) is carried out at a temperature T. CIC , corresponding to 50%*T f ≤ T CIC ≤ 95%*T f , where T fis the melting point of the alloy particles that make up the metal powder in step (a). Hot isostatic pressing is advantageously carried out at a temperature between 500°C and 1800°C. Advantageously, hot isostatic pressing is carried out at a temperature between 1000°C and 1750°C when the metal powder comprises particles of a platinum-containing alloy, and more specifically between: - 1000°C and 1500°C when the alloy consists of platinum and copper or platinum, copper, and gallium; or - 1250°C and 1750°C when the alloy consists of platinum and ruthenium. Hot isostatic pressing is advantageously carried out under the pressure of an inert gas (preferably nitrogen or argon), preferably by subjecting the metal element to a pressure between 10 8 and 2.10 8P. Advantageously, the metal element is subjected to hot isostatic pressing for a period of between 20 and 180 minutes, preferably between 30 and 70 minutes. This step also improves the mechanical properties and hardness of the metal element, in particular by reducing its porosity and thus increasing its density. Advantageously, after this step, the element has a density greater than 99%, preferably 99.5%, and even more preferably 99.9%. This step also improves the machinability of the element. Metal element produced by the manufacturing process of the invention. The metal element produced by step (b) or (c) can be used without further treatment. It can also be machined using conventional machining methods, for example, turning, milling, drilling, boring, or using laser machining methods. It can also be subjected to a finishing step, in particular polishing.The process may include at least one post-treatment step (d) such as tribofinishing, sandblasting, machining, or pre-machining, etc. Thus, the metal element produced by the process according to the invention can be used in numerous fields, and more particularly in the luxury goods industry. The present invention also relates to a piece of jewelry or a watch comprising the metal element produced according to the process of the invention. The term "jewelry" refers to jewelry items (necklaces, pendants, chains, rings, earrings, bracelets, brooches, tiaras, and other jewelry), but also to ornaments, such as fashion accessories (cufflinks, money clips, hair clips, pins, etc.).By watchmaking article, we mean in particular watch cases, crowns, pushers, dials, metal watch bracelets, clasps, mechanical parts of a watch movement (oscillating weight, balance wheel, mainplate, bridge, etc.). DESCRIPTION OF FIGURES Figure 1 is a representation of the transformation of an agglomerate of metal particles positioned on a support, into a metal element according to an embodiment of the invention. DETAILED DESCRIPTION OF FIGURES With reference to Figure 1, assembly 10 represents an agglomerate of metal particles positioned on a sintering support. The agglomerate of metal particles is formed from a metal powder consisting of particles of a gold alloy (for example Au). 753 Ag 30 Pd 125 Cu 92), mixed with a polymeric organic binder. The mixture is first shaped by metal additive manufacturing. The substrate is made of copper and produced by lithography, then machined to adopt a shape complementary to that of the particle agglomerate. Assembly 10 undergoes heat treatment to remove the binder. After thermal debinding, the particle agglomerate is transformed into a brown part. Assembly 11 illustrates the brown part obtained after heat treatment, positioned on the substrate. Assembly 11 is then subjected to a sintering step in a furnace, for example under an argon / hydrogen atmosphere. Sintering is carried out, advantageously at a temperature of 950°C for 200 minutes. After this step, the brown part undergoes shrinkage, resulting in a loss of 15% to 20% of its volume. The substrate exhibits a shrinkage proportional to that of the brown part.Assembly 12 represents the metal element obtained after sintering, positioned on the support. Assembly 12 has a volume 15 to 20% smaller than that of assembly 11.

Claims

CLAIMS 1. A method for manufacturing a metal component, a piece of jewelry, or a watch component, comprising the following steps: (a) shaping and agglomerating a solid composition comprising a metal powder and optionally an organic binder, the metal powder being composed of particles of an alloy selected from the group consisting of the following alloys: * gold alloys containing at least 583‰ by weight of gold, * silver alloys containing at least 750‰ by weight of silver, * platinum alloys containing at least 850‰ by weight of platinum, shaping the mixture to form an agglomerate of metal particles, (b) forming a metal component by sintering the agglomerate of metal particles on a support, at a sintering temperature T fri, the support having a thermal evolution coefficient ΔV1, the agglomerate of metallic particles having a thermal evolution coefficient ΔV2, with 0.5*|ΔV2| ≤ |ΔV1| ≤ 1.5*|ΔV2| over a temperature range between * T fri -200°C and T frifor gold or silver alloys, * Tfri-400°C and Tfri for platinum alloys, the support and the agglomerate of metal particles being made of different materials.

2. A process according to claim 1, characterized in that the metal powder of step (a) consists of particles of an alloy selected from the group consisting of: gold alloys comprising silver and copper; gold alloys comprising palladium and copper; gold alloys comprising copper; gold alloys comprising palladium, silver, and copper; gold alloys comprising platinum; gold alloys comprising silver and iron; gold alloys comprising silver, copper, and platinum; gold alloys comprising titanium; gold alloys comprising hafnium; gold alloys comprising niobium; gold alloys comprising chromium; gold alloys comprising tantalum; silver alloys comprising copper; platinum alloys containing copper;platinum alloys comprising copper and gallium; platinum alloys comprising gold; platinum alloys comprising titanium; platinum alloys comprising cobalt and platinum alloys comprising ruthenium.

3. A process according to claim 1 or 2, characterized in that the mixture in step (a) comprises an organic binder selected from the group consisting of: acrylic acid polymers; polyethylene glycol; cellulose acetate butyrate; nano-cellulose; corn starch; sugar; polylactic acid; polyethylene; polypropylene; synthetic wax; natural wax; and stearic acid and mixtures thereof.

4. A method according to any one of the preceding claims, characterized in that the shaping of the mixture in step (a) is carried out in an additive manufacturing device or in a mold.

5. A method according to any one of the preceding claims, characterized in that the support is made of a material selected from the group consisting of: copper; alloys comprising copper and tin; alloys comprising copper, nickel, and tin; alloys comprising copper and aluminum; steel; titanium alloys; superalloys; carbides; nitrides; cermets; shape memory alloys; geopolymers; and ceramic materials. 6.A method according to any one of the preceding claims, characterized in that the support is made of a material selected from the group consisting of: CuSn8; CuSn. 10 ; CuSn 15 CuNi9Sn6; CuNi 15 Sn8; CuAl; SiO2; Al2O3; ZrO2; earthenware; and porcelain.

7. A process according to any one of the preceding claims, characterized in that the support is made of materials selected from the group consisting of: 316L steel; 17-4PH steel; tool steel; TiAl and TiAl6V4; in the case of an agglomerate of metal particles in a high-melting-point gold alloy, above 1300°C, or a high-melting-point platinum alloy, above 1400°C.

8. A process according to any one of the preceding claims, characterized in that the sintering of the agglomerate of metal particles is carried out at a temperature T fribetween * 750 and 1100°C, for gold or silver alloys, * 1100 and 1950°C, for platinum alloys.

9. A process according to any one of the preceding claims, characterized in that the sintering of the agglomerate of metal particles is carried out under an inert or reducing atmosphere.

10. A process according to any one of the preceding claims, characterized in that the sintering of the agglomerate of metal particles is followed by a hot isostatic compaction step carried out at a temperature between 500 and 1800°C, and in that the process comprises a step (a'), consisting of thermally and / or chemically treating the agglomerate of metal particles before step (b).

11. A method according to any one of the preceding claims, characterized in that the substrate is produced by means of one of the following techniques: - ceramic machining, - pressing, - metal additive manufacturing, - additive manufacturing by extrusion of a mixture of metal powder and binder, - binder spraying or binder jetting, - additive manufacturing, - gel casting, - lithography, - three-dimensional printing using ink, or - screen printing.

12. A method according to any one of claims 1 to 5 or 8 to 11, characterized in that the substrate is made of copper or steel and in that the metal powder consists of particles of a gold alloy.

13. A method according to any one of claims 1 to 5 or 8 to 11, characterized in that the substrate is made of a copper alloy and in that the metal powder consists of particles of a silver alloy. 14.A method according to any one of claims 1 to 5 or 8 to 11, characterized in that the support is made of a copper alloy and the metal powder consists of particles of a platinum alloy. A method according to any one of claims 1 to 5 or 8 to 11, characterized in that the support is made of copper or steel and the metal powder consists of particles of a gold alloy selected from the group consisting of: Au. 583-600 Ag 305-337 Cu 80-112 ; At 583-600 Ag 250- 282Cu135-167; Au750-765Ag145-175Cu75-105; Au750-768Ag110-140Cu110-140; Au750-765Ag75-105Cu145-175; Au750-765Ag30-60Cu190-220; Au750-768Ag30-60Cu190-220; Au750-766Pd45-75Cu175-205; Au750-765Ag15- 45 Pd 110-140 Cu 80-110 ; At 750-765 Ag 1-20 Pd 110-140 Cu 85-115 In 5-35 ; At 750-758 Ag 15-45 Pd 110-140 Cu 77-107; Au750-765Pd115-145Cu85-115In5-35 ; Au750-765Pd135-165Cu25-55Fe45-75 ; Au750-758Pd135-165Cu24-54Fe43-73 ; Au750-758Ag20-50Cu200-230 ; Au902-932Ag6-36Cu47-77 ; Au902-932Cu68-98 ; et Au902-932Ag40-70Cu13-43.

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