Light-weight and robust component

Abstract

Component, characterized in that it comprises at least one porous core, comprising a first material or based on a first material, with a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material, and in that it comprises a surface coating comprising at least one layer comprising a second at least partially amorphous metallic material overmoulded at least on the at least one porous core.

Description

[0001] Lightweight and robust component

[0002] The present invention relates to a component, particularly outside the field of watchmaking. It also relates to a method of manufacturing such a component.

[0003] In many fields, a component must achieve numerous mechanical properties, sometimes contradictory. Among these sought-after properties, we can mention:

[0004] - Lightness;

[0005] - A very attractive appearance, free from defects;

[0006] - Robustness, to withstand external constraints, so that the component retains the same appearance over time, and more generally all of its mechanical properties over time.

[0007] In practice, existing solutions represent compromises between these properties. Typically, components are produced massively from a material that can be both light and hard. However, these existing solutions have limitations, and there is a need to identify new solutions that optimize the properties and / or appearance of components.

[0008] An object of the present invention is therefore to propose a solution for obtaining a lightweight and robust component, in an improved manner compared to the state of the art.

[0009] For this purpose, the invention is based on a component, characterized in that it comprises at least one porous core, comprising a first material or based on a first material, with a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material, and in that it comprises a surface coating comprising at least one layer comprising at least one second metallic material that is at least partially amorphous overmolded at least onto the at least one porous core. The invention is also based on a method for manufacturing a component, characterized in that it comprises the following steps:

[0010] Production of a porous core, comprising a first material or based on a first material, with a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material;

[0011] Overmolding of at least one layer comprising a second at least partially amorphous metallic material of a surface coating at least on the at least one porous core.

[0012] The invention is more precisely defined by the claims.

[0013] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of particular embodiments made without limitation in relation to the attached figures among which:

[0014] Figure 1 illustrates elementary lattice structures obtained by a first step of a method of manufacturing a component according to an embodiment of the invention.

[0015] Figure 2 illustrates elementary structures of the TPMS type (for the English name of Triply Periodic Minimal Surface) obtained by the first step of a method of manufacturing a component according to another embodiment of the invention.

[0016] Figures 3a and 3b illustrate the porous cores of a component resulting from the first step of the manufacturing process of a component respectively according to two variants of the embodiment of the invention. Figures 4a and 4b illustrate two views of the porous core of a component blank resulting from the first step of the manufacturing process of a component according to a third variant of the embodiment of the invention.

[0017] Figure 5 illustrates a diffractogram, obtained by X-ray diffraction, of an amorphous metal alloy based on Zr, overmolded on a component according to the invention.

[0018] The concept of the invention consists in proposing a component comprising a porous core, very light, but robust or resistant, covered by a surface coating comprising at least one layer comprising or based on or consisting of an at least partially amorphous metallic material, which provides advantageous properties to the component, including high corrosion resistance, anti-allergenic properties, while having a high surface hardness, which can be greater than or equal to 500 HV. The result is thus a component for which no compromise is necessary, since it combines both the maximum possible lightness with satisfactory robustness and hardness. In addition, advantageously, the surface condition of the surface coating is such that it has or can have a very attractive appearance. Such a coating is also particularly well suited to surface treatment or structuring.It is also possible to functionalize such a coating, for example using laser texturing, and / or to obtain surface conditions and finishes such as sandblasted, satin, or polished.

[0019] Furthermore, an at least partially amorphous metal material or alloy, in particular an amorphous metal material or alloy, has excellent forming properties and can therefore advantageously cover a porous core so as to form a component, for example by molding followed by rapid cooling. In view of the very low shrinkage of amorphous alloys during the molding steps, the surface of the component will correspond to that of the mold with minimal geometric modifications, and can thus have any texture from the mold surfaces, for aesthetic or technical purposes. As a note, the term at least partially amorphous or partially amorphous indicates that, for a component made of a material, the percentage of the quantity of material of said component in the amorphous state is sufficient for the component itself to have the characteristics specific to amorphous metals and metal alloys.

[0020] Figure 5 illustrates for example a diffractogram obtained by X-ray diffraction of an amorphous metal alloy based on Zr, overmolded on a component according to the invention. This diffractogram is characteristic of amorphous alloys with two maxima much wider than those known for crystalline alloys.

[0021] In particular, throughout the text, we will use the expression "based on a material" to designate the fact that said material is the main or majority element. In particular, we will use the expression "based on a material" to designate the fact, for example, of comprising at least 50% by weight of said material.

[0022] A method of manufacturing a component according to an embodiment of the invention will now be detailed.

[0023] The method first comprises a first step of producing a porous core, made of a first material or based on a first material, with a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material. The density of the porous core is thus particularly low compared to the density of the first solid material. The density considered is the overall or average density of the porous core.

[0024] This first step can be carried out by means of several variant embodiments of the method. According to a particular variant embodiment, the step of producing the porous core comprises a step of chemically etching a solid blank formed in the first material. In this first variant embodiment, the first step of the method therefore comprises a first sub-step of producing a solid blank of the core of the component, in the first material or based on the first material. The first step of the method then comprises a second sub-step of chemically etching the solid blank formed in the first material, to form as a result a porous core. Such a porous core can then be in the form of a foam, for example a metal foam.

[0025] According to another particular embodiment variant, the step of producing the porous core can be based on the formation of bubbles in a liquid metal which is then solidified in the form of metal foam.

[0026] According to yet another particular embodiment variant, the step of producing the porous core may be based on a technique of infiltrating a liquid metal into a porous body made of a molding material. After solidification of the metal, the molding material forming the porous body is removed.

[0027] According to yet another particular embodiment variant, the step of producing the porous core comprises an additive manufacturing step, to directly form a porous core in the first material or based on the first material. For example, the laser powder or powder bed fusion technique ("Power Bed Fusion" in English) makes it possible to produce a controlled architecture, with a precise structure and good definition of the pore opening and good control of the anisotropy.

[0028] In all cases, the porous core has a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first massive material. In other words, the porous core has a mass less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of that of the mass of a body which would occupy the same volume as that of the porous core of the component and which would be present entirely in the same first material, in a massive manner.

[0029] The porous core may have a multitude of aspects according to the invention. For example, it may be a porous core having a skeleton shape formed by a regular or irregular porous network, in particular of the lattice type, or the structures known by the acronym TPMS (for the English name of Triply Periodic Minimal Surface), or even alveolar, cellular, or trabecular structures. In particular, the porous core may for example be made of metal foam.

[0030] The porous core may be in a multitude of materials. For example, it may be a porous core comprising a first material or based on a first material in the form of a metal or a metal alloy, or a metal superalloy, in particular comprising one or more elements from among Fe, Mg, Al, Ti, Au, Pd, Pt, Ni, Si, and / or Co. This first material may also be an amorphous or partially amorphous alloy, or a ceramic, for example a ceramic based on alumina or zirconia.

[0031] According to an alternative embodiment of the porous core, the latter may be made of several different materials. Preferably, the porous core is based on a first material as described above, that is to say that the structure formed by this first material is that which has the greatest weight in the porous core as a whole, and preferably constitutes at least 50% by weight of the porous core. In an alternative embodiment with several materials, the porous core may comprise different materials organized in layers between the center of the porous core and the surface of the porous core.In this particular variant, the porous core is in all cases in a porous structure of several materials, and the density of the porous structure formed by all of said materials is less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the same structure which would be massive and integrally formed in said first material.

[0032] In this document, the density of the porous core corresponds to the average density of the skeleton as a whole formed by the porous core and not to the density of the first material or materials constituting the core. Thus, the density of the porous core is a function of the porosity or porosity rate of the porous core.

[0033] For this purpose, Figure 1 illustrates, as examples, elementary structures representing different lattice structures that can be used in this first step of producing a porous core. Figure 2 also illustrates several elementary structures representing TPMS structures that can be produced as part of the first step of the process.

[0034] According to an exemplary embodiment, the porous core may be a foam having a random structure, i.e. comprising pores whose positions and dimensions are random, in an irregular manner. According to another exemplary embodiment, the porous core may have a regular, non-random structure, for example of the three-dimensional network type (known for example as a “lattice”), having a structure forming a repetitive network. This is the case of the aforementioned lattice structures.

[0035] The structure can thus be chosen to obtain maximum porosity while offering high mechanical resistance.

[0036] According to an alternative embodiment, the porous core is designed not only to minimize the overall weight but also to fulfill one or more other functions. For example, it may be designed to achieve optimal mechanical strength in certain areas intended to undergo the highest stresses or high mechanical stresses. Thus, the structure of the porous core can best respond to these high stresses, by being adapted to withstand these high stresses, for example by a particular non-homogeneous distribution of the first material forming or included in the porous core, so as to form mechanical reinforcements in the areas concerned.Among the other mechanical functions that can be taken into account when designing the structure of the porous core, it is possible to provide shaped zones to absorb shocks, zones dedicated to the assembly of said component with other components, zones allowing the sealing of said component to be reinforced, or zones allowing the transmission of sound. Alternatively or in addition, it is also possible to provide flexible zones to allow elastic deformation of the component. These flexible zones can also be dedicated to the assembly of said component with other components.

[0037] In addition, the structure can be designed to optimize the adhesion of the surface coating formed from a layer of amorphous or partially amorphous metal alloy that will be added, as will be described later. For this, the structure of the porous core can be different near its surface, for example to promote such adhesion. For this, the porous core can comprise pores of smaller dimensions near its surface relative to its center, so as to have a surface geometry compatible with the technique of subsequent deposition of the surface coating, for example with the process of overmolding a second amorphous or partially amorphous metal material, in order to obtain a compact surface coating with an optimal thickness. It is also possible to produce a denser layer on the surface of the porous core relative to its center, with a given thickness, defined according to the desired properties.More generally, the porous core may therefore have a non-homogeneous structure, in particular having a difference between its center and its surface, in particular a non-homogeneous porosity. This difference may consist of a gradient in the size of the pores, which increases from the surface to the center. In particular, the surface of the porous core or a given layer of the porous core may be devoid of pores, or have very few pores. Additionally or alternatively, a possible layer may be formed on the surface of the core in order to constitute a skin making it possible to seal the pores present on said surface, or even near said surface. All or some of the porous core variants described above may naturally be combined.

[0038] The method then comprises a second step of depositing a surface coating, in particular comprising at least one layer comprising a second amorphous or partially amorphous metallic material. According to one embodiment, the second step of depositing the at least one layer of a surface coating is carried out by overmolding. The second amorphous or partially amorphous metallic material may be a metallic glass. In particular, the amorphous or partially amorphous material may be an at least partially amorphous metallic alloy comprising a metallic base formed from at least one metal among the elements Ni, Cu, Pd, Pt, Fe, Co, Ti, Nb, Zr, in particular an at least partially amorphous metallic alloy based on Ni, Cu, Pd, Pt, Fe, Co, Ti, Nb, Zr. In particular, the at least partially amorphous metallic alloy may be zirconium-based, or titanium-based, or nickel-based, or palladium-based, or platinum-based.

[0039] According to an alternative embodiment, the second step of depositing at least one layer of a surface coating of at least partially amorphous metal alloy comprises a sub-step of forming or overmolding, in particular hot or at high temperature, of the metal alloy in liquid form, followed by rapid cooling to obtain the metal alloy in amorphous or at least partially amorphous form.

[0040] According to another process variant, the procedure is carried out using the superplastic forming technique, which consists of heating the metal alloy in at least partially amorphous form above its glass transition temperature and below its crystallization temperature, then deforming it under low stress in a mold or impression, then cooling it before crystallization. A zirconium-based alloy, such as Zr55Cu30AI10Ni5, or a Pd-based alloy, such as Pd40Cu30Ni10P20, are suitable alloys, as is any alloy that can be obtained in at least partially amorphous form and has a wide temperature range available for implementing the process (in particular a significant difference between the glass transition temperature Tg and the crystallization temperature Tx, for example the alloy Zr55Cu30AI10Ni5 for which Tg = 409°C and Tx = 494°C, i.e. Tx-Tg = 85°C).In practice, the porous core and the metal alloy in at least partially amorphous form are placed in a mold, then the alloy is deformed in a Newtonian manner, or the alloy has become viscous, at the deformation temperature, then the mold and the component formed from the porous core and the at least partially amorphous overmolded alloy are rapidly cooled, then the component is demolded.

[0041] According to yet another process variant, the technique of injecting amorphous metal alloys is used, in particular by injection molding. In this case, the porous core is placed within an injection mold which forms a cavity, the alloy is melted at a temperature above the melting temperature, the liquid alloy is injected into the cavity between the walls of the mold and the porous core, for example by means of an injection piston, then the mold and / or the component formed from the porous core and the overmolded alloy are rapidly cooled in order to allow the latter to become amorphous or partially amorphous, and then the component is demolded. The metal alloys suitable for this process variant are preferably chosen from alloys based on zirconium, copper, nickel, iron, palladium, titanium, cobalt or hafnium, such as for example alloys of composition Zr58Cu16Ni13AI10Nb3, Zr41Ti14Cu13Ni10Be22 or Pd43Cu27Ni10P20.

[0042] Alternatively, any other process suitable for overmolding an amorphous or partially amorphous metal alloy onto a porous core may be implemented.

[0043] According to yet another embodiment variant, the second step of depositing a surface coating comprises a complementary sub-step making it possible to carry out, for example by a physical vapor deposition (PVD), or chemical vapor deposition (CVD), or atomic layer deposition (ALD) method, a deposit of a decorative layer consisting of or comprising a third material on the surface of the at least one layer consisting of or comprising the second at least partially amorphous metallic material. It may for example be a layer of a metal or a metallic alloy, for example of the Au, Ag, Pt, Pd type, with a thickness preferably between 500 nm and 20 pm.

[0044] In all cases, the second step of depositing a surface coating comprises at least one sub-step making it possible to produce a layer comprising a second metallic material that is at least partially amorphous overmolded onto the porous core.

[0045] Naturally, it is possible to combine the various embodiments described above to obtain a component whose coating is formed from at least one layer comprising an at least partially amorphous metallic material. For example, a first surface of the porous core may be coated according to one of these variants and a second surface of the porous core may be coated according to another of these variants. Preferably, care should be taken, during the manufacture of the component, to carry out the various process steps in such a way as to preserve the amorphous nature of the metallic alloy obtained, so as to avoid as much as possible any crystallization, and in particular partial or total crystallization, which would lead to the loss of certain properties of the amorphous alloy, such as for example corrosion resistance. Furthermore, the core is not necessarily coated in its entirety.For example, a first surface of the porous core may be coated with a layer comprising an at least partially amorphous metallic material, while a second surface of the porous core is uncoated, exposing the core.

[0046] In particular, it is thus possible to obtain a component, the outer surface of which is coated with an at least partially amorphous coating, for example an at least partially amorphous metal alloy, obtained by a first overmolding operation, or by any other variant described above, with the aim of protecting said component from external stresses, and a surface of the porous core of which is coated with a resilient material such as a polymer, at the end of a second overmolding operation, different from the first overmolding operation, with the aim of allowing shock absorption. Such a surface of the porous core may for example be an assembly surface, which is shaped to absorb shocks.In such an embodiment of a surface coating based on or comprising a resilient material such as a polymer, the surface coating may be produced by an overmolding process, for overmolding such a material as a polymer, in particular an elastomer such as a thermoplastic elastomer (TPE) or a fluoroelastomer (FKM, FFKM or FEPM), or a natural rubber (NR) or synthetic rubber (SBR, HNBR, EPDM), or a vinyl methylsilicone (VMQ) or a fluorosilicone (FVMQ). Alternatively, it may be a thermosetting elastomer.

[0047] Regardless of the embodiment variant, the manufacturing method advantageously makes it possible to create a transition zone at the interface between the porous core and the surface coating, which comprises the respective materials of the porous core and the surface coating nested together, to optimize the adhesion of the surface coating. Advantageously, this transition zone has a thickness greater than or equal to 50 μm.

[0048] Regardless of the embodiment variant, the manufacturing method may also comprise a step of filling the majority, or even all or almost all, of the pores of the porous core with a fourth material, which may or may not be part of the surface coating. This fourth material may be similar or identical to the second material of the surface coating, or be different from the second material. In such a case, we continue to define the porous core as the structure considered outside of its filling material. In a first case in which the fourth material is similar or identical to the second at least partially amorphous metallic material of the surface coating, the filling step may correspond to or form an initial sub-step of the second step of depositing a surface coating.

[0049] In the second case in which the fourth material is different from the second material of the surface coating, the filling step may form a separate intermediate step complementary to the second step of depositing a surface coating. The majority of the pores may be filled with a fourth material, while the pores of the porous core near the coated surface lie within the transition zone, which may have a thickness greater than or equal to 50 μm. The fourth material may for example be a resilient material such as a polymer. Thus, the component may for example comprise a porous core whose pores are all or almost all filled with an elastomeric material, and comprise a surface coated with a layer comprising or based on a distinct, metallic and at least partially amorphous material, optionally coated with a decorative layer.

[0050] Advantageously, such a pore filling step makes it possible to propose a component according to the invention which is further provided with a core comprising a material making it possible to dissipate shocks and thus to best preserve the skeleton formed by the porous core.

[0051] Furthermore, the second step of depositing a surface coating may comprise several sub-steps of producing a deposit of superimposed layers, resulting in a coating, in particular a surface coating, composed of several distinct layers. In such a case, these layers may be produced by the same embodiment variant among the variants explained above, or by different embodiment variants. Furthermore, these layers may be in the same material, said second material, or in different materials, said second material, then another material, etc. An advantage of this surface coating comes from the fact that it makes it possible to form a surface layer of at least partially amorphous metallic material.

[0052] Thus, in all cases, the second surface coating step makes it possible to form at least one at least partially amorphous metal layer, which may represent the surface coating on its own, and / or alternatively which may be covered by a decorative layer, in particular a thin decorative layer. In this latter variant, the second step of producing the surface coating thus comprises two distinct sub-steps, making it possible to deposit distinct and complementary materials.

[0053] As a note, the adhesion between the porous core and the surface coating is obtained by a natural mechanical adhesion resulting from the manufacturing process. According to an advantageous embodiment variant, the structure of the porous core, in particular at the level of its external surface intended to receive the surface coating, is shaped to optimize this adhesion. For this, it can include small pores, or even can have a solid surface, devoid of pores, or having very few pores.

[0054] In this regard, the manufacturing method may implement an optional intermediate step, of mechanical or thermal treatment or intermediate laser, the function of which is to densify the surface of the porous core, in particular by closing at least part of the pores on the surface of the porous core. This may for example be a sandblasting operation or using a laser, in particular a picosecond or femtosecond laser. Another intermediate treatment intended to promote good mechanical adhesion of the surface coating may consist of increasing the surface roughness of the porous core, which will allow the particles of the coating to anchor themselves in the surface irregularities. Yet another intermediate treatment may consist of cleaning or washing or plasma treatment or deposition of an adhesion promoter.More generally, the intermediate step can be provided to improve or control the surface of the porous core, in particular to optimize the adhesion between the porous core and the surface coating.

[0055] The manufacturing process can then include additional, optional treatments.

[0056] In particular, the method may implement an optional finishing step, in particular acting on the surface condition and / or the color of at least one layer of the coating, to give it a particular aesthetic appearance and optimize its final geometry, for example by erasing any surface defects. Such a step may also confer a particular functionality to the layer or to one of the layers of the coating. Such a step may be a step of laser rectification and / or texturing and / or polishing and / or micro-blasting and / or termination and / or decoration and / or coloring. It may be implemented mechanically and / or electrochemically and / or by optical means, for example by a picosecond or femtosecond laser. Different techniques may thus be combined in order to implement this finishing step.It thus makes it possible, for example, to obtain a component with a final surface condition such as textured, polished, sandblasted or satin, and / or with a specific color, or a combination of these conditions. This step can be carried out on the last of the deposited layers, but also intermediately on any of the layers constituting the surface coating, in the case where this surface coating comprises several layers. Care should be taken, during the manufacture of the component, to carry out these different optional steps in such a way as to preserve the amorphous or partially amorphous nature of the metal alloy obtained.

[0057] Figures 3a and 3b illustrate the application of the first step of the manufacturing method according to the invention. Figures 3a and 3b thus illustrate the porous core of a component, resulting from the first step of the method, according to two embodiment variants. In both cases, this porous core is produced by additive manufacturing in a first material which is titanium, in a mesh structure having mesh dimensions of 500 pm (figure 3a) and 200 pm (figure 3b) respectively. The corresponding porosity rate is 70% and 48% respectively. The density is 1.6 g / cm respectively 3 and 2.3 g / cm 3 As a side note, alternatively, the first material used could be magnesium Mg or aluminum Al or an Mg-based alloy or an AI-based alloy or a Ti-based alloy, replacing titanium, so as to obtain a porous core of the same structure even lighter. Indeed, with a Mg alloy with a density of 1.7 g / cm3 and a porosity of about 50%, it is possible to obtain an apparent density of 0.80 - 0.85 g / cm 3 of the porous core. It is also possible to consider the use of precious alloys based on gold Au, or palladium Pd, or platinum Pt, to obtain a precious metal component with a density significantly lower than that of the solid alloy. In addition, it is also possible to consider the use of a ceramic, such as an alumina or zirconia ceramic, to obtain a ceramic component with a density significantly lower than that of the said ceramic.

[0058] The invention relates more generally to a component, in particular a component, obtained by a manufacturing method according to the invention, which is naturally not limited to the preceding description.

[0059] Thus, the invention makes it possible to form any component, in particular any component, comprising a porous core comprising a first material, the porous core having a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first bulk material, and comprising a surface coating comprising at least one layer comprising or based on or consisting of a second material which is an at least partially amorphous metal, at least directly or indirectly arranged on the at least one porous core.

[0060] The surface coating comprises a second material, which may be identical to or different from the first material. The method described above has the advantage of being compatible with a large number of materials. For example, the first material of the porous core may be a metal or a metal alloy or a metal superalloy, in particular comprising one or more elements from among Fe, Mg, Al, Ti, Au, Pd, Pt, Ni, Si, and / or Co. This first material may also be an amorphous or partially amorphous alloy, or a ceramic, for example an alumina- or zirconia-based ceramic. In addition, the second material of the surface coating is an at least partially amorphous metallic material.

[0061] The surface coating is optionally designed to have a high level of hardness, as described above. It may thus have a surface hardness greater than or equal to 500HV, or even greater than or equal to 600HV, or even greater than or equal to 900HV. Alternatively or in addition, the surface coating is designed in particular to have an attractive shade, in particular a color or effect that cannot be achieved by the first material.

[0062] Finally, it may preferably have a high density. Thus, it comprises or consists of a second material and its density is advantageously greater than or equal to 90%, or even greater than or equal to 99% of the density of the second solid material.

[0063] Thus, advantageously, the surface coating or a layer of the surface coating may have a porosity rate less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%. As a note, the porosity rate has both aesthetic and functional consequences. Depending on the size of the defects resulting from the porosity, a polished surface will, for example, highlight the porosity, which may manifest itself by an irregularity in the reflection of the light fringe. In addition, the porosity may impair the functionality of the deposit and make it permeable, therefore ineffective as a protective barrier (thermal, chemical, etc.). It is therefore advantageous to obtain a surface coating deposit with the lowest possible porosity. Furthermore, the surface coating has sufficient thickness to contribute to the mechanical properties of the finished component.Advantageously, this thickness is between 20 and 700 pm, or even between 70 and 700 pm, or even between 100 and 700 pm, or even between 20 and 500 pm, or even between 70 and 350 pm, on the finished component after the coating has undergone a possible treatment. The deposition step can deposit at least one layer with a thickness greater than or equal to 20 pm, or even greater than or equal to 100 pm, or even greater than or equal to 250 pm, or even greater than or equal to 300 pm, or even greater than or equal to 350 pm. Advantageously, this thickness is less than or equal to 1.5 mm, so as not to make the finished component too heavy, not to overly complicate the manufacturing process, and to limit the risk of obtaining excessively high porosity of the surface coating. In addition, this surface coating can have a textured, polished, sandblasted or satin surface finish.After such a surface treatment, the resulting thickness of the surface coating is naturally less than that deposited: for example, in the case of a deposit with a thickness between 150 and 500 pm, polishing by mechanical means or by laser texturing can reduce this final thickness to approximately 80 pm.

[0064] As mentioned, the manufacturing method advantageously makes it possible to create a transition zone at the interface between the porous core and the surface coating which comprises said two interlocking materials, to optimize the adhesion of the surface coating. Advantageously, this transition zone has a thickness greater than or equal to 50 μm.

[0065] Furthermore, according to a particular variation of the invention, at least one portion or region of the component, in particular of the component, could comprise a porous core comprising a surface coating according to the invention, the remainder of the component being able to comprise any other architecture, in particular conventional. Thus, the invention also relates to a component which comprises a partially porous core, that is to say a core porous only in certain portions, or several porous cores connected together by one or more non-porous portions. Alternatively, the component could comprise a core consisting of several different porous portions, by the structure of their porosity and / or by the material(s) thereof. In all cases, the component therefore comprises at least one porous core. In other words, the core of the component can be wholly or partly composed of said at least one porous core.

[0066] By way of example, Figures 4a and 4b represent a component blank 1 provided with portions forming porous cores capable of being coated with a surface coating. These portions may for example prefigure flanks 2 or horns 3 of the component. These porous cores comprise a first material or are based on a first material, with a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material, and at least one layer of the surface coating, not shown, capable of being deposited comprises at least one second metallic material that is at least partially amorphous. As a note, the porous cores of these embodiments according to Figures 4a and 4b comprise solid, non-porous edges 5, to form reinforced zones at fragile locations.

[0067] Finally, the invention therefore makes it possible to combine two major objectives for a component, which were not achieved until now. It makes it possible to obtain both a lightweight component and a mechanically robust component, having an at least partially amorphous metallic surface layer, while being aesthetically attractive. It is also possible to functionalize the coating, for example using laser texturing, and / or to obtain surface conditions and finishes such as sandblasted, satin, or polished.

[0068] It appears that the invention could be implemented in many fields, for example automotive, aeronautics, space, medical, etc., for which it is useful to have light and robust components. The invention is not limited to the embodiments described, nor to the figures shown, and it can be implemented for any component outside of watchmaking.

Claims

CLAIMS 1. Component, characterized in that it comprises at least one porous core, comprising a first material or based on a first material, with a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material, and in that it comprises a surface coating comprising at least one layer comprising a second metallic material that is at least partially amorphous overmolded at least onto the at least one porous core.

2. Component according to the preceding claim, characterized in that the second at least partially amorphous metallic material is a metallic glass or an at least partially amorphous metallic alloy comprising a metallic base formed of at least one metal from among the elements Ni, Cu, Pd, Pt, Fe, Co, Ti, Nb, Zr, in particular an at least partially amorphous metallic alloy based on Ni, Cu, Pd, Pt, Fe, Co, Ti, Nb, Zr.

3. Component according to one of the preceding claims, characterized in that the second material is different from the first material, in particular the first material having a lower hardness than that of the second material.

4. Component according to one of the preceding claims, characterized in that said surface coating consists of at least one layer and optionally a decorative layer covering all or part of said at least one layer.

5. Component according to one of the preceding claims, characterized in that it comprises a fourth material, different or not from said second material, which occupies all or part of the pores of the at least one porous core.

6. Component according to one of the preceding claims, characterized in that the at least one layer of the surface coating has a surface hardness greater than or equal to 500HV, or even greater than or equal to 600HV, or even greater than or equal to 900HV.

7. Component according to one of the preceding claims, characterized in that the at least one layer of the surface coating has a porosity rate less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01% and / or a density greater than or equal to 90%, or even greater than or equal to 99% of the density of the second solid material.

8. Component according to one of the preceding claims, characterized in that the at least one porous core is in metal foam or is a skeleton formed by a regular or irregular porous network, in particular of the lattice, TPMS, alveolar, cellular, or even trabecular type.

9. Component according to the preceding claim, characterized in that the first material of the at least one porous core is a metal or a metal alloy or a metal superalloy, in particular comprising elements such as Fe, Mg, Al, Ti, Au, Pd, Pt, Ni, Si, and / or Co, and / or is an amorphous or partially amorphous alloy, or is a ceramic, in particular a ceramic based on alumina or zirconia.

10. Component according to one of the preceding claims, characterized in that the second material of the at least one layer of the surface coating is arranged at least on the at least one porous core, said surface coating or said at least one layer having a thickness of between 20 and 700 pm, or even between 70 and 700 pm, or even between 100 and 700 pm, or even between 20 and 500 pm, or even between 70 and 350 pm, and / or having a textured, polished, sandblasted or satin surface finish.

11. Component according to one of the preceding claims, characterized in that the at least one porous core has a non-homogeneous porosity, and / or has a porosity at its surface less than its porosity towards its center, and / or has pores at its surface of dimensions smaller than those of the pores towards its center or comprises a surface devoid of pores.

12. Method of manufacturing a component, characterized in that it comprises the following steps: Production of at least one porous core, comprising a first material or based on a first material, with a density less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material; Overmolding at least one layer comprising a second at least partially amorphous metallic material of a surface coating on the at least one porous core.

13. Method of manufacturing a component according to the preceding claim, characterized in that the step of producing at least one porous core comprises a step of chemical attack of a solid blank in the first material or based on the first material or an additive manufacturing step, forming at least one porous core in metal foam or in the form of a skeleton formed by a regular or irregular porous network, in particular of the lattice, TPMS, alveolar, cellular, or even trabecular type.

14. Method of manufacturing a component according to one of claims 12 or 13, characterized in that it comprises a final step of grinding and / or polishing and / or micro-blasting and / or decoration, to obtain a final surface condition of the textured, polished, sandblasted or satin type of the surface coating.

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