CH714234B1 - A method of manufacturing a part and a part for watchmaking or jewelry, with a surface comprising titanium colored by oxidation. - Google Patents

Abstract

The present invention relates to a method of manufacturing a part with a surface comprising titanium colored by oxidation, in which the following steps are carried out: providing an intermediate part (20) comprising a substrate (22) in a first material different from titanium and at least a portion of the intermediate piece being covered with a layer of titanium (24) application of a laser beam (30) on said layer of titanium (24), whereby this layer of titanium ( 24) is oxidized and the color of at least part of its surface is changed. Application to a part for watchmaking, jewelry or jewelry.

Description

Technical area

The present invention relates to a method of manufacturing a part, with a surface comprising titanium colored by oxidation. The present invention also relates to a part for watchmaking with a surface comprising titanium colored by oxidation. Such oxidation is generally carried out by surface treatment in the form of anodization or anodic oxidation, also called anodizing.

[0002] Such a part is marked on the surface, by one or more zones of a different color from pure titanium for various needs: to create purely aesthetic effects on the surface (marbling, designs, etc.) or marks for informational purposes such as letters, numbers, digits or other indicative symbols. Such symbols can constitute indexes or hour markers on a watch face, namely signs of various shapes which replace the numbers marking the hours.

[0003] The use of titanium in the fields of jewelry, jewelry or watchmaking is developing, in particular as long as the aesthetic aspects of pure titanium are modified to make it more attractive for those fields in which the appearance of products always plays a primary role.

[0004] According to another common use for titanium parts in medical or dental settings, the part has (in whole or in part) on the surface a color which serves as a “color code” depending on the use of the parts.

[0005] Each colored area may have a color different from the color of another area, or even each colored area may have a gradient varying in intensity (from the lightest to the least light) of the same color, again a gradient with varying shades of a given color.

State of the art

[0006] Document EP2548982 relates to titanium alloys, in particular alloys predominantly composed of titanium and further comprising a fairly low level of a precious metal. This gives not only mechanical properties and resistance to corrosion or other chemical attacks close to those of titanium and also an aesthetic appearance linked to the variety of colors of the alloy obtained which can range from green or blue to gray, in passing through pink or pale yellow. However, this solution provides a uniform color of the part, and the price of such a part remains high, even higher than for an identical part made of pure titanium.

[0007] There are various anodization techniques, in particular electrochemical techniques consisting in growing a porous and colored oxide layer on the surface of the titanium part.

We also know from the publication "From Art to Engineering" (Sarah O'Hana, Andrew J Pinkerton, Kalsang Shoba - Laser Processing Research Center, School of Mechanical, Aerospace and Civil Engineering and TheVirtualCompany, both from Manchester), the possibility of obtaining different shades on a titanium substrate by laser oxidation. In this case, the heat of the laser and the oxygen of the air carry out an oxidation of the titanium, the presence of these various oxides TiO and TiO2, (more generally TiOx) or even Ti2O and possibly Ti2O3 modifying the structure and the color of the substrate of titanium. However, mass titanium parts are expensive and therefore reserved for uses limited to high-end or luxury items.

[0009] However, the use of these surface-modified pure titanium parts or these titanium alloy parts remains reserved for objects whose high monetary value is not a major obstacle.

Brief summary of the invention

An object of the present invention is to provide a manufacturing process free from the limitations of known processes.

Another object of the invention is to provide the manufacture of a part having a surface appearance of titanium, with aesthetic effects due to a variation in the color of this surface, while having a production cost of the part reduced compared to the cost of a solid titanium part.

According to the invention, these goals are achieved in particular by means of a method of manufacturing a part with a surface comprising titanium colored by oxidation, in which the following steps are implemented: - providing a intermediate part comprising a substrate in a first material different from titanium and at least a portion of the intermediate part being covered with a layer of titanium - application of a laser beam on said layer of titanium, whereby this layer of titanium is oxidized and the color of at least part of its surface is changed. It is understood that the different color of at least part of the surface of the titanium layer compared to the color of pure Ti (color of the titanium layer before laser treatment), is due to the formation, under the effect of heat, of one or more titanium oxide (s), in general at least TiO and TiO2 and optionally Ti2O, and in general TiOx.

This solution has the particular advantage over the prior art of making it possible to obtain titanium surfaces colored according to the desired graphics, in one or more colors and / or tints, for a monetary value of the part. less than in the case of a solid part made of titanium.

A person skilled in the art prefers a priori to use a bulk substrate to carry out an oxidation operation by laser or anoxidation because the use of a titanium layer deposited on a substrate presents a risk of damage, or even of decohesion if it is subjected to high heat as during laser treatment.

However, the present applicant has been able to obtain, according to the part manufacturing process of the invention, parts covered with a layer of titanium colored by laser oxidation, which not only resist the laser treatment which creates the surface coloring, but these parts also have good resistance over time (resistance to aging).

In addition, a large choice of materials is possible for the substrate, whether metallic or non-metallic materials, which opens up many application perspectives depending on the limitations and / or constraints to be observed for the product to manufacture incorporating a part obtained according to the method according to the invention. For example, much lighter parts can be obtained with a plastic substrate, in particular a polymer (for example a polymer from the family of “industrial polymers”).

The present invention also relates to a part for watchmaking, jewelry or jewelry, comprising a substrate in a first material other than titanium and a layer of titanium covering at least a portion of said substrate, said layer of titanium comprising on at least part of its surface at least one titanium oxide TiOxde so that this part of the surface has a modified color compared to the color of the rest of the titanium layer. In other words, the part of the surface having a color different from that of titanium is oxidized, which means that this part of the surface has titanium oxide, in general at least TiO and TiO2 and possibly Ti2O, and generally TiOx.

In the present text, by piece of jewelry or jewelry is meant an object of adornment, in particular a setting for one or more stones (precious stones and / or semi-precious stones and / or ornamental stones, or pearls for the jewelry and any other decorative element for jewelry). Without limitation, such a piece of jewelry or jewelry corresponds to all or part (component) of one of the following objects: rings (solitaires, wedding rings), necklaces, pendants, earrings, tiaras, crowns, throne, statue, automaton, Fabergé eggs, with a stone for jewelry and with or without a stone for jewelry.

[0019] Thus, according to a preferred arrangement, such a part belongs to the group formed by dials, plates, bridges, hands, case components, middle parts, crowns, watch glasses, including sapphire crystals. , bracelet components, watch movement elements, watch trim elements and their components.

In the present text, the term "component" is understood to mean an element of an assembly forming in itself a functional part, this element being manufactured independently before being assembled with other elements to form said assembly. . For example, a component of the "escape" assembly is for example the escape wheel, the anchor or the pallet.

According to one possible arrangement, the titanium layer covers the entire intermediate part. In this case, it is therefore 100% of at least one (or even both) face (s) of the intermediate part which is covered with the layer of titanium. This titanium layer will receive the laser beam over all or part of its surface, according to one or more sets of parameters, to form one or more portions of the same color, or of different colors.

According to another possible arrangement, the titanium layer covers several separate portions, that is to say discrete portions, of the intermediate part. In this case, it is therefore less than 100% of at least one (or even both) face (s) of the intermediate part which is covered with the titanium layer which is continuous or discontinuous. This titanium layer will receive the laser beam over all or part of its surface, according to one or more sets of parameters, to form portions of the same color, or of different colors.

Brief description of the figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: FIG. 1 illustrates in perspective a part being manufactured according to the method of the invention, Figure 2 is a sectional view of the part of Figure 1 in direction II-II, FIG. 3 represents in views 3.a to 3.f the different steps of the method according to the invention in the case of a first embodiment, FIG. 4 represents in views 4.a to 4.d the different steps of the method according to the invention in the case of a second embodiment, FIG. 5 represents in views 5.a to 5.e the different steps of the method according to the invention in the case of a third embodiment, FIG. 6 represents in views 6.a to 6.g the different steps of the method according to the invention in the case of a variant of the first embodiment, using a bonding sub-layer under the titanium layer , FIG. 7 represents in views 7.a to 7.e the various steps of the method according to the invention in the case of a variant of the second embodiment, using a bonding sub-layer under the titanium layer , FIG. 8 represents in views 8.a to 8.f the different steps of the method according to the invention in the case of a variant of the third embodiment, using a bonding sub-layer under the titanium layer , FIG. 9 represents the final step of the method according to the invention for an alternative embodiment of the method according to the first, the second and the third embodiment of FIGS. 3 to 5, FIG. 10 represents the final step of the method according to the invention for an alternative embodiment of the method according to the variant of the first, second and third embodiment of FIGS. 6 to 8, FIG. 11 represents a wristwatch of which several parts have been manufactured according to the method of the invention and include a visual color mark, FIGS. 12 and 13 represent an example of implementation of the method according to the invention, for two types of different substrates, in order to illustrate the obtaining of different colors and / or tints.

Example (s) of embodiment of the invention

It should be noted that in these figures, an identical element shown in several figures always bears the same reference numeral. In addition, for reasons of clarity, it should be noted that the thicknesses of the various elements shown have been greatly exaggerated in the drawings so that they are not strictly to scale.

An example of manufacturing a part according to the invention is illustrated in Figure 1, with an intermediate part 20 in the form of a disc. This intermediate part 20 comprises a substrate 22 surmounted by a layer of titanium 24. In this example, FIG. 1 illustrates the step of treatment with a laser beam 30 coming from a laser source 32 making it possible to mark the intermediate part 20. More precisely, as can be seen in this FIG. 1, a first sign 41 (here the letter A) and a second sign 42 (here the letter B), have already been formed in different color renditions. Without departing from the scope of the present invention, these letters A and B could be replaced by another letter, or a symbol or any sign and more generally any graphic element. On the other hand, a third sign 43 shown in dotted lines (here the letter C) is being produced by applying the laser beam 30 which travels a path intended to cover the area of the surface of the titanium layer 24, which will correspond to the limits of this third sign 43.

If we refer to Figure 2, we see the laser beam 30 which is directed and touches a restricted area 243a of the area 243 of the titanium layer delimiting the sign 43. This restricted area 243a undergoes an elevation temperature as a function of the parameters of the laser beam 30, and in particular of its power, which leads to a modification of the structure of the material at least in this restricted zone 243a, with an oxidation of the titanium, which creates a change in color of the titanium layer, visible on the surface of this restricted zone 243a. Thus, by conducting the laser beam 30 on the titanium layer 24, the sign 43 is traversed so that the latter becomes apparent and visible to the eye by a color differentiation with the area of the surface of the titanium layer 24 which surrounds this sign 43 and forming a second predetermined zone 240 which remains unchanged in color.

In total, in the part thus obtained, not shown, there are on the titanium layer 24 colored areas (also called in the present text the first predetermined areas including in particular the area 243) formed by signs 41 to 43 and an uncolored zone (also called in the present text a second predetermined zone 240) formed of the surface of the titanium layer 24 which does not include (apart from) signs 41 to 43 (see the reference sign 240 on the figures 1 and 2).

We now refer to Figures 3 to 5 showing the steps of different embodiments of the manufacturing process of a part according to the invention, including the steps of obtaining the intermediate part 20 including the titanium layer 24 will be processed by the laser beam 30.

In Figure 3, there is shown a first embodiment of the manufacturing process of a part according to the invention. More specifically, Figures 3.a to 3.e show the production of the intermediate part 20, which is then processed by the laser beam 30 as illustrated in Figure 3.f.

In this first embodiment, to obtain the intermediate part, the following steps are implemented: supply of a substrate 22 in a first specific material different from titanium (FIG. 3.a), deposition of a sacrificial layer 26 over the entire surface of the substrate 22 (Figure 3.b), removing the sacrificial layer 26 by etching in at least a first predetermined zone 243 intended to form at least one colored zone; the sacrificial layer 26 remaining in the second predetermined zone 240 (FIG. 3.c); depositing a layer of titanium 24 over the entire surface of the substrate 22; the surface of this titanium layer 24 being distributed between said at least one first predetermined zone 243 and at least one second predetermined zone 240 for which the titanium layer 24 covers the sacrificial layer 26 (FIG. 3.d), and removal of the stack formed of the titanium layer 24 and of the sacrificial layer 26 in said at least one second predetermined zone 240 (FIG. 3.e). Then, during the marking step illustrated in FIG. 3.f, the laser beam 30 acts on all or part of the remaining predetermined portions of the titanium layer 24, according to what has been previously described in relation to FIGS. 1 and 2. It follows that the first predetermined zones 243, namely the zones of the substrate 22 for which the titanium layer directly covers the substrate 22 from the step illustrated in FIG. 3.c, are at least partially colored on the surface. of the remaining portions visible in Figure 3.e of the titanium layer 24.

FIG. 4 shows a second embodiment of the method of manufacturing a part according to the invention. More precisely, FIGS. 4.a to 4.c show the production of the intermediate part 20, which is then processed by the laser beam 30 as illustrated in FIG. 4.d.

In this second embodiment, to obtain the intermediate part, the following steps are implemented: - providing a substrate 22 in a first bulk material different from titanium (Figure 4.a), - deposition of a titanium layer 24 over the entire surface of the substrate 22, the surface of this titanium layer 24 being distributed between at least a first predetermined zone 243 intended to form at least one colored (or partially colored) zone and at least a second predetermined zone 240 (FIG. 4.b), - removal of the titanium layer 24 (FIG. 4.c) by etching in said at least one second predetermined zone 240 forming at least one zone of bare substrate, whereby there is retains the titanium in said at least one first predetermined zone 243 intended to form at least one colored (or partially colored) zone. Then, during the marking step illustrated in FIG. 4.d, the laser beam 30 acts on all or part of the remaining predetermined portions of the titanium layer 24, according to what has been previously described in relation to FIGS. 1. and 2. It follows that the first predetermined zones 243, namely the zones of the substrate 22 for which the titanium layer directly covers the substrate 22 from the step illustrated in FIG. 4.b, are at least partially colored on the surface. of the remaining portions visible in Figure 4.c of the titanium layer 24.

In Figure 5, there is shown a third embodiment of the manufacturing process of a part according to the invention. More specifically, Figures 5.a to 5.d show the production of the intermediate part 20, which is then processed by the laser beam 30 as illustrated in Figure 5.e.

In this third embodiment, to obtain the intermediate piece, the following steps are implemented: supply of a substrate 22 in a first specific material different from titanium (FIG. 5.a), application of a mask 28 on one face of the substrate 22 (FIGS. 5.a and 5.b), said mask 28 delimiting at least one opening 281 corresponding to a first predetermined zone 243 intended to form at least one colored zone or at least partially colored (such a mask is a layer deposited and then etched to form the openings or else a pre-existing perforated plate simply placed on the substrate 22 - for example such a mask 28 is made of stainless steel), deposition of a titanium layer 24 over the entire surface of the substrate 22 surmounted by said mask 28 (FIG. 5.c), the surface of this titanium layer 24 being distributed between said at least one first predetermined zone 243 for which the layer of titanium 24 directly covers the substrate 22 and at least one second predetermined zone 240 for which the titanium layer 24 covers the mask 28, removal of the mask 28, whereby (FIG. 5.d) the titanium is kept in said first predetermined zone 243 (two zones 243 visible in FIGS. 5.c and 5.d) intended to form at least one colored zone or partially colorful. Then, during the marking step illustrated in FIG. 5.e, the laser beam 30 acts on all or part of the remaining predetermined portions of the titanium layer 24, according to what has been previously described in relation to FIGS. 1. and 2. It follows that the first predetermined zones 243, namely the zones of the substrate 22 for which the titanium layer directly covers the substrate 22 from the step illustrated in FIG. 5.c, are at least partially colored on the surface. of the remaining portions visible in Figure 5.d of the titanium layer 24.

Reference is now made more specifically to Figures 6 to 8 showing all the steps of a variant of the first, second and third embodiments of the method of manufacturing a part according to the invention, including the steps of obtaining the intermediate part 20, the titanium layer 24 of which will be treated by the laser beam 30.

In the case of this variant, the main difference with respect to the embodiments previously described in relation to Figures 3 to 5 lies in the fact that said additional step is also carried out: an underlayer is deposited attachment 29 directly on the substrate 22 formed of the first bulk material, and this before the deposition of the titanium layer 24, whereby a stack formed of the substrate 22 covered with at least a portion of the surface of the substrate is obtained on the bonding sub-layer 29, itself covered with the titanium layer 24. In the case of this variant, a bonding sub-layer 29 is used under the titanium layer 24 to improve the mechanical strength properties, in particular thermomechanical between the substrate 22 and the titanium layer 24, with the aim of contributing to a better resistance and a better resistance of the titanium layer on the substrate 22 in particular during the treatment by laser beam 30. By aille urs, the above means, in the case of the variant of the first embodiment, that the bonding sublayer 29 is even deposited before and under the sacrificial layer 26 (see FIG. 6.c).

To return to each of these variants, the variant of the first embodiment of the manufacturing method according to the invention visible in Figures 6.a to 6.g comprises the following steps: supply of a substrate 22 in a first specific material different from titanium (FIG. 6.a), deposition of a bonding sub-layer 29 directly over the entire surface of the substrate 22 (Figure 6.b), deposition of a sacrificial layer 26 over the entire surface of the bonding sub-layer 29 (figure 6.c) removal of the sacrificial layer 26 by etching in at least a first predetermined zone 243 intended to form at least one colored zone (FIG. 6.d); depositing a layer of titanium 24 over the entire surface of the substrate 22; the surface of this titanium layer 24 being distributed between said at least one first predetermined zone 243 for which the titanium layer 24 directly covers the sacrificial sub-layer 29 and at least one second predetermined zone 240 for which the titanium layer 24 covers the sacrificial layer 26 (figure 6.e), and removal of the stack formed of the titanium layer 24, of the sacrificial layer 26 and of the sacrificial sublayer 29 in said at least one second predetermined zone 240 (FIG. 6.f). Then, during the marking step illustrated in FIG. 6.g, the laser beam 30 acts on all or part of the remaining predetermined portions of the titanium layer 24, according to what has been previously described in relation to FIGS. 1 and 2. It follows that the first predetermined zones 243, namely the zones of the substrate 22 for which the titanium layer 24 directly covers the sacrificial sublayer 29 from the step illustrated in FIG. 6.e, are at least partially colored on the surface of the remaining portions visible in Figure 6.f of the titanium layer 24

The variant of the second embodiment of the manufacturing method according to the invention visible in Figures 7.a to 7.e comprises the following steps: -provision of a substrate 22 in a first bulk material different from titanium ( figure 7.a), - deposition of a bonding sub-layer 29 over the entire surface of the substrate 22 (figure 7.b), - deposition of a titanium layer 24 over the entire surface of the sub-layer attachment 29 (FIG. 7.c), the surface of this titanium layer 24 being distributed between at least a first predetermined zone 243 intended to form at least one colored zone (or partially colored) and at least one second predetermined zone 240 (FIG. 7.c), - removal of the stack formed of the titanium layer 24 and of the sacrificial sublayer 29 (FIG. 7.d) by etching in said at least one second predetermined zone 240 forming at least one zone of bare substrate, whereby the titanium is kept in said at least one first predetermined zone terminated 243 intended to form at least one colored (or partially colored) zone visible in FIG. 7.d. Then, during the marking step illustrated in FIG. 7.e, the laser beam 30 acts on all or part of the remaining predetermined portions of the titanium layer 24, according to what has been previously described in relation to FIGS. 1. and 2. It follows that the first predetermined zones 243, namely the zones of the substrate 22 for which the titanium layer directly covers the substrate 22 from the step illustrated in FIG. 7.d, are at least partially colored on the surface. of the remaining portions visible in Figure 7.e of the titanium layer 24.

The variant of the third embodiment of the manufacturing method according to the invention visible in Figures 8.a to 8.f comprises the following steps: provision of a substrate 22 in a first specific material different from titanium (FIG. 8.a), application of a mask 28 on one face of the substrate 22 (FIGS. 8.a and 8.b), said mask 28 delimiting at least one opening 281 corresponding to a first predetermined zone 243 intended to form at least one colored zone or at least partially colored, deposition of a bonding sub-layer 29 directly on the mask, this bonding sub-layer 29 being placed directly on the surface of the substrate 22 facing the openings 281 (FIG. 8.c), deposition of a titanium layer 24 over the entire surface of the substrate 22 surmounted by said mask 28 and the bonding sublayer 29 (FIG. 8.d), the surface of this titanium layer 24 being distributed between said at least a first predetermined zone 243 for which the titanium layer 24 covers the bonding sub-layer 29 which covers the substrate 22 at the level of the openings 281 of the mask 28 and at least a second predetermined zone 240 for which the titanium layer 24 covers the bonding sub-layer 29 which covers the mask 28, removal of the mask 28, whereby (Figure 8.e) the portion of the titanium layer 22 (on the corresponding portion of the bonding sublayer 29) is kept in said first predetermined area 243 (two visible areas 243 in FIG. 5.c and 5.d) intended to form at least one colored or partially colored zone. Then, during the marking step illustrated in FIG. 5.e, the laser beam 30 acts on all or part of the remaining predetermined portions of the titanium layer 24, according to what has been previously described in relation to FIGS. 1. and 2. It follows that the first predetermined zones 243, namely the zones of the substrate 22 for which the titanium layer directly covers the sacrificial sublayer 29 from the step illustrated in FIG. 8.d, are at least partially colored on the surface of the remaining portions visible in Figure 8.e of the titanium layer 24.

It is understood from the above that in the present text, the term "colored" is understood to apply to the titanium layer 24, a color modified by the laser treatment, therefore a color modified with respect to the color. pure titanium, and in particular with respect to the color of the titanium layer 24. This titanium layer 24, deposited either on the substrate 22, or on the bonding sublayer 29 itself placed on the substrate 22 , can be obtained by different deposition techniques. In particular, this titanium layer 24 is obtained in particular by deposition of PVD type (physical vapor deposition).

The assessment of the use or not of a bonding sub-layer 29 and the nature of this bonding sub-layer 29 depends on the nature of the substrate 22 used and its compatibility for good performance. of the titanium layer 24 on the substrate 22.

Regarding the PVD deposition techniques that can be used, mention may be made of vacuum evaporation, cathodic sputtering including ion beam sputtering (IBS) or even cathodic sputtering. High power pulse magnetron (HIPIMS or HPPMS), molecular beam epitaxy (MBE), physical electron beam vapor deposition (EBPVD), pulsed laser ablation (PLD).

According to an alternative embodiment, illustrated in Figures 9 and 10, the preserved areas of the titanium layer 24 which are colored by laser treatment, namely the first predetermined areas 243, are set back from the surface of the intermediate part 20 (and possibly the final part), because they are housed in one (or more) hollow formed by a cavity or a groove, of the face of the substrate 22 intended to receive the titanium layer 24 (face top of the substrate 22 in Figures 9 and 10).

In the case of Figure 9, these first predetermined areas 243 of the titanium layer 24 are arranged directly on the material of the substrate 22, at the bottom of the hollow or hollows formed in this substrate 22. For this purpose, in In the case of the first embodiment of the method illustrated in FIGS. 3a to 3f, the hollows can be formed by an initial etching of the substrate 22 supplied in the step illustrated in FIG. 3a, or during the etching of the sacrificial layer illustrated in FIG. 3c with an etching step which continues so that the material removal extends in a part of the thickness of the substrate 22 in the extension of the first predetermined zone (s) 243. In the case of the second embodiment of the method illustrated in FIGS. 4a to 4d, the hollows can be formed by an initial etching of the substrate 22 supplied in the step illustrated in FIG. 4a. In the case of the third embodiment of the method illustrated in FIGS. 5a to 5f, the hollows can be formed by an initial etching of the substrate 22 supplied in the step illustrated in FIG. 5a, these hollows then having to be in correspondence with the openings. mask 29.

In the case of Figure 10, these first predetermined areas 243 of the titanium layer 24 directly cover the remaining portions of the bonding sub-layer 29 which are directly placed on the material of the substrate 22. It is therefore portions of the stack formed of the titanium layer 24 surmounting the bonding sublayer 29 which is located at the bottom of the hollow or hollows formed in this substrate 22. For this purpose, in the case of the variant of first embodiment of the method illustrated in FIGS. 6a to 6f or of the second embodiment of the method illustrated in FIGS. 7a to 7d, the hollows can be formed by an initial etching of the substrate 22 supplied at the step illustrated in FIG. 6a or 7a .. In the case of the variant of the third embodiment of the method illustrated in FIGS. 8a to 8f, the hollows can be formed by an initial etching of the substrate 22 supplied at the step illustrated in FIG. 8a, these hollows. hollow must then be in correspondence openings of the mask 29.

Thus, as seen in Figures 9 and 10, by the fact that the first predetermined areas 243 of the titanium layer colored according to the invention have a surface located back from the upper face of the substrate 22 , this creates an additional visual effect which is added to the color contrast between these zones 243 and the substrate 22.

According to a possibility not illustrated, the hollows have a depth equal to the thickness of the titanium layer 24 if no bonding sub-layer is used, or else equal to the thickness of the stack of the titanium layer 24 and the bonding sublayer 29. In this case, compared to FIGS. 9 and 10, the external face of the titanium layer 24 is flush with the face of the substrate 22 (in particular the upper face of substrate 22), therefore arrives at the same height as the face of substrate 22.

Thanks to this alternative embodiment, the titanium layer 24, or more precisely the first predetermined areas 243 of the colored titanium layer according to the invention, are not protruding or forming a protrusion on the surface of the intermediate piece 20, which prevents wear, or other damage such as scratches on these first predetermined areas 243.

In order to allow a laser treatment of the titanium layer 24 which is sufficient to modify the color but which does not disturb the resistance of this titanium layer 24 on the substrate 22 (or on the bonding sub-layer 29), the thickness range of the titanium layer 24 deposited on the substrate 22 (or on the bonding sub-layer 29) preferably ranges from 40 nanometers to 5 micrometers. According to another preferred arrangement, in particular for deposition of the titanium layer by PVD route, the thickness range of the titanium layer 24 deposited on the substrate 22 (or on the bonding sublayer 29) ranges from preferably 40 nanometers to 2 micrometers. According to another preferred arrangement, in particular for depositing the titanium layer on a metallic substrate, the range of thickness of the titanium layer 24 deposited on the substrate 22 (or on the bonding sublayer 29) will vary. from 0.7 to 1.7 micrometers.

The list of preferably possible materials for the substrate (in a "first material") is as follows: all metals other than titanium and their alloys (in particular brass and steel), ceramic materials, polymers (polymers industrial), glass, sapphire crystal, silicon and its alloys. It is also possible in particular to use a substrate consisting of a gemstone, namely a substrate of natural origin, whether it is a precious stone, a fine stone, or an organic stone, in particular belonging to the group formed of sapphire and diamond.

For a polymer substrate, the first material is preferably a polymer belonging to the group formed by polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polyamides (PA), polyimides ( PI), acrylonitrile butadiene styrene (ABS), poly (methyl methacrylate) (PMMA), polycarbonate (PC), and polyetheretherketone (PEEK).

The applicant company has carried out various conclusive tests, including those described below in connection with Figures 12 and 13.

The two embodiments of color marking of a titanium layer on a metal substrate illustrated in Figures 12 and 13, were produced under the following conditions:

The laser used is a fiber laser (family of solid-state lasers): this type of laser produces the laser beam by means of a "seed" laser and amplifies it in glass fibers to which energy is supplied via pump diodes. The wavelength is located in the infrared and is 1064 nanometers. The laser used is a fiber laser, pulsed type, with a maximum power of 20 Watts, IPG type YLP brand, adjusted with the following parameters: Pulse duration: 100 nanoseconds Frequency: 200 kHz Beam movement speed: 200 mm / sec Hatching distance: 10 microns (ie the positional offset of the beam between each passing line of the beam). The other parameters are as follows:

EXAMPLE 1 (FIG. 12) Brass substrate with a layer of titanium 1 micrometer thick, deposited by PVD of the cathodic sputtering type ("sputtering") on a galvanic nickel bonding sub-layer having a thickness of 5 micrometers. L1.1 4.2 11 L1.2 4.2 10 L1.3 4.2 9 L1.4 4.2 8 L1.5 4.2 7 L1.6 4.2 6 L2.1 3.6 11 L2.2 3.6 10 L2.3 3.6 9 L2.4 3.6 8 L2.5 3.6 7 L2.6 3.6 6 L3.1 3 11 L3.2 3 10 L3.3 3 9 L3.4 3 8 L3.5 3 7 L3.6 3 6 L4.1 2.4 11 L4.2 2.4 10 L4.3 2.4 9 L4.4 2.4 8 L4.5 2.4 7 L4.6 2.4 6

EXAMPLE 2 (FIG. 13) Steel substrate with a titanium layer 2 micrometers thick deposited by PVD of the cathodic sputtering type ("sputtering") directly on the substrate. A1.1 2.2 7 A1.2 2.2 6 A1.3 2.2 5 A1.4 2.2 4 A1.5 2.2 3 A1.6 2.2 2 A2.1 1.8 7 A2.2 1.8 6 A2.3 1.8 5 A2.4 1.8 4 A2.5 1.8 3 A2.6 1.8 2 A3.1 1.4 7 A3.2 1.4 6 A3.3 1.4 5 A3.4 1.4 4 A3.5 1.4 3 A3.6 1.4 2 A4.1 1 7 A4.2 1 6 A4.3 1 5 A4.4 1 4 A4.5 1 3 A4.6 1 2

In these two examples 1 and 2, the color range obtained on positions L1.1 to L4.6 and on positions A1.1 to A4.6 extends from violet (wavelength of 380 nm ) to pale red (wavelength about 650nm).

The possible color range for the titanium surface treated by anodizing extends from violet (wavelength of 380 nm) to red (wavelength of 780 nm).

Other types of laser can be used without departing from the scope of the present invention, in particular other crystalline lasers, whether lasers which operate continuously or lasers which operate in a pulsed regime.

The method according to the invention is easily integrated into the production of a good number of parts, in particular before, but possibly after the assembly of the part in a more complex assembly.

Furthermore, the method according to the invention makes it possible to obtain on the same part colored portions whose color is different between distinct zones of this colored portion according to the method of the invention.

Thus, in Figure 11, there is shown an exemplary implementation for a wristwatch 50 of which several parts have been manufactured by resorting to the method of the invention and include one or more visual mark (s) ) or colored sign (s) 41 to 48, described below. In FIG. 11, these different colors do not conform to the final appearance but are represented schematically, in particular by hatching. Thus, on the bracelet 51, a link or metal segment 51a bears the signs 41, 42 and 43 respectively formed of the capital letters A, B and C. Furthermore, one of the lugs 52 of the middle bears a sign 44 in the form of star. An extension 53 of the wall of the case, along the middle band and which adjoins the head of a push button, bears a sign 45 in the form of a cross. A window 54 reveals a disc bearing a sign in the form of the number "15". On the dial 55, several signs have been obtained according to the invention, namely the written mention 47a, the indexes 47b having different geometric shapes, or the circular line 47c. Also, the needle 56 bears a mark 48 in the form of a wavy line. For example, the star-shaped sign 44 is obtained according to the alternative of the method described in relation to FIGS. 9 and 10 and forms a hollow sign with respect to the outer surface of the horn 52.

More generally, the part obtained according to the method of the invention belongs to the group formed of timepieces, components of a timepiece, pieces of jewelry, components of a timepiece. jewelry, pieces of jewelry and components of a piece of jewelry.

For an application in the watchmaking field, preferably the part obtained according to the method of the invention belongs to the group formed of dials, plates, bridges, hands, case components, middle parts, crowns, watch glasses, including sapphire crystals, bracelet components, watch movement parts, watch casing parts and their components.

Reference numbers used in figures

20 Intermediate piece 22 Substrate 24 Titanium layer 240 Second predetermined zone 243 First predetermined zone (sign 43) 243a Restricted zone during treatment by the laser 26 Sacrificial layer 28 Mask 281 Opening 29 Bonding underlayer 30 Beam laser 32 Laser source 41 Sign (letter A) 42 Sign (letter B) 43 Sign (letter C) 44 Sign (star) 45 Sign (cross) 46 Sign (number 15) 47a Sign (written mention) 47b Sign (index) 47c Sign (circular line) 48 Sign (wavy line) 50 Wristwatch 51 Bracelet 51a Bracelet link / segment 52 Horn 53 Extension of the middle band 54 Window and disc 55 Dial 56 Hand

Claims (15)

1. A method of manufacturing a part with a surface comprising titanium colored by oxidation, in which the following steps are implemented: - provision of an intermediate part (20) comprising a substrate (22) in a first material other than titanium, and the substrate comprising at least one portion covered with a layer of titanium (24) - application of a laser beam (30) on said titanium layer (24), whereby this titanium layer (24) is oxidized and the color of at least part of its surface is changed. 2. The manufacturing method according to claim 1, wherein the titanium layer (24) covers the entire intermediate part (20). 3. The manufacturing method according to claim 1, wherein the titanium layer (24) covers several separate portions of the intermediate part (20). 4. The manufacturing method according to claim 3, wherein the intermediate part (20) is obtained by the following steps: - supply of the substrate (22) in the first material, - deposition of a sacrificial layer (26) over the entire surface of the substrate (22), - removal of the sacrificial layer (26) by etching in at least a first predetermined zone (243) intended to form at least one colored zone; - deposition of the titanium layer (24) over the entire surface of the substrate (22); the surface of this titanium layer (24) being distributed between said at least one first predetermined zone and at least one second predetermined zone (240) for which the titanium layer (24) covers the sacrificial layer (26), and - Removal of the stack formed of the titanium layer (24) and of the sacrificial layer (26) in said at least one second predetermined zone (240). 5. The manufacturing method according to claim 3, wherein the intermediate part (20) is obtained by the following steps: - supply of the substrate (22) in the first material, - deposition of the titanium layer (24) over the entire surface of the substrate (22), the surface of this titanium layer (24) being distributed between at least a first predetermined zone (243) intended to form at least one colored zone and at least a second predetermined area (240), - removal of the titanium layer (24) by etching in said at least one second predetermined zone (240) forming at least one zone of bare substrate (22), whereby the titanium is kept in said at least one first predetermined zone (243) intended to form at least one colored zone. 6. The manufacturing method according to claim 3, wherein the intermediate part (20) is obtained by the following steps: - supply of the substrate (22) in the first material, - application of a mask (28) on one face of the substrate (22), said mask delimiting at least one opening corresponding to a first predetermined zone (243) intended to form at least one colored zone, - deposition of a titanium layer (24) over the entire surface of the substrate (22) surmounted by said mask, the surface of this titanium layer (24) being distributed between said at least one first predetermined zone (243) and at least a second predetermined zone (240) for which the titanium layer (24) covers the mask, - mask removal. 7. The manufacturing method according to one of claims 4 to 6, wherein an additional step is further carried out: a bonding sublayer (29) is deposited directly on the substrate (22) formed of the first material, and this before the deposition of the titanium layer (24), whereby a stack formed of the substrate (22) covered with the bonding sublayer (29) is obtained on at least a portion of the surface of the substrate (22), itself covered with the titanium layer (24). 8. The manufacturing method according to one of claims 1 to 7, wherein said titanium layer (24) has a thickness between 40 nanometers and 5 micrometers. 9. The manufacturing method according to one of claims 1 to 6, wherein said first material belongs to the group formed of metals other than titanium and their alloys, ceramics, polymers, glass, sapphire glass, gemstones, silicon and its alloys 10. The manufacturing method according to claim 7, wherein the first material is a polymer belonging to the group formed of polyvinyl chloride PVC, polyethylene PE, polypropylene PP, polyamides PA, polyimides PI, acrylonitrile butadiene styrene. ABS, poly (methyl methacrylate) PMMA, polycarbonate PC, and polyetheretherketone PEEK. 11. A method of manufacturing a part according to one of the preceding claims, wherein the part belongs to the group formed of timepieces, components of a timepiece, pieces of jewelry, components of. a piece of jewelry, pieces of jewelry and components of a piece of jewelry. 12. A method of manufacturing a part according to one of claims 1 to 10, wherein the part belongs to the group formed of dials, plates, bridges, hands, case components, middle parts, crowns, watch glasses, including sapphire crystals, bracelet components, watch movement parts, watch casing parts and their components. 13. Piece for watchmaking, jewelry or jewelry, comprising a substrate (22) in a first material other than titanium and a layer of titanium (24) covering at least a portion of said substrate (22), said layer of titanium (24) comprising on at least a part of its surface at least one titanium oxide TiOxde so that this part of the surface has a modified color compared to the color of the rest of the titanium layer (24). 14. Part according to claim 13, wherein said titanium layer (24) is housed in one or more hollows formed in one face of the substrate (22). 15. Part according to claim 13 or 14, said part belonging to the group formed by dials, plates, bridges, hands, case components, middle parts, crowns, watch glasses, including sapphire crystals, bracelet components, watch movement elements, watch trim elements and their components.