CH711958A2 - Element of coating in zirconia with selective coloration. - Google Patents

Abstract

The present invention relates to a portable object covering element (1) made of a first material, the first material being a ceramic material having a first color. The surface of said dressing element is at least partially treated so as to have at least one transformation provided with a color different from the first color.

Description

Description: [0001] The present invention relates to a cladding element and its manufacturing method made of zirconia-type ceramic whose coloration is selectively modified.

PRIOR ART

It is known portable objects such as watches, jewelry or bracelets that are partly made of ceramic. A known ceramic is zirconia ZrO 2.

Currently, it is possible to have a color of this zirconia by dyeing in the mass via white or black pigments or by dyeing the surface via a carburizing process transforming the surface of the zirconia to a certain depth. a layer of zirconium carbide. This layer of zirconium carbide imparts a platinum-colored glossy appearance to the cladding element.

In addition, it is known a nitriding process, similar to said carburizing process, to transform the surface of the zirconia to a certain depth in a layer of zirconium nitride conferring a glossy appearance of color close to gold yellow to the trim element.

However, currently, the colored zirconia parts are tinted uniformly, that is to say that the entire surface is tinted and not a zone. The disadvantage is that the current methods do not allow a variation of color and therefore the creation of reasons for aesthetic or functional purpose.

SUMMARY OF THE INVENTION

The present invention aims to overcome the disadvantages of the prior art by providing a ceramic cladding element and its manufacturing process that allow a color variation and thus the creation of patterns.

For this purpose, the invention relates to a covering element for a portable object made of a first material, the first material being a ceramic material having a first color, characterized in that at least one surface of said element dressing is at least partially treated so as to have a transformation provided with a coloring different from the first color.

This invention allows to have a trim element which is colored in depth, that is to say, the color is not superficial and can not be easily erased.

In a first embodiment, the first material is zirconia.

In a second embodiment, the surface is selectively treated to be converted into carbide.

In a third embodiment, the surface is selectively treated to be transformed into nitride.

In a fourth embodiment, the surface is selectively treated to present a metal deposit in localized areas.

In a fifth embodiment, the surface comprises at least one recess, the surface being treated to be converted into carbide or nitride, and then polished to locate this transformation at said recess.

In a sixth embodiment, the surface comprises at least one projecting portion, the surface being treated to be converted into carbide or nitride, and then polished to exclude this transformation of said projecting portion.

In a seventh embodiment, the surface is converted into carbide or nitride homogeneously, then machined locally to locate the transformation on the non-machined parts.

In an eighth embodiment, the surface is selectively treated to undergo diffusion of a pigment on said surface of the trim element.

The present invention also relates to a portable object comprising the covering element according to one of the preceding claims.

In a first embodiment, said portable object is a timepiece comprising a housing formed by a middle part closed by a bottom and an ice, potentially provided with a bezel and buttons and / or a crown , and a bracelet attached to the middle part via two pairs of horns, and in that the dressing element is chosen to be arranged in the list comprising the middle part, the bezel, the dial, the buttons, the crown, the bottom , the bracelet, the buckle.

The present invention further relates to a method of treating a cladding element for a portable object made of a first material, the first material being a ceramic material having a first color, said method comprising the following steps: Take the trim element and place it in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element; • Heating locally, through a first source of focused heat such as a laser, the surface of the cladding element so that the atoms of the atmosphere of the enclosure combine locally with the surface from the first material to where said surface is heated.

In a first embodiment, the atmosphere is created by dissociating a gas via the same heat source locally heating the surface of the cladding element.

In a second embodiment, the atmosphere is created by dissociation of a gas via a second heat source independent of that which locally heats the surface of the cladding element.

In a third embodiment, the atmosphere is created by dissociation of a gas via a second heat source independent of the first source which locally heats the surface of the covering element, the element of coating being heated homogeneously via a third heat source at a lower temperature than that allowing the combination of the atoms of the atmosphere with the first material, the first heat source for locally raising the temperature of the surface of the cladding element to allow the combination of the atoms of the atmosphere with the first material.

In a first variant, said method comprises the following steps: • Bring the dressing element; • Deposit locally on the surface of said cladding element a metal layer; • Place the covering element in a sealed enclosure containing an atomically charged atmosphere of a chemical element and heat the surface of the cladding element so that the atoms of the enclosure atmosphere are combined with the surface of the first material not covered with the metal deposit.

In a first embodiment, the method further comprises a step of selectively and chemically etching the surface of said dressing element in order to remove the metallic deposit locally, before the carburization or nitriding of the surface of said element. dressing.

In a second embodiment, the selective metal deposition is performed by depositing through a mask previously placed on the cladding element.

In a third embodiment, the step of depositing a selective metal layer consists of depositing a savings layer on the entire surface of said dressing element and then selectively etching this savings layer according to a desired shape and then to deposit the metal layer on the entire surface of said trim element. The remaining savings layer is then removed by etching, leaving the metal layer only where the savings layer has been selectively etched.

In a fourth embodiment, the selective metal deposition is performed by deposition followed by a laser structuring step of the surface of said cladding element.

In a fifth embodiment, the selective metal deposition is performed by deposition followed by a photolithography step of the surface of said cladding element.

In a second variant, said method comprises the following steps: • Bring the dressing element; • Treat said cladding element by placing it in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element and heating its surface so that the atoms of the enclosure atmosphere combine with the surface of the cladding. first material. characterized in that said method further comprises, before or after the step of treating said dressing element, a step of structuring the dressing element allowing the creation of relief on its surface.

In a first embodiment, when the step of structuring the trim element is performed after the step of treating the surface of said trim element, the structuring removes the surface layer on the zones. structured and thus reveals locally the core color of said zirconia cladding element.

In a second embodiment, the method further comprises, when the structuring step of the dressing element is performed prior to the step of treating the surface of said dressing element, a step of polishing to remove the surface layer on the upper part of the raised surface of the covering element and thus reveal locally the core color of said zirconia cladding element.

In a third variant, said method comprises the following steps: • Bring the dressing element; • Deposit a second material on the surface of said trim element; said second material comprising color pigments; • Heat the cladding element to melt or diffuse the pigments into the surface of the cladding element.

In a first embodiment, said step of heating the covering element is carried out in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element so that the atoms of the atmosphere of the enclosure combine with the surface of the first material not covered by the second material.

BRIEF DESCRIPTION OF THE FIGURES

The objects, advantages and features of the invention will appear more clearly in the following detailed description of at least one embodiment of the invention given solely by way of non-limiting example and illustrated by the accompanying drawings in which: :

Figs. 1 and 2 schematically represent the portable object according to the invention;

Figs. 3 to 5 schematically represent a first embodiment of the method according to the invention;

Figs. 6 to 20 schematically represent a second embodiment of the method according to the invention;

Figs. 21 and 22 show schematically a third embodiment of the method according to the invention;

Figs. 23 and 24 show schematically a fourth embodiment of the method according to the invention.

DETAILED DESCRIPTION

In FIGS. 1 and 2, a portable object 1 according to the invention is described. An example of a portable object according to the invention is a timepiece. Such a timepiece comprises a housing 2 formed by a middle part 21 closed by a bottom 22 and an ice 3. This housing 2 encloses an electronic or mechanical or electromechanical watch movement. This portable object may also comprise a bracelet 4 comprising two strands 4 'or a plurality of links. A covering element according to the invention is therefore included in the list comprising the middle part, the bottom, the bracelet, the folding clasp or the buckle - pin necessary for closing the bracelet. Of course, the watch may also include a bezel 23, rotating or not, integrated or not to the middle part, and control means such as a crown head 24 or push buttons 24 '. The middle part 21 may be provided with an integrated or reported bezel.

The dressing element according to the invention is made of a first material. This material is chosen to be of the ceramic type. The ceramic used here is zirconium oxide ZrO 2 also called zirconia.

Advantageously according to the invention, this ceramic trim element 10 is surface-treated. This surface treatment is operated so as to be selective, that is to say that the dressing element is not necessarily treated on its entire surface. This surface treatment is used in order to obtain an improved color diversity or to have a possibility of superior decoration with patterns.

In a first embodiment visible in FIGS. 3 to 5, the treatment according to the present invention consists in a selective carburization / nitriding of the covering element 10 by a focused heat source, such as a laser. As a reminder, a carburation / nitriding is to activate the part to be carburized / nitriding by heating it in an atmosphere charged with carbon atoms or nitrogen.

The first step is therefore to provide the dressing element 10 which will be treated and place it in an enclosure E. This enclosure E is hermetically sealed and contains an atmosphere A charged with carbon atoms C or d nitrogen N according to whether carburetion or nitriding is practiced. This atmosphere charged with carbon atoms C or nitrogen N can be created by dissociation of compounds such as methane CH4, dinitrogen N2 or ammonia NH3. This dissociation is carried out by heating the basic compounds to break the molecular bonds and obtain atomic atmospheres.

The second step is to selectively carburize or nitride the trim member 10 by activating the surface of the piece by heating in selected areas 10 '. In order to be able to selectively heat said surface in the selected areas 10 ', a focused heat source S, e.g. a laser providing a laser beam L, is used. This laser beam is preferentially pulsed. The surface of the covering element 10 is then heated locally in zones 10 'at a temperature of between 700 and 1100 ° C. for a period of 30 to 180 minutes. Under the effect of this temperature, the carbon or nitrogen atoms of the atmosphere A of the enclosure E combine with the zirconia surface in the zones 10 'of the covering element 10. a transformation of the surface of the zones 10 'of the covering element 10 to a small thickness, of the order of 10 to 500 nm, of zirconium carbide or zirconium nitride having a metallic appearance of platinum color or close to yellow gold respectively.

It is therefore a superficial modification of the structure of the zirconia in a new crystallographic structure corresponding to that of zirconium carbide / zirconium nitride and not a reported coating that can be torn off or to separate from the surface the article, in particular when it is subject to conditions of significant wear or shocks. More particularly, the surface layer which has the structure of zirconium carbide or zirconium nitride extends from the surface to a depth of between 10 and 500 nm.

To operate the different steps, it can be provided several modes of execution.

In a first embodiment, the dissociation of the gases to obtain an atmosphere charged with carbon atoms G or nitrogen N and the local activation of the surface of said dressing element 10 use the same laser. .

In a second embodiment, the dissociation of the gases to obtain an atmosphere charged with carbon atoms C or nitrogen N is operated by a first source of heat while the local activation of the surface of the trim element 10 uses the laser.

In a third embodiment, the dissociation of the gases to obtain an atmosphere charged with carbon atoms C or nitrogen N is operated by a first heat source, the dressing element is heated via a second source of heat while the local activation of the surface of the cladding element uses the laser. This third embodiment makes it possible to preheat the cladding element 10 in a homogeneous manner and to have a smaller temperature difference in the area of the surface of the cladding element 10 treated by the focused heat source. .

An advantage of this first embodiment is that it allows easy selective activation of the surface of the covering element 10. Indeed, a laser beam has the advantage of having an adjustable beam diameter .

In a second embodiment visible in FIGS. 6 to 20, the principle used is a selective metallization.

The first step is therefore to provide the cladding element 10 and affix a metallization 11 on its surface. This metallization 11 is selective, that is to say that it is performed on the area or zones that it is desired not to fuel or nitride. This metal deposit is made for example in a material included in the list including chromium, tantalum, molybdenum, tungsten, niobium, titanium, silicon, boron and is made according to several embodiments.

In a first embodiment shown in FIGS. 7 and 8, the metallization is carried out by masking the surface of the covering element 10 via a mask 12 followed by a metal deposition via a PVD physical vapor deposition method. Thus, only zones Z not covered by the mask receive the metal deposit 11.

In a second embodiment shown in FIGS. 9 to 12, the metallization is carried out by depositing a savings layer 13 such as a capton layer or a layer of ink or lacquer or resin on the surface of the covering element. This layer 13 is then selectively etched according to the desired aesthetic and reveals openings 13 '. The whole is then covered with a metal layer 11 by PVD deposition, the layer being deposited on both the savings layer 13 and in the recesses 13 'made in said savings. Finally, the savings layer 13 is removed by etching, leaving the metal layer 11 only on the zones Z corresponding to the locations of the recesses 13 'of the savings removed.

In a third embodiment shown in FIGS. 13 to 15, the selective metal deposition consists of depositing the metal 11 over the entire surface of the covering element 10 and then using a focused heat source S such a laser to structure the deposited metal layer 11. This structuring consists of stripping the surface of the covering element 10 to remove the metal layer 11 at undesired locations and leaving the metal layer 11 on the desired zones Z.

In a fourth embodiment shown in FIGS. 16 to 18, the selective metal deposition consists of depositing the metal on the entire surface of the covering element 10. Following this, a photolithography step with a mask 12 is used to locally modify the deposited metal layer. This local modification is followed by a chemical attack step to remove the metal layer 11 at unwanted locations and leave it on the desired zones Z.

Once this metal deposition achieved, the next step is to carburize or nitride the trim element 10 with the metal layer 11 on the Z zones of its surface. For this purpose, the covering element 10 is placed in an enclosure E which contains an atmosphere A loaded with carbon atoms C or nitrogen N, as shown in FIG. 19. The whole is then heated using a plasma technique as described in patent EP 0 850 900. However, the metal deposit 11 serves here shield preventing carburation / nitriding areas covered by this metal layer 11 and allowing the transformation to the zones 10 'uncovered as visible in FIG. 20.

In the case where the cladding element 10 is made of white zirconia, the reduction made during said carburization / nitriding results in the appearance of a gray color of the zirconia under the PVD layer. In the case of a black zirconia, the covering element 10 retains its black color allowing an additional step in which the metal deposit 11 is chemically dissolved to reveal the zirconia in its black color. A contrast is thus obtained between the black zirconia and the remainder of the carburized or nitrided trim element.

In a third embodiment visible in FIGS. 21 and 22, the selective coloration of the dressing element 10 uses the principle of carburation / nitriding and structuring.

In a first embodiment shown in FIG. 21, the first step is to provide the cladding element 10 zirconia. Preferably, the zirconia used is black zirconia. This first step also consists in structuring this element of dressing. This structuring can be operated in two different ways: During the manufacture of the trim element or after this manufacture. These structures 17 are in the form of recesses 17b or protrusions 17a.

In the case where the structuring is carried out during the manufacture of the covering element 10, it will be understood that this manufacture consists of mixing together the powders to then put them in a mold and sinter them, that is to say subject them to a temperature and a pressure such that a transformation takes place. Thus, the mold in which the powders are placed can have a shape including the desired structures.

In the case where the structuring is carried out after the manufacture of the cladding element 10, a mechanical or laser machining is possible.

In a second step, the trim element is carburized or nitrided. For this, the structured dressing element 10 is placed in an enclosure E in which there is an atmosphere A charged with carbon atoms or nitrogen. The whole is then heated via a plasma for a predetermined period of time in order to transform the surface of the cladding element into carbide or nitride of zirconium respectively. This carburation / nitriding is therefore performed on the entire surface of the covering element 10.

In a third step, the covering element 10 undergoes a polishing step. This polishing step consists in removing the surface layer of the covering element. However, the cladding element is provided with structures 17 in the form of recesses 17b or protrusions 17a, these recesses 17b or protrusions 17a being also carburized / nitrided. Therefore, the polishing does not affect the entire surface of the covering element 10. Indeed, in the case where the structures 17 are recesses 17b, the polishing operation leaves the carburation / nitriding in the recesses . In the case where the structures 17 are protrusions 17a, the polishing operation removes the carburization / nitriding at these protrusions 17a.

Thus, a contrast is obtained between the polished portion of the cladding element 10 and the carburized / nitrided portion.

In a second embodiment shown in FIG. 22, the first step is to provide the cladding element 10 zirconia.

In a second step, said dressing element is carburized / nitrided. For this, the structured dressing element 10 is placed in an enclosure E in which there is an atmosphere A charged with carbon atoms or nitrogen. The whole is then heated via a plasma for a predetermined period of time in order to transform the surface of the cladding element into carbide or nitride of zirconium respectively. This carburation / nitriding is therefore performed on the entire surface of the covering element 10.

In a third step, the covering element 10 undergoes a structuring step. This step involves removing material from the trim element. For this, a mechanical or laser machining is used. The removal of material can be carried out so as to remove locally only the surface layer of 10 to 500 nm which is converted into carbide or nitride zirconium. However, the removal of material can be operated so as to create a visible hollow in order to associate the contrast to a relief, this relief can accentuate said contrast.

In a fourth embodiment visible in FIGS. 23 and 24, the selective coloration of the covering element 10 uses pigments, for example enamels or inks. This embodiment consists in a first step in providing the covering element 10.

In a second step, it is necessary to provide inks or colored enamels 16. These enamels are in the form of an oil comprising a powder of colored pigments.

These inks or enamels 16 are then arranged on the surface of the covering element 10 according to the desired pattern. For this, a printing machine is used.

In a third step, the covering element 10 provided with the selective deposition of inks or enamels 16 undergoes a diffusion step. This diffusion step consists of heating the covering element to fix the color.

According to a first embodiment, the diffusion step consists of annealing to fix the color. This annealing consists of passing the dressing element in an oven. For enamels, the temperature of the oven reaches 800 ° C. At this temperature, the oil in which the pigments are suspended evaporates while the pigments are melted on the surface or diffuse into the surface of the dressing element.

In a second embodiment, the diffusion step consists of a carburation / nitriding. This step then consists in placing the covering element 10 provided with the selective deposition of inks or enamels 16 in a hermetically sealed enclosure E containing an atmosphere A loaded with carbon atoms C or nitrogen N, depending on whether the 'we

Claims (23)

practice carburetion or nitriding respectively. The surface of the workpiece is activated by plasma heating at a temperature between 700 and 1100 ° C for a fixed period. Under the effect of this temperature the carbon atoms or nitrogen of the atmosphere A of the enclosure E combine with the zirconia surface of the dressing element 1. A covering element (10) for a portable object (1) made of a first material, the first material being a ceramic material having a first color, characterized in that at least one surface of said covering element is at least one partially treated so as to have at least one transformation (10 ') provided with a coloring different from the first color. 2. Cladding element according to claim 2, characterized in that the first material is zirconia. 3. cladding element according to claims 1 or 2, characterized in that the surface is selectively treated to be converted into carbide. 4. Cladding element according to claims 1 or 2, characterized in that the surface is selectively treated to be converted into nitride. 5. cladding element according to one of the preceding claims, characterized in that the surface is selectively treated to have a metal deposit (11). 6. cladding element according to one of claims 1 to 4, characterized in that the surface comprises at least one recess (17b), the surface being treated to be converted into carbide or nitride, and polished to locate this transformation to level of said hollow. 7. cladding element according to one of claims 1 to 4, characterized in that the surface comprises at least one projecting portion (17a), the surface being treated to be converted into carbide or nitride and polished to exclude this transformation of said projecting portion. 8. cladding element according to one of claims 1 to 4, characterized in that the surface is selectively treated to undergo the deposition or diffusion of pigments (16) on said surface of the cladding element. 9. Portable object comprising the covering element (10) according to one of the preceding claims. 10. Portable object according to claim 9, characterized in that said portable object is a timepiece comprising a housing (2) formed by a middle part (21), provided with a bezel, closed by a bottom (22) and an ice cream (3), said portable object further comprising control means (24, 24 '), a dial and a bracelet (4) with a clasp and attached to the middle via two pairs of horns, and in that the element dressing is chosen to be arranged in the list comprising the middle part, the bezel, the dial, the control means, the bottom, the bracelet and the clasp. 10. It is a transformation of the cladding element to a small thickness, of the order of 10 to 500 nm, zirconia (zirconium oxide) in the outer region of the cladding element being transformed into zirconium carbide or zirconium nitride having a metallic appearance of platinum color or close to yellow gold respectively. At the same time, the heat of the oven also makes it possible to heat the inks or enamels 16 so as to melt them on the surface or make them diffuse into the surface of the covering element 10. We are therefore left with a covering element 10 whose surface is carburized or nitrided in the zones 10 'and colored on the areas on which the inks or enamels 16 were deposited as visible in FIG. 24. This technique advantageously allows to have a contrast between the carburized / nitrided portion and the colored portion. It will be understood that various modifications and / or improvements and / or combinations obvious to those skilled in the art can be made to the various embodiments of the invention described above without departing from the scope of the invention defined by the appended claims. Thus, it will be understood that the covering element can be treated at different locations on its surface. claims 11. A method of treating a portable object covering element (10) made of a first material, the first material being a ceramic material having a first color, said method comprising the following steps: • Providing the element dressing and place it in an enclosure (E) hermetically closed and containing an atomically charged atmosphere of a chemical element; • Heating locally, via a first focused heat source (S), the surface of the cladding element so that the atoms of the chamber's atmosphere combine with the surface of the first material . 12. The treatment method according to claim 11, characterized in that the atmosphere is created by dissociating a gas via a second heat source. 13. The treatment method according to claim 11, characterized in that the atmosphere is created by dissociation of a gas via a second heat source, the dressing element being heated to a temperature lower than the temperature of activation of the combination of the atoms of the atmosphere with the surface of the first material via a third source of heat. 14. A process for treating a portable object covering element (10) made of a first material, the first material being a ceramic material having a first color, said method comprising the following steps: • Providing the element dressing; • Deposit locally on the surface of said cladding element a metal layer (11); • Place said cladding element in a hermetically sealed enclosure (E) containing an atomically charged atmosphere of a chemical element and heat the surface of the cladding element so that the atoms of the enclosure atmosphere combine with the surface of the first material not covered with the metal deposit. 15. Processing method according to claim 14, characterized in that it further comprises a step of selectively and chemically attacking the surface of said dressing element in order to remove the metal deposit. 16. The treatment method according to claims 14 or 15, characterized in that the selective metal deposition is performed by depositing through a mask (12) previously placed on the cladding element. 17. Processing method according to claim 14 or 15, characterized in that the step of depositing a metal layer consists of depositing a savings layer (13) on the entire surface of said dressing element and then etching selectively this savings layer in a desired shape and then to deposit the metal layer (11) on the entire surface of said dressing element, the remaining savings layer being subsequently removed by etching, thus leaving the metal layer to places where the savings layer was previously engraved. 18. Processing method according to claim 14 or 15, characterized in that the selective metal deposition is performed by deposition followed by a laser structuring step of the surface of said cladding element. 19. Processing method according to claim 14 or 15, characterized in that the selective metal deposition is carried out by deposition followed by a photolithography step of the surface of said cladding element. 20. A method of treating a portable object covering element (10) made of a first material, the first material being a ceramic material having a first color, said method comprising the following steps: • Providing the element dressing; • Treat said cladding element by placing it in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element and heating its surface so that the atoms of the enclosure atmosphere combine with the surface in question. first material. characterized in that said method further comprises, prior to or subsequent to the step of treating said dressing member, a step of structuring the trim member to create a relief (17) on its surface and of reveal the color of the first material in contrast with the color of the carburised or nitrided surface. 21. Treatment method according to claim 20, characterized in that it further comprises, when the step of structuring the dressing element is performed prior to the step of treating said dressing element, a polishing step for removing the carburised / nitrided surface layer on the protruding portions of the raised surface of the trim member. 22. A process for treating a portable object covering element (10) made of a first material, the first material being a ceramic material having a first color, said method comprising the following steps: • Providing the element dressing; • Depositing a second material (16) on the surface of said dressing element; said second material comprising color pigments; • Heat the trim element to melt or diffuse the pigments into the surface of the trim element (10). 23. The treatment method as claimed in claim 22, characterized in that said step of heating the dressing element is carried out in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element so that the atoms the atmosphere of the enclosure combine with the surface of the first material not covered by the second material.