阅读说明：本技术 陶瓷组件的制造 (Manufacture of ceramic components ) 是由 西里亚克·博卡尔 奥利维耶·皮若尔 于 2018-04-16 设计创作，主要内容包括：一种用于制造钟表或珠宝首饰的陶瓷部件的方法,所述陶瓷部件尤其含有氧化锆和/或氧化铝,其特征在于,该方法包括通过原子层沉积(ALD)将至少一种添加的元素或化合物沉积在陶瓷粉末,可选地粘结的陶瓷粉末上的步骤(E3)。(A method for manufacturing ceramic parts for watches or pieces of jewellery, in particular containing zirconia and/or alumina, characterized in that it comprises the step of depositing at least one added element or compound on a ceramic powder, optionally a bonded ceramic powder, by Atomic Layer Deposition (ALD) (E3).)

1. method for manufacturing a ceramic powder with or without a binder, comprising at least one added element or compound, in particular based on zirconia and/or alumina and/or strontium aluminate, wherein the method comprises a step (E3) of depositing at least one added element or compound on the ceramic powder by Atomic Layer Deposition (ALD).

2. Method for manufacturing a ceramic powder with or without binder according to the preceding claim, wherein the deposition step (E3) comprises the addition of less than or equal to 3 wt.%, or less than or equal to 1 wt.%, or less than or equal to 0.05 wt.%, or less than or equal to 0.01 wt.% of said at least one added element or compound, excluding organic compounds, with respect to the total amount of ceramic powder which does not comprise possible organic compounds.

3. The method for manufacturing a ceramic powder with or without a binder according to any of the preceding claims, wherein the deposition step (E3) comprises adding a total amount of greater than or equal to 1ppm, or greater than or equal to 10ppm of the at least one added element or compound, the at least one added element or compound not comprising an organic compound.

4. Method for manufacturing a ceramic powder with or without a binder according to any of the preceding claims, wherein the deposition step (E3) comprises depositing an additional compound selected from metals, and/or metal alloys, and/or oxides, and/or nitrides, and/or carbides.

5. Method for manufacturing a ceramic powder with or without a binder according to the preceding claim, wherein the added element or compound is or comprises at least one metal selected from at least one of the following four lists:

-a high melting noble metal selected from platinum, rhodium, osmium, palladium, ruthenium or iridium; or

-any other metal selected from gold, aluminum, silver, rhenium, titanium, tantalum or niobium; or

-a transition metal selected from aluminium, iron, chromium, vanadium, manganese, cobalt, nickel or copper;

-a lanthanide selected from lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium.

6. Method for manufacturing a ceramic powder with or without binder according to any of the previous claims, wherein the added compound is a metal alloy obtained by direct deposition of a metal alloy on a ceramic powder with or without binder or by a combination of sequential or simultaneous deposition of several elements of a metal alloy or compound on a ceramic powder with or without binder.

7. Method for manufacturing a ceramic powder with or without a binder according to any of claims 1 to 6, wherein the added element or compound is an oxide, carbide or nitride of one or more metals obtained by direct deposition of the metal oxide, carbide or nitride on the ceramic powder with or without a binder or by reacting the metal deposit with a reactive atmosphere, in particular in a deposition chamber or after deposition, for example during the step of sintering the ceramic compound.

8. Method for manufacturing a ceramic powder with or without a binder according to any of the preceding claims, wherein the deposition step (E3) comprises the simultaneous or sequential deposition of a plurality of different added elements or compounds.

9. The method of ceramic powder with or without binder according to any of the preceding claims, wherein the depositing step (E3) comprises adding at least one added element or compound to the ceramic powder with binder comprising 1 to 4 wt. -%, 12 to 25 wt. -%, or 1 to 25 wt. -% of an organic compound or to the ceramic powder not comprising an organic compound.

10. The method for manufacturing a ceramic powder with or without a binder according to any of the preceding claims, wherein the method comprises:

-a first stage (P1) consisting in preparing ceramic powders, in particular based on zirconia and/or alumina and/or strontium aluminate, and then in

-a deposition step (E3) comprising depositing at least one additional element or compound on the ceramic powder by Atomic Layer Deposition (ALD), followed by

-a second stage (P2) consisting in integrating a binder of the organic material type into the ceramic powder comprising said at least one added element or compound; then, the user can use the device to perform the operation,

-optionally, a further deposition step (E4) comprising depositing on the ceramic powder by Physical Vapor Deposition (PVD) and/or by Chemical Vapor Deposition (CVD) and/or by Atomic Layer Deposition (ALD) at least one further added element or compound, which is the same or different from the at least one added element or compound;

Or, wherein the method comprises:

-a first stage (P1) consisting in preparing ceramic powders, in particular based on zirconia and/or alumina and/or strontium aluminate, and then in

-a second stage (P2) consisting in integrating a binder of the organic material type into the ceramic powder so as to form a ceramic powder with a binder; then the

-a deposition step (E3) comprising depositing at least one added element or compound on the ceramic powder with binder by Atomic Layer Deposition (ALD); then the

-optionally, a further deposition step (E4) comprising depositing on the ceramic powder by Physical Vapor Deposition (PVD) and/or by Chemical Vapor Deposition (CVD) and/or by Atomic Layer Deposition (ALD) at least one further added element or compound, which is the same or different from the at least one added element or compound.

11. A method for manufacturing a ceramic component, wherein the method comprises a stage for manufacturing a ceramic powder according to any of the preceding claims, with or without a binder.

12. Method for manufacturing a ceramic component according to the preceding claim, wherein, after the deposition step (E3) comprising the deposition of at least one additional element or compound, the manufacturing method proceeds:

-a third stage (P3) of temporarily shaping the ceramic powder with binder comprising said at least one added compound, and then

-a fourth phase (P4) comprising the step of degreasing the temporarily shaped ceramic component, in particular comprising the elimination of organic compounds, and then sintering said ceramic component.

13. the method for manufacturing a ceramic component according to claim 11 or 12, wherein, before or after the step (E3) of depositing at least one added compound, the method comprises a step of adding a coloring pigment or a phosphorescent pigment, in particular a coloring compound other than the initially added coloring pigment, to the ceramic powder with or without a binder.

14. The method for manufacturing a ceramic component according to any of claims 11 to 13, wherein the method comprises the steps of:

-providing a ceramic powder with a binder comprising a colour pigment or more typically at least one added and/or further compound, whereby a ceramic component having a first colour or more typically a first property can be obtained by manufacturing a ceramic component from such a ceramic powder with a binder;

-depositing at least one added element or compound on the ceramic powder with binder by Physical Vapour Deposition (PVD) and/or by Chemical Vapour Deposition (CVD) and/or by Atomic Layer Deposition (ALD) (E3; E4);

-completing the manufacturing of the ceramic component from the ceramic powder with binder comprising the deposited added elements or compounds to obtain the ceramic component, the color of which is a second color different from said first color, or more generally the ceramic component has a second property different from the first property.

15. Method for manufacturing a ceramic component according to the preceding claim, wherein the method comprises: the step of depositing at least one additional element or compound on the ceramic powder with said binder is repeated with a plurality of different deposits of at least one additional compound by varying the content and/or said additional compound until the ceramic component has a second color or second property sufficiently close to the desired one after the manufacture of the ceramic component is completed.

16. the method for manufacturing a ceramic component according to claim 14 or 15, wherein the method comprises the steps of: a ceramic powder with a binder is selected that contains at least one compound that is capable of achieving a first property that is close to a desired second property.

17. The method for manufacturing a ceramic component according to any one of claims 14 to 16, wherein said method is capable of manufacturing a bezel, a dial, an indicator, a winding crown, a push button or any other timepiece case element or any timepiece movement element.

18. Ceramic powder with a binder, in particular obtained by a method according to any one of claims 1 to 10, wherein the ceramic powder with a binder comprises, in total, less than or equal to 3 wt.%, or less than or equal to 1 wt.%, or less than or equal to 0.05 wt.%, less than or equal to 0.01 wt.% of added elements or compounds selected from metals, and/or metal alloys, and/or oxides, and/or nitrides, and/or carbides, the amounts being measured in the absence of organic compounds.

19. Ceramic component for a timepiece or jewelry part, in particular based on alumina and/or zirconia and/or strontium aluminate, wherein it comprises a total amount of compounds added selected from metals, and/or metal alloys, and/or oxides, and/or nitrides, and/or carbides of less than or equal to 3% by weight, or less than or equal to 1% by weight, or less than or equal to 0.05% by weight, less than or equal to 0.01% by weight, said ceramic component not comprising organic compounds.

20. A timepiece or jewelry part comprising a ceramic assembly according to the preceding claim.

Technical Field

The present invention relates to a method for manufacturing ceramic powder and a ceramic component. Such ceramic powders and ceramic components are used in watchmaking and jewelry industries. In particular, such a component can be used in a timepiece, in particular a decorative component such as a bezel or a functional component such as a movement.

background

In the field of watchmaking, as in jewelry, it is known to use ceramic components, in particular decorative components. However, one limiting factor in the use of these ceramic components is due to the fact that: it is difficult or even impossible to obtain certain colors, in particular certain grey shades, and it is difficult to obtain uniform, predictable and reproducible colors. Furthermore, obtaining a particular shade requires the production of a whole batch of material from the initial assembly and proves to be time consuming and complex.

Another limiting factor also comes from the fact that: it is difficult to test the effect of adding certain elements that can be used in combination with the composition of known ceramics, in particular in order to obtain certain specific mechanical properties of the ceramic component. Here too, each test is complicated and requires the production of a whole batch of material from the starting components.

Conventional processes for manufacturing ceramic components comprise a first stage consisting in preparing raw materials, i.e. ceramic powders, for example based on zirconia and/or alumina. In this first stage, the raw material is generally prepared in the form of a ceramic powder, to which, for example, other oxides may be added to reinforce the ceramic composition, or pigments to obtain a coloured material. The pigments are generally of the metal oxide type or rare earth oxide type and are added to and mixed with the base ceramic powder by a liquid route, thus using a carrier liquid to introduce the pigments.

The second stage of the method for manufacturing a ceramic component consists in incorporating a binder into the ceramic powder obtained in the first stage. Such binders are typically composed of one or more organic compounds. The nature and proportions of the binder depend on the intended method in the third stage and at the end of this stage usually ceramic powders with binder are involved.

The third stage includes the shaping of the ceramic assembly. To this end, the first route comprises a step of pressing the agglomerates of particles together with the binder obtained at the end of the second stage: in this method, a second stage prepares the ceramic powder with the binder in the form of spray-dried compacted granules. The second route consists of injection molding. In this case, the formulation resulting from the second stage is a ceramic powder with a binder, which is referred to as "feed". The third route consists of casting in a mould (commonly known as slip casting). In this case, the formulation resulting from the second stage is a ceramic powder with suspended binder, also known as slip or "slurry". At the end of the third stage, the ceramic component has a shape close to its final shape and contains ceramic powder and a binder. Other molding techniques such as gel casting, freeze casting or coagulation casting techniques may be used.

The fourth stage may grind the ceramic assembly. This fourth stage comprises a first step consisting in degreasing the assembly, i.e. removing the binder, for example by heat treatment or using a solvent. The second step is to compact the assembly, thereby removing the holes created by the removal of the adhesive. The second step usually consists of a sintering heat treatment (high temperature firing). The final colour of the ceramic component and its final mechanical properties appear only at the end of the fourth phase and result from the reactions between the various constituents of the component and the atmosphere present in the furnace (which plays a role during the heat treatment). These reactions are complex and sometimes unpredictable.

It is observed that the above mentioned conventional methods for manufacturing ceramic components have several drawbacks. In particular, the colour and final properties obtained depend on many parameters, such as the microstructure of the powder formed in the first stage, in particular the size of the ceramic grains, the size of the pigments, their reactivity with the ceramic and sintering environment, etc. The properties also depend on all other factors related to the other manufacturing stages, such as the size and number of pores in the final assembly, the composition of the grain boundaries, the density, the percentage of pigments and their distribution within the matrix, their possible bonding to each other during sintering or to the constituents of the ceramic raw material or atmosphere, the chemical purity of the initial compounds, and possible internal and external contaminants. The parameters to be considered are so numerous that it is difficult to predict and reproduce a certain color that is desired to be manufactured. This observation is more true if the content of the coloring pigment is small: therefore, to alleviate this disadvantage, all of the prior art methods must use large amounts of pigment. Furthermore, some methods attempt to improve the results by adding steps based on complex chemistry, which naturally has the disadvantage of further complicating the manufacturing process.

More importantly, in practice, the difficulty in managing the color of the ceramic components results in the need to perform a large number of tests, including from ceramic powder preparation to final molding to generate a large number of complete samples, while varying some of the above parameters for each sample to determine the best method. Furthermore, when it is desired to change the color even slightly, it is necessary to restart the entire process, including preparing numerous samples again. In practice, therefore, finding a controllable ceramic component color, which is often necessary for its use as a decorative element, requires complex and laborious development steps.

Finally, despite numerous tests, it has so far been observed that it does not seem possible to obtain ceramic components having certain colours, in particular certain grays, such as those defined by CIE L a b colour coordinates (83; 0; 0.6) and CIE L a b colour coordinates (47; 0.2; -0.2). In general, it is not possible to obtain colors, defined for example by a and b parameters close to 0 and L parameters less than 96, in particular strictly grey.

The general object of the present invention is therefore to propose a solution for manufacturing ceramic components, in particular for a timepiece, which does not have the drawbacks of the prior art.

More precisely, a first object of the present invention is to propose a solution for manufacturing ceramic powders and ceramic components, making it possible to obtain ceramics with improved properties, in particular with controllable colours and/or in particular with novel or optimised properties (such as mechanical, thermal, electrical and tribological properties).

a second object of the invention is to propose a solution for simplifying the manufacture of coloured ceramic components.

A third object of the invention is to propose a grey ceramic.

A fourth object of the invention is to propose a simple method of modifying a ceramic powder which may already be coloured in order to modify the resulting colour of the finished ceramic component.

Disclosure of Invention

to this end, the invention is based on a method for producing a ceramic powder or ceramic component with or without a binder, in particular a ceramic powder or ceramic component with or without a binder for a timepiece or jewelry part, in particular a ceramic powder or ceramic component with or without a binder based on zirconium oxide and/or aluminum oxide and/or strontium aluminate, wherein the method comprises the step of depositing at least one added element or compound on the ceramic powder with or without a binder by Atomic Layer Deposition (ALD), possibly followed by further Atomic Layer Deposition (ALD), and/or by Chemical Vapor Deposition (CVD) and/or by Physical Vapor Deposition (PVD).

The invention is more particularly defined by the claims.

drawings

These objects, features and advantages of the present invention will be disclosed in detail in the following non-limiting description of specific embodiments with reference to the accompanying drawings, in which:

Fig. 1 schematically shows a flow chart of the steps of a method for manufacturing a coloured ceramic component for a timepiece according to an embodiment of the invention.

Fig. 2 shows the microstructure of a ceramic component obtained according to a first example of embodiment of the invention.

Fig. 3 shows the microstructure of a ceramic component obtained according to a second example of embodiment of the invention.

Fig. 4 is a table of results for ceramic components obtained in accordance with two previous example implementations of embodiments of the present invention.

Detailed Description

In the following, ceramic component or powder denotes a component or powder obtained from a polycrystalline compact material comprising mainly at least one ceramic, in particular based on zirconia and/or alumina and/or strontium aluminate, for example zirconia stabilized with yttria and/or ceria and/or magnesia and/or calcia. Ceramic powder means a powder in the form of a finely divided solid consisting of fine particles of a ceramic, in particular a ceramic based on zirconia and/or alumina and/or strontium aluminate. For the sake of simplicity of description, the same term "ceramic powder" will be used with the intention of reserving in a general manner for powders that contain predominantly fine particles of the ceramic but also other additive elements such as one or more pigments or oxides for reinforcing the ceramic, such as yttrium oxide. Similarly, a ceramic component means a component obtained by, for example, sintering such a ceramic powder. Thus, in all cases, the ceramic powder or component mainly comprises a component of ceramic type, i.e. at least 50 wt.%, or even at least 75 wt.%, or even at least 90 wt.%. For example, the ceramic powder or component comprises at least 50 wt% zirconia.

in all cases, the ceramic powder is free of organic compounds. The generic term "ceramic powder with binder" denotes a composite material consisting of a ceramic powder and a binder, usually consisting of one or more organic compounds in variable proportions, and used for shaping parts by pressing, by injection molding, by casting or by other techniques.

by (pressed) particles is meant agglomerates of ceramic powder with a binder to be formed by a pressing method, such as cold or hot uniaxial pressing or cold or hot isostatic pressing. The particles typically comprise 1 to 4% by weight of the organic compound.

The term "injectable ceramic powder", also commonly referred to as "charge", will denote a ceramic powder with a binder to be shaped by a high or low pressure injection molding process. Injectable ceramic powders typically comprise 12 to 25% by weight of organic compounds.

The term "slurry" means a ceramic powder with a binder to be formed by slip casting or gel casting. The slurry typically comprises 1 to 25 wt% of organic compounds.

A method for manufacturing a ceramic component according to an embodiment of the invention comprises the stages and steps schematically represented by the flow chart of fig. 1.

Thus, the manufacturing method comprises the respective conventional stages P1 to P4, i.e. preparing the ceramic powder (P1), adding the binder (P2), shaping the assembly (P3) and degreasing sintering heat treatment (P4). Since the conventional parts of these stages are known in the art, they will not be described in detail at this stage. Therefore, those skilled in the art will know how to implement them, including according to any existing variants or equivalents.

embodiments of the present invention differ from conventional methods, inter alia, in the addition of step E3, i.e. the deposition of at least one added element or compound, such as a coloring element, via a dry route by atomic layer deposition abbreviated ALD.

Thus, after the first stage P1 or the second stage P2 of the manufacturing method, the deposition step E3 is carried out on ceramic powders with or without binders. Thus, it can be carried out on ceramic powders comprising only ceramic particles or on ceramic powders comprising organic compounds, for example on granules or on injection molding feeds. It is carried out before the third stage P3 of the process. For the sake of simplicity of description, the ceramic powder comprising one or more added elements or compounds obtained by carrying out the deposition step E3 of the present invention will continue to be referred to as ceramic powder with or without binder.

The elements or compounds added, in particular metals and/or oxides and/or nitrides and/or carbides, can vary greatly. Metal is understood to mean a pure metal or alloy. Thus, it may advantageously be a metal-based compound. For simplicity, the terms added element or added compound will be used in the remainder of the text without distinction between individual elements and compounds or alloys.

The invention also makes it possible, in a novel way, to use metals that cannot be used with existing solutions, such as noble metals with a high melting point higher than or equal to 1200 ℃, or even higher than or equal to 1500 ℃. The invention thus makes it possible to use platinum and/or rhodium and/or osmium and/or palladium and/or ruthenium and/or iridium as additional element. As a variant, other metals may be used, and the aforementioned list may be supplemented with gold, aluminum, silver, rhenium, titanium, tantalum or niobium. Furthermore, according to the following list, transition metals (iron, chromium, vanadium, manganese, cobalt, nickel and copper) characterized by an incomplete d-shell are able to obtain particularly unprecedented advantageous results due to their addition according to the specific deposition step E3 of the present invention. Likewise, the lanthanides (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) enable doping of the ceramic powder with or without binder during step E3 and enable advantageous colours and/or properties to be obtained. As mentioned above, the added compound may thus be an alloy comprising or consisting of one or more of the metals listed above and the lanthanide.

thus, the added compound may be a metal compound or alloy obtained by depositing a metal alloy directly on a ceramic powder with or without a binder or by a combination of depositing a plurality of elements of a metal alloy sequentially or simultaneously on a ceramic powder with or without a binder.

similarly, the compound added may be an oxide, carbide or nitride of one or more metals obtained by direct deposition of the oxide, carbide or nitride on a ceramic powder with or without a binder or by reacting the metal deposit with a reactive atmosphere, in particular in a deposition chamber or after deposition, for example during the step of sintering the ceramic compound.

Naturally, a plurality of different added elements or compounds can be used and deposited simultaneously or successively on the same ceramic powder by one or more deposition steps E3 as described above. This increase in available additional compounds naturally enables an increase in the possible colour of the ceramic and in other possible properties, in particular mechanical or tribological properties.

It should be noted that the person skilled in the art is used to add colour pigments to ceramics by liquid route. They are not used to proceed by the dry route or to deposit directly on ceramic powders with or without binders. During this dry deposition under vacuum, the following parameters should be considered:

-the uniformity of the deposition on the powder,

uniformity of shape and size of the particles of the powder,

-the temperature of the process,

The risk of degassing,

electrostatic properties of the (insulated) moving fragmented solids,

-the finish and properties of the device material; in particular, the pairing between the nature of the deposit and the nature of the binder of the granules must be chosen correctly to prevent the powder from adhering to the equipment.

It was observed that the method of the invention enables very satisfactory results to be achieved in terms of novel or improved properties of the ceramic component, even with the addition of very small amounts of added compounds to the ceramic. Thus, not only is the color of the ceramic component improved as it is homogeneous and/or may allow new hues, but the result of such an improvement may be obtained by adding very small amounts of further coloring elements or compounds, especially in amounts much lower than the content of coloring pigments used in conventional processes, compared to existing solutions.

For example, the ALD deposition process is used to obtain a weight content of further elements or compounds, possibly lower than or equal to 3%, but in particular lower than or equal to 3% or 2%, or even lower than or equal to 1%, or even lower than or equal to 0.05%, or even lower than or equal to 0.01%. It should be noted that all weight contents are measured on the final (after performing the fourth stage of the manufacturing method) ceramic component or on the degreased ceramic powder, i.e. without taking into account the weight of the binder. Advantageously, these contents are greater than or equal to 1 ppm. Advantageously, these levels are from 1ppm to 0.01%, or even from 1ppm to 0.05%, or even from 1ppm to 3%. Therefore, the invention has the following advantages: very advantageous results are obtained with small amounts of added compound material or even very small amounts of material, without having to prepare a complete batch each time, and in addition the base batch can be iteratively modified.

furthermore, it is important to emphasize that the process of the invention enables to obtain a homogeneous distribution or a good dispersion of the added compounds and thus finally to obtain ceramic components with homogeneous properties (e.g. colour). If the deposition of the added element is carried out on a ceramic powder, the ceramic powder thus enriched is subjected to a successive dispersion/wet-milling step to combine it with an organic compound and then to spray-dry it, before being subjected to the second stage of the process, from which granules are prepared at the end of the second stage P2 of the process. This second stage P2 thus enables a homogeneous distribution of the added compound. As a variant, since the added compound is deposited after the second phase P2 of the method, for example directly on the granules, the added compound is distributed on the surface of the granules by the deposition method used and is therefore uniformly distributed on the ceramic powder with the binder. The added compound will be evenly distributed in the final sintered ceramic component.

The uniformity of ALD deposition enables the distribution of the coating over the powder and, in the case of metallic coatings, the powder becomes less electrostatic. It aggregates less.

In both of the preceding cases, the analysis of the object obtained at the end of the fourth phase (P4) showed that a uniform distribution of the added compound remained in the final ceramic assembly. If the deposition has been carried out on a ceramic powder, a final distribution of the added compound particles in the ceramic microstructure occurs, which is random and microscopically homogeneous. In the case of deposition onto the injection molding material, in particular in the step of plasticizing the molten mixture by means of the injection molding screw, the distribution of the particles of the added compound in the material is homogenized. Thus, in all cases, the ceramic component comprises an added element that is uniformly distributed in its volume, which gives it the properties provided by the uniform distribution of the added element in the ceramic component.

Finally, the deposition step E3 of the embodiment of the invention has the following main advantages:

The addition of added elements or compounds can be obtained in a fully controllable composition and content and in very small amounts, so that a micro-metering of the added compounds or elements can be achieved.

It is possible to finally obtain a homogeneous distribution of the added compound in the ceramic component;

The possibility of adding a plurality of other compounds, increasing the number of possible other compounds compared to existing solutions, increasing the possibility of providing ceramic components with certain properties;

It enables reliable, repeatable and clean deposition of other compounds.

The present invention is exemplified below by examples which enable the production of gray ceramic components having a hue which cannot be produced by conventional techniques. All the results obtained, in particular in terms of colour, are summarized in the table of figure 4.

the first example uses a ceramic powder based on yttria-stabilized zirconia (TZ3YS) without a binder, consisting of 3 mol%. 10g of this powder was placed in the vibrating bowl of the ALD chamber and evacuated to initiate the deposition of platinum by the ALD process. 50 deposition cycles were performed.

the ceramic powder thus coated is then subjected to grinding (mixing, wet grinding) and binding processes. In this treatment, 0.6g of PVA, 0.9g of PEG 20000 and 116ml of deionized water were added to 50.4g of the platinum coated ceramic powder. The suspension thus obtained was placed in the zirconia bowl of a mill with 1kg of zirconia beads and milled/milled at a speed of 400rpm for 2 hours. The suspension is then recovered for drying and granulation by spray drying using a "spray dryer". The granules thus obtained are then pressed into a cylindrical mould on a uniaxial press. The resulting pellets were degreased in air at 600 ℃ for 18 hours. Finally, it was sintered in air at 1450 ℃ for 2 hours. After sintering, the surface of the ceramic pellet is ground and then polished. The ceramic component obtained is grey in colour. Fig. 2 is an image of the sintered ceramic pellet obtained by a Scanning Electron Microscope (SEM), which shows the distribution of platinum particles (bright spots). The figure can demonstrate a uniform distribution of platinum particles. In particular, the distribution of these particles is considered uniform over the size of the assembly. The color produced appears uniform to the naked eye. The color and composition are given in the table of fig. 4 with the number 1ALD 50.

The second example uses a ceramic powder based on yttria-stabilized zirconia (TZ3YS) without a binder, consisting of 3 mol%. 10g of this powder was placed in the vibrating bowl of the ALD chamber and evacuated to initiate the deposition of platinum by the ALD process. 200 deposition cycles were performed. The ceramic powder thus coated is then subjected to grinding (mixing, wet grinding) and binding processes. In this treatment, 0.6g of PVA, 0.9g of PEG 20000 and 120ml of deionized water were added to 50.4g of the platinum coated ceramic powder. The suspension thus obtained was placed in the zirconia bowl of a mill with 1kg of zirconia beads and milled/milled at a speed of 400rpm for 2 hours. The suspension is then recovered for drying and granulation by spray drying using a "spray dryer". The granules thus obtained are then pressed into a cylindrical mould on a uniaxial press. The resulting pellets were degreased in air at 600 ℃ for 18 hours. Finally, it was sintered in air at 1450 ℃ for 2 hours. After sintering, the surface of the ceramic pellet is ground and then polished. The ceramic component obtained is grey in colour. Fig. 3 is an image of the sintered ceramic pellet obtained by a Scanning Electron Microscope (SEM), which shows the distribution of platinum particles (bright spots). The figure can demonstrate a uniform distribution of platinum particles. In particular, the distribution of these particles is considered uniform over the size of the assembly. The color produced appears uniform to the naked eye. The color and composition are given in the table of fig. 4 as number 2ALD 200.

The table in fig. 4 shows the results of the previous example. It is noted that all these embodiments enable grey ceramics to be obtained. In general, therefore, one embodiment of the invention advantageously enables the manufacture of grey ceramics, characterized by two parameters a and b ranging from-1 to 1 (inclusive).

As a variant, one embodiment of the invention enables the manufacture of grey ceramic components, characterized in that the two parameters a and b are-3 to 3 inclusive, or even-2 to 2 inclusive, or even-0.5 to 0.5 inclusive.

It should be noted that the wear after the addition of platinum is better able to disperse the platinum in the material and does not significantly change the colour of the ceramic obtained in these examples. A very slight increase in the density of the sample associated with abrasion was also observed. However, this wear is still optional.

Naturally, the invention is not limited to the manufacture of ceramic components comprising platinum as the added compound. The grey colour can be obtained with other compounds than platinum, for example with rhodium, palladium or any other grey precious metal that does not react with other components of the ceramic or the sintering atmosphere. Furthermore, the present invention is not limited to the manufacture of ceramic components of a particular color. In fact, multiple colors can be obtained by varying the compounds added. It was observed that the addition of iron Fe produced a very yellowish ceramic. The addition of chromium Cr to the pure stabilized zirconia also produces a yellow ceramic with a slight red tendency. Chromium deposited on zirconia to which 2 wt% alumina has been added will result in a lighter but redder material. The addition of vanadium V makes the ceramic yellow, while the addition of aluminum Al has little effect on the primary color.

Alternatively, the manufacturing method may comprise a previous step E1 of adding another compound to the ceramic powder without binder, for example, adding a coloring pigment or any other compound according to the above-mentioned conventional method or according to other techniques known to the person skilled in the art (e.g. by salt precipitation). Indeed, the present invention remains compatible with all other existing methods and can be complementary thereto, e.g. for enriching them. This step E1 may be performed at any suitable time during the manufacturing process. It may be performed before or after step E3.

According to another variant and optionally, the manufacturing method may comprise: after the previously described deposition step E3, a subsequent step E4 of adding another added element or compound to the ceramic powder with the binder. In this case, the deposition step E3 by ALD process can make the surface of the ceramic powder electrically conductive, for example by adding further metal compounds. This provides the advantage of limiting the risk of agglomeration of the ceramic powder, in particular in PVD chambers for carrying out physical vapour deposition (abbreviated PVD), since the particles of such ceramic powder with binder have electrostatic properties which tend to agglomerate them together and form agglomerates naturally, which is disadvantageous for subsequent coating with added compounds. It should be noted that the first conductive further compound need not cover the entire surface of the powder particles to be effective. It should be noted that such other additional compounds deposited by any technique PVD, CVD or ALD may be the same as the compounds deposited by ALD deposition. As a variant, the two further compounds deposited are different in order to combine their properties.

As mentioned above, prior art solutions for colouring ceramic components are complex and not always satisfactory. Furthermore, when it is desired to change (even slightly) the hue by using ceramic components pre-coloured with pigments according to the prior art, it seems difficult to do with conventional techniques, in particular because the pigments tend to react with each other during sintering. Thus, according to the prior art, changing the intensity (brightness) and/or the hue of the color of a colored ceramic is lengthy and laborious: in fact, each attempt requires the creation of a new batch of ceramic powder with new chemical composition, followed by the production of injection molding raw material, up to the final (sintered and polished) ceramic component.

With the method of the present invention, such a change in color or intensity becomes much easier to perform. More generally, any other modification of the properties of the ceramic component is easy.

One embodiment of the invention is therefore based on a method for manufacturing a ceramic powder or a ceramic component (in particular based on zirconia and/or alumina and/or strontium aluminate), comprising the following steps:

-providing a ceramic powder (obtained according to the above-described method) with a binder comprising a coloured pigment or more generally at least one added or added compound, so that a ceramic component having a first colour or more generally a first property can be obtained by manufacturing a ceramic component from such a ceramic powder with a binder;

-depositing at least one coloured or added element or compound E3-E4 on the ceramic powder with binder by physical vapour deposition PVD and/or by chemical vapour deposition CVD and/or by atomic layer deposition ALD;

-completing the manufacturing of the ceramic component from the ceramic powder with binder comprising the deposited added compound to obtain the ceramic component, the color of which is a second color different from said first color, or more generally the ceramic component has a second property different from the first property.

By this method, the first property obtained from the ceramic powder having the binder can be easily changed to the binder having the second property by adding the added compound according to the embodiment of the present invention. Since this embodiment of the invention uses step E3, which is easy to implement, control and reproduce, it is easy to perform several tests to obtain the desired final properties of the ceramic component by trial and error, without the need for laborious interventions at the stage of ceramic powder preparation.

Thus, the method for manufacturing a ceramic component may repeat the following steps: depositing at least one additional compound on the ceramic powder with binder, varying the content of the additional compound or even of the additional compound itself, and completing the manufacture of the ceramic component until sufficiently close to the desired result.

Thus, in practice, the following steps can thus be realized: the ceramic powder with a binder containing a colouring pigment is selected which is capable of obtaining a first colour close to a desired second colour, and then the colour is changed by adding further colouring compounds until it has been sufficiently close to the desired colour. As previously mentioned, the same method can be implemented to change any property other than color.

Advantageously, the at least one added compound is chosen so as not to react with the added compound (for example a colouring pigment) already present in the ceramic powder with binder.

The pigment present in the ceramic powder with the binder may comprise one or more elements selected from metal oxides and/or rare earth oxides and/or cobalt aluminate and/or phosphorescent pigments.

More generally, embodiments of the present invention are readily compatible with all other techniques of adding at least one compound to ceramic powders with or without binders. Thus, the present invention can be combined with any other technique, in particular with conventional methods, to obtain any type of ceramic with novel properties.

Furthermore, the colour of the ceramic component is particularly important for a timepiece or jewelry part, since it allows to achieve the desired aesthetic effect. The invention is therefore particularly advantageous for the manufacture of timepiece or jewelry parts. The timepiece component may be, in particular, a bezel, a dial, an indicator, a winding crown, a push button or any other timepiece housing element or timepiece movement element. The invention also relates to a timepiece, in particular a wristwatch, including such a timepiece assembly.

naturally, the invention is not limited to a specific color, nor to a given performance of the ceramic component. In fact, the concept of the invention is to increase and simplify the possible enrichment of ceramic components, and the invention finally enables the manufacture of a variety of novel ceramic components.

In particular, the ceramic component obtained by the embodiments of the present invention comprises at least one specific property obtained by a very small amount of added compound distributed in the ceramic component. This very small amount is less than or equal to 5 wt%, or less than or equal to 3 wt%, or less than or equal to 1 wt%, or less than or equal to 0.05 wt%, or less than or equal to 0.01 wt%, relative to the total weight of the final ceramic compound. Furthermore, this content (excluding organic compounds) will advantageously be greater than or equal to 1ppm, or greater than or equal to 10 ppm.

The invention further relates to a device for producing a ceramic component, wherein the device uses a method for producing a ceramic component. To this end, the manufacturing apparatus comprises means for performing Atomic Layer Deposition (ALD) and optionally Physical Vapor Deposition (PVD) or Chemical Vapor Deposition (CVD).