Multicolour ceramic assembly and method for manufacturing thereof

Abstract

The invention relates to a polychrome ceramic assembly and to a method for manufacturing the same.

Description

Technical Field

[0001] This invention relates to a ceramic component. More specifically, it relates to a watch component produced by forming a multi-colored integrated watch component from colored ceramic materials through spark plasma sintering (SPS). Background Technology

[0002] Ceramic or cermet watch components are typically manufactured using injection molding or methods involving uniaxial or isostatic pressing of material followed by sintering. These components are often decorated in a different color than the rest of the component or simply feature a two-tone finish, such as hour markers and numerals on the dial or bezel. Decorative elements on the bezel are often added by inlaying or filling sintered semi-finished watch movements. This mechanical assembly between the semi-finished movement and the decorative elements can be expensive and complex.

[0003] An alternative to this mechanical assembly is to produce semi-finished watch movements by injecting materials of different colors, with the decorative color revealed after machining. However, manufacturing ceramic or cermet components of different colors is a complex process. For example, document JP59910502 describes an injection molding process using ceramic powder bonded with an organic binder. The disadvantage of this method is its complexity, as it involves numerous steps, particularly the preparation of the binder-containing powder (which requires a debinding step), and one or more auxiliary steps to obtain the desired final color.

[0004] Document EP 2 965 713 also describes a method for obtaining color-gradient ceramic materials and forming dental restorations. However, this method uses isostatic pressing, which is typically time-consuming and demanding. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings by proposing a new manufacturing method for producing multicolor ceramic components.

[0006] Therefore, the present invention relates to a method for manufacturing multicolor ceramic components.

[0007] More specifically, the method for manufacturing multi-color components according to the present invention includes the following steps: - Prepare several ceramic or cermet powders, wherein the ceramic powders differ from each other in their composition and / or color, and the powders contain only ceramic elements, carbides, nitrides, oxides or mixtures of these elements; -Provide molds; - Deposit the powder into the mold; - Sintering temperature between 600-1800°C and between 5-250 N / mm 2Rapid sintering or spark plasma sintering cycles are performed under sintering pressure to achieve a complete cycle time between 10 and 180 minutes to form multicolor ceramic components. - Demold the obtained multi-colored components; - Apply finishing to the multi-colored component.

[0008] The present invention also relates to multicolor ceramic components produced by the manufacturing method.

[0009] Other advantageous variations according to the invention: - After the demolding step, perform heat treatment such as annealing in stages in air or reagent gas at 550-1,100°C for 30 minutes to 8 hours; - The ceramic or cermet powder is selected from zirconium oxide powder, alumina powder, titanium nitride powder, silicon nitride powder, titanium carbide powder, tungsten carbide powder, or a mixture of at least two of these powders; - One or more ceramic powders contain one or more different pigments that give ceramics different colors; -The pigment is cerium sulfide; -The pigment is a metal oxide, perovskite, or spinel; - The pigment is selected from chromium oxide, cobalt oxide, iron oxide, titanium oxide, manganese oxide, molybdenum oxide, cerium oxide, vanadium oxide, zinc oxide, aluminum oxide, or mixtures of these oxides; - Cobalt / iron / chromium spinel or cobalt / aluminum spinel; -The method includes a powder preparation step, wherein the powder is mixed, homogenized or ground in an aqueous or alcoholic solution; - Atomize the ceramic powder after the powder preparation step; - Powder is deposited in a mold using a selective powder deposition system to form several layers, each containing several types of powder; - Place the mesh into the mold before the mold filling step; - The sintering process is carried out in a vacuum or in an inert or reactive atmosphere.

[0010] The present invention also relates to an integral ceramic component with a multi-colored appearance.

[0011] The components of this invention comprise several different ceramic materials that differ in composition and / or color, and more generally in their aesthetic appearance. According to the invention, the decorated component is multicolored and manufactured in a single piece. Attached Figure Description

[0012] Other features and advantages of the invention will become apparent from the following detailed description, given with reference to the accompanying drawings, in which: - Figure 1 A schematic diagram of the manufacturing method of the present invention is shown.

[0013] - Figures 2a-2c Examples of multicolor ceramic components produced using the manufacturing method of this invention are described below. Detailed Implementation

[0014] This invention relates to a ceramic component, such as an external part for a watch or jewelry, or even a watch component that is multicolored overall.

[0015] The method of the present invention is in Figure 1 The diagram illustrates the method. It is characterized by a combination of various "raw material" powders, such as juxtaposition and / or stacking, followed by a step of sintering all the powders together.

[0016] In this description, "raw material" powder refers to powder that does not contain any polymer binders.

[0017] The components of this invention are made of ceramic. For example, it can be a ceramic or a mixture of these ceramics made of zirconium oxide, alumina, titanium nitride, silicon nitride, or even carbides such as titanium carbide or tungsten carbide.

[0018] More generally, "ceramics" refers to a ceramic matrix containing stabilizers, additives or sintering aids, and optionally, pigments. For example, for an oxide matrix such as ZrO2, Y2O3 can be added as a stabilizer, Al2O3 as an additive, and Fe2O3 as a pigment.

[0019] At least one ceramic powder contains at least one pigment for coloring the material. The pigment is a metal oxide, spinel, perovskite, or even cerium sulfide, selected according to the desired color. Non-limiting examples include chromium oxide, cobalt oxide, iron oxide, titanium oxide, manganese oxide, zinc oxide, molybdenum oxide, cerium oxide, vanadium oxide, aluminum oxide, or mixtures of these oxides such as iron oxide / chromium. For example, for blue, the pigment could be cobalt oxide; for green, the pigment could be chromium oxide; and for brown, the pigment could be iron oxide.

[0020] The component of this invention can also be a constituent element of decorative components such as watches, jewelry, and bracelets. In the field of watchmaking, this component can be an external part such as the watch case frame, case back, pendant box, bezel, bezel insert, pushers, crown, bracelet links, clasp, buckle, dial, hands, dial hour markers, mainplate, bridges, etc. It can also be a component in the movement such as the rotor, mainplate, etc. As a further example, it can be a mark on the crown or even an hour marker on the bezel.

[0021] This component is made by placing various powders into a mold and then rapidly sintering or SPS (spark plasma sintering) them to form a ceramic component with a multi-colored appearance.

[0022] This manufacturing method is referenced. Figure 1 Includes the following steps: - Prepare several ceramic or cermet powders, wherein the ceramic or cermet powders differ from each other in composition and / or color, and the powders contain only carbides, nitrides, oxides or mixtures of these elements; - Provide molds designed to hold ceramic powder; - Fill the mold with ceramic powder according to the desired pattern and color, wherein the height of the deposited material mixture does not exceed the height of the mold; - Perform rapid sintering or SPS; - Demold the resulting ceramic components; - Apply finishing to the multi-color component 1.

[0023] Optionally, after the demolding step, the watch can be annealed in air in stages at 550-1,100°C for 30 minutes to 8 hours to remove any graphite covering the semi-finished watch movement.

[0024] Several layers of mixed ceramic materials can be stacked or juxtaposed to form a specific color pattern visible from the side of the component.

[0025] According to one embodiment of the invention, a mesh or template is placed in the mold prior to the mold filling step. The mesh or template is used to partition the mold and create a pattern that remains after sintering during the filling process, wherein the mesh or template is removed prior to the sintering step.

[0026] According to another embodiment, powder is deposited in a mold using a selective powder deposition system to form several layers, each containing several types of powder.

[0027] The ceramic powder consists only of carbides, nitrides, oxides or mixtures of these elements and does not contain any polymer binder.

[0028] In the powder preparation step, the powder is mixed, homogenized, or ground in an aqueous or alcohol-based solution. Homogenization (or grinding) is typically performed using a grinder or ball mill. Preferably, an aqueous solution is used if the ceramic powder contains metal oxide pigments, and an alcohol-based solution is used for cermets.

[0029] After homogenization, the powder is atomized or dried. Atomization allows for the formation of spherical particles containing various components of the ceramic powder and yields a very uniform powder.

[0030] The method includes step d), in which the powder assembly undergoes rapid sintering (or SPS) to produce a multicolor ceramic assembly corresponding to the final part. Temperature and pressure conditions can be adjusted according to the powder type and / or the expected final properties of assembly 1.

[0031] According to one embodiment, the sintering step is carried out in a vacuum at a temperature between 600 and 1,800°C.

[0032] The sintering step also includes 5-250 N / mm 2 The mechanical pressure. This mechanical pressure can be constant or can have controlled variations, such as various thresholds or ramps with increments or decrements.

[0033] A complete cycle in the sintering stage lasts between 10 and 180 minutes. A sintering cycle refers to heating, holding, and cooling.

[0034] The temperature is typically reached at a rate of 50-500°C / minute to achieve the sintering temperature.

[0035] Once sintering is complete, step e) consists of demolding the resulting multi-colored components, with the colors appearing directly after sintering.

[0036] Optionally, after the demolding step, heat treatment may be performed, such as annealing in stages in air or reagent gas at 550-1,100°C for 30 minutes to 8 hours.

[0037] As required by those skilled in the art, the component can be machined after sintering to correct its dimensions.

[0038] After any dimensional determination, the manufacturing method includes a finishing step (f) of the component. This finishing step may involve one or more methods such as satin finishing, polishing, guilloché engraving, Geneva stripes, circular texture finishing, hammer finishing, matte finishing, or any other method known to a skilled craftsman.

[0039] The method of this invention is typically used to produce [products based on] the present invention. Figures 2a-2c The dial 1 has a multi-colored appearance. Of course, other multi-colored watch components, such as external components or movement components for watches, can be obtained using the method of this invention. Therefore, the case frame, case back, pendant box, bezel, bezel insert, pushers, crown, bracelet links, buckle, dial, hands, dial hour markers, rotor, bridges, or even the mainplate can be produced using the method of this invention.

Claims

1. A method for manufacturing a multi-color integrated ceramic component, the method comprising the following steps: - Prepare several ceramic or metal-ceramic powders, wherein the ceramic or metal-ceramic powders differ from each other in their composition and / or color, and the powders contain only ceramic elements, carbides, nitrides, oxides or mixtures of these elements; -Provide molds; - Deposit the powder into the mold; - Sintering temperature between 600-1800°C and between 5-250 N / mm 2 Rapid sintering or spark plasma sintering is carried out under sintering pressure to achieve a complete cycle time between 10 and 180 minutes to form multicolor ceramic components; - Demold the obtained multi-colored components; - Apply finishing to the multicolor ceramic component (1).

2. The manufacturing method according to claim 1, characterized in that... After the demolding step, heat treatment is performed, such as annealing in stages at 550-1,100°C for 30 minutes to 8 hours in air or reagent gas.

3. The manufacturing method according to claim 1, characterized in that... The ceramic or cermet powder is selected from zirconium oxide powder, alumina powder, titanium nitride powder, silicon nitride powder, titanium carbide powder, chromium carbide powder, tungsten carbide powder, or a mixture of at least two of these powders.

4. The manufacturing method according to claim 1 or 2, characterized in that... At least one or more ceramic powders contain one or more different pigments that give ceramics different colors.

5. The method according to any one of the preceding claims, characterized in that... The pigment is a metal oxide, perovskite, or spinel.

6. The method according to claim 4, characterized in that... The pigment is selected from chromium oxide, cobalt oxide, iron oxide, titanium oxide, manganese oxide, molybdenum oxide, cerium oxide, vanadium oxide, zinc oxide, aluminum oxide, or mixtures of these oxides.

7. The method according to claim 4, characterized in that... The pigment is cobalt / iron / chromium spinel or cobalt / aluminum spinel.

8. The method according to claim 4, characterized in that... The pigment is cerium sulfide.

9. The method according to any one of the preceding claims, characterized in that... It includes a powder preparation step in which the powder is homogenized or ground in an aqueous or alcoholic solution.

10. The method according to any one of the preceding claims, characterized in that... The powder is atomized after the powder preparation step.

11. The method according to any one of the preceding claims, characterized in that... Powder is deposited in the mold using a selective powder deposition system to form several layers, each containing several types of powder.

12. The method according to any one of the preceding claims, characterized in that... Place the mesh into the mold before the mold filling step.

13. The method according to any one of the preceding claims, characterized in that... The sintering step is carried out in a vacuum or reagent gas.

14. A ceramic component, characterized in that... It has a multi-colored appearance.

15. The component according to claim 13, characterized in that The component is used as an external part or as a watch component in the movement.

16. The component according to claim 13 or 14, characterized in that Watch components used as external parts or in the movement are selected from a list including the case frame, case back, bezel, bezel insert, pushers, crown, bracelet links, buckle, dial, hands, dial hour markers, rotor, and mainplate.

Images