Cermet timepiece or jewelry components

Abstract

To provide a cermet with an optimized composition to meet criteria of: having high metallic brilliance; having a minimum hardness of 700 HV30; avoiding the use of allergenic elements such as nickel or cobalt; not having ferromagnetism; and being resistant to saline corrosion.SOLUTION: A nickel- and cobalt-free non-ferromagnetic component, in particular for a timepiece or jewel, is made of a cermet material comprising a carbide phase and a phase of a metallic binder that is selected from one of silver, gold, platinum, palladium, rhodium, osmium, ruthenium, and an alloy of them. The metallic binder phase is present in the range from 6 to 25 wt.%. The carbide phase is of molybdenum carbide and is present in the range from 75 to 94 wt.%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention is particularly directed to a ceramic substrate having a ceramic phase containing carbides and a metal binder containing a noble metal. The present invention relates to components for timepieces or jewelry made of a met type material. [Background technology]

[0002] Many exterior components are made from gold or gold alloys. Gold is highly ductile and malleable. It has the advantage of being easy to mold and has a very noble and distinctive metallic luster. Furthermore, different gold alloys can exhibit a variety of shades ranging from white to red. However, gold and its alloys have the disadvantage of having low hardness, at most 300HV. In this regard, various ceramic composites have been developed to increase the hardness of gold. In most cases, the manufacturing process involves infiltrating gold into a hard matrix and applying very high pressure The drawback of this process is that the accessible shapes are limited to simple geometric shapes. To obtain complex geometries, which remain limited to the use of additional machining methods, Further processes disclosed in document WO 2004 / 005561 consists in using gold as a metal binder in a cermet obtained by sintering The gold metal binder is present in a proportion much greater than 50% by weight. The hardness of noble cermets is low and inversely proportional to the weight percentage of gold. The PET bottle uses non-noble metals as binders. This is described in the document U.S. Pat. No. 4,589,917 The allergenic elements such as nickel or cobalt disclosed in the patent application, or low tolerance They often contain iron-based alloys that provide corrosion resistance and high ferromagnetic properties. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2004 / 005561 [Patent Document 2] U.S. Patent No. 4,589,917 Summary of the Invention

[0004] The object of the present invention is to provide a method for the treatment of a disease comprising the following criteria: - have a high metallic luster; - have a minimum hardness of 700HV30, - Avoiding the use of allergenic elements such as nickel or cobalt, - non-ferromagnetic and resistant to salt corrosion; By proposing a cermet with an optimized composition to satisfy the above-mentioned The key is to overcome the points.

[0005] For this purpose, the present invention provides a method for producing a carbide phase and a metal of silver, gold, platinum, palladium, ruthenium, a metal binder phase selected from one of osmium, rhodium, and alloys thereof; It is proposed to provide components for timepieces or jewellery made of cermet materials, including: The alloy phase is present in a weight percentage of 3 to 25%, and the carbide phase is present in a weight percentage of 75 to 97%. Present in weight percentages.

[0006] The cermet materials developed in this way are highly abrasive, especially when the metal binder is palladium. After polishing, they have a metallic luster comparable to that observed on stainless steels. It has a hardness of 700 to 1900 HV30 and is tough enough for the production of exterior parts. Furthermore, to obtain "near net shape" parts, conventional methods such as pressing and injection are used. It can be formed by powder metallurgy processes.

[0007] The low content of noble binders preserves the reflective and colorimetric properties of the carbides used. It is now possible to obtain cermets with excellent mechanical properties, which are particularly useful for exterior parts and decorative components. is important.

[0008] The present invention also provides a method for producing a medicament for the treatment of a medicament comprising the following steps: a) Carbide powder and silver, gold, platinum, palladium, ruthenium, osmium, rhodium, and a powder of a metal binder selected from one of forming a mixture including an additive; b) forming a blank by giving said mixture the shape of a component; Pu and, c) Sintering the blank at a temperature of 1000 to 1900°C for a period of 30 minutes to 10 hours. and a step of forming a carbon fiber composite. The weight percentage of the oxide powder is 75 to 97% and the weight percentage of the metal binder powder is 3 to 25%. The additive is present in a weight percentage of 0 to 4%. It is a sign.

[0009] The use of noble binders such as platinum and palladium makes these carbide-based cermets Without the use of high temperature and pressure sintering, the carbide can be sintered at a much lower temperature than the carbide alone. From 1250°C using palladium, from 1400°C using platinum, It becomes possible to densify.

[0010] The powder of the mixture is preferably less than 20 μm, more preferably less than 10 μm, even more preferably Preferably with a d50 of less than 5 μm. Small particle size improves blend uniformity This ensures excellent coverage of the metal binder on each carbide particle. By reducing the amount of sintering, mechanical properties such as hardness and toughness can be improved while the final density can be improved. Furthermore, by reducing the particle size, it is possible to obtain a high metallic luster, i.e. , high brightness value L * It becomes possible to obtain

[0011] Further features and advantages of the present invention will be given by way of non-limiting example with reference to the accompanying drawings, in which: This will become apparent in the following description of the preferred embodiment. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating a timepiece with a middle made of a cermet-type material according to the invention. [Figure 2] FIG. 2 is an electron microscope image of a cermet-type material of the composition according to the invention (80% Mo2C-15% Au and 5% Cu). [Figure 3] FIG. 3 is an electron microscope image of a cermet-type material of a further composition (80% TiC-2% SiC-18% Pt) according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention is based on a mixture of a carbide phase, which constitutes the majority of the alloy, and other metals such as silver, gold, platinum, palladium, ruthenium, and osmium. containing precious elements such as aluminum, rhodium, or alloys of any of these precious elements and a metal binder phase in an amount of 0.1% by weight. Preferably, the metal binder is silver, gold, platinum, palladium, or The component according to the present invention is selected from an alloy of any of these precious elements. It can be used to form ornaments such as watches, jewelry, bracelets, and other components. In watchmaking, these components include the middle, back, bezel, push-pieces, and bracelet. External parts such as the thread links, dial, hands, and dial indexes. It may also consist of components of the movement such as a movement plate. A middle 1 made of a cermet-type material is shown in FIG.

[0014] Cermet components are produced by sintering a mixture of carbide powder and metal powder. This manufacturing process includes the following steps a), b), and c).

[0015] a) Optionally, in a humid environment, create a mixture with a different powder. is preferably less than 20 μm, more preferably less than 10 μm, even more preferably less than 5 μm The mixture is optionally milled to obtain the desired d50. The particle size distribution can be measured according to the ISO 13320:2020 standard. It is measured by laser diffraction.

[0016] The mixture is from 75 to 97%, advantageously from 78 to 97%, more advantageously from 78 to 97%, by weight. to 94% carbide powder and 3 to 25%, advantageously 3 to 22%, more advantageously 6 to 22% metal powder. The mixture optionally contains 4% of all additives. It may contain one or more additives in the following weight percentages: If more than one additive is present, the additive is preferably less than 100% by weight relative to all of the additives. More specifically, one or more additives are present in an amount of 1 to 3%. In the presence of, the mixture is mixed with carbide powder in a weight percentage of 75 to 96% and metal sintered body. The powder mixture is added in a weight percentage of 3 to 24% of the total additives. , in a weight percentage of 1 to 3%. These additives improve densification during sintering. For example, these additives are Si2Ti or Si2Zr. It may be made of a metal disilicide.

[0017] Preferably, the carbide powder is selected from TiC, SiC, Mo2C, WC, and NbC. More specifically, the carbide powder contains one or more carbides as the main component. Titanium carbide (TiC), tungsten carbide (WC), or molybdenum carbide (Mo2C) Contains as the main component means that if there are several types of carbides in the powder, Tungsten (TiC), tungsten carbide (WC), or molybdenum carbide (Mo2C) are other This means that Mo2C exists in a higher percentage than carbides. It can contain Mo2C and TiC, which are the main components. It can contain Mo2C and TiC as components. It may contain TiC and SiC present as components. The metal powder can be composed of only TiC, WC, or Mo2C. as palladium, platinum, silver, gold, ruthenium, osmium, rhodium, or any of these elements Contains any alloy of any of the elements, excluding impurities, platinum, palladium, ruthenium, The gold may be composed solely of Cu, Ag, Pd, or rhodium. In addition, the alloy is preferably formed with at least one element selected from the group consisting of gold, silver, tungsten, tungsten, and indium. Alloys include gold alloys with silver and copper (3N yellow gold, 5N red gold), or Contains gold alloys with palladium (white gold). Metal powders are also used in powder mixtures. It may contain carbon in a weight percentage of 0.1 to 5% based on the total weight. In this case, part of the Mo2C may be converted to Mo during sintering, which may reduce the hardness. Adding Mo can limit the formation of Mo, thus maintaining the hardness level. Carbon can be added to the carbide powder. Thus, the carbide powder accounts for 100% of the total weight of the powder mixture. It contains carbon in a weight percentage of 0.1 to 5%.

[0018] By way of example, the powder mixture may include one of the following weight distributions:

[0019] - 80 to 95% TiC and 5 to 20% Pd or Pt, - 75 to 95% TiC and 5 to 25% Au alloy, - 50 to 70% TiC, 5 to 30% Mo2C, and 5 to 30% Au alloy Preferably, the composition is 55 to 65% TiC, 10 to 25% Mo2C, and 5 to 65% TiC. 25% Au alloy, - 70 to 85% TiC, 5 to 10% Mo2C, 5 to 20% Pd or Pt, - 75 to 85% TiC, 2 to 10% SiC, and 5 to 23% Pd or Pt, - 80 to 97% Mo2C and 3 to 20% Pd, Pt, Ag, or Au alloys , - 75 to 95% Mo2C and 5 to 25% Au alloy, - 75 to 95% WC and 5 to 25% Pd or Pt, - 80 to 95% WC and 5 to 20% Au alloy. Optionally, a mixture of the above and an organic binder system (paraffin, polyethylene, etc.) A second mixture can be made.

[0020] b) adding the desired components to the mixture, for example by injection or by pressing into a mold; A blank is formed by giving it a shape.

[0021] c) Blanks are heated in an inert atmosphere or vacuum at a temperature of 1000 to 1900°C for 30 minutes. The mixture is sintered for a period of 30 minutes to 10 hours, preferably 30 minutes to 5 hours. If so, prior to this step, one or more A degreasing step can be performed.

[0022] The blank thus obtained is cooled and polished. It is also possible to perform a process to obtain the desired component.

[0023] The resulting component, also called a molded part, from this manufacturing process is the weight percent of the initial powder. It contains carbide and metallic phases in weight percentages approaching 0.01%. However, there are some problems with subsequent sintering, such as contamination or alteration, e.g., from Mo2C to Mo. It is possible to eliminate slight variations in composition and percentage between the base powder and the material. Therefore, the final product from the process will have a high mass percentage of the various phases. The carbide phase must be distinguished from the metal phase, also called the metal binder. The carbide phase is not only a carbide but also a derivative of the basic carbide powder, such as Mo in the above example. Similarly, for the metal phase, the compound of the initial metal powder as well as any compounds resulting from the decomposition or reaction of the metal-based powder. If additives are present in the final mixture, they are detected in the carbide and / or metal phases. It is possible.

[0024] The components are (CIE No. 15, ISO 7724 / 1, DIN 5033 Te il 7, CIELAB color space (in accordance with ASTM E-1164 standard) and materials The luminance component L, which represents how light is reflected * 60 to 90, preferably 65 to 8 5, more preferably 70 to 85.

[0025] Ceramic materials range from 700 to 1900 kJ depending on the type and percentage of ingredients. It has a hardness of HV30. More specifically, the carbide phase contains molybdenum carbide as the main component. If present, the hardness is 700 to 1300 HV30. When tungsten oxide is contained, the hardness is 900 to 1600 HV30, and the carbide phase However, when titanium carbide is contained as the main component, the hardness HV30 is 700 to 1900. do.

[0026] Ceramic materials must have a strength of at least 2 MPa.m 1 / 2 of 20MPa.m 1 / 2 exceed Possible toughness K i c. The toughness is calculated by the Vickers hardness implied by the following formula: The crack length is determined based on crack length measurements at the four ends of the diagonal of the crack.

[0027] JPEG0007819240000001.jpg13170

[0028] where P is the applied load (N), a is the semi-diagonal (m), and l is the measured crack length. It is (m).

[0029] Tables 1 to 3 below contain various examples of cermets according to the present invention.

[0030] 27 powder mixtures were prepared in a mill in the presence of a solvent. The mixtures were prepared without a binder. They were compressed into chips by uniaxial pressing and then dried in a vacuum or powder composition. The samples were sintered under argon partial pressures of 5 to 100 mbar at temperatures dependent on the sample. The tool was mechanically polished flat.

[0031] Table 1 shows the carbide phases containing TiC, Mo2C or TiC and Mo2C, and Pd, Au Test Nos. 1 to 9 include a binder phase containing an Au alloy. Test No. 7 includes M 0.5% C is added to limit the formation of o.

[0032] Table 2 shows the carbide phases containing TiC, TiC and SiC, or Ti and Mo2C. Test Nos. 11 to 18 include a binder phase containing Pt or Pd. In this case, the powder mixture contains an additive that improves densification. This additive is present at a weight percentage of 2%. The compound is Si2Ti.

[0033] Table 3 shows the results of the comparison of carbide phases containing Mo2C or WC with Pd, Pt, Ag, Ag alloys or A Test Nos. 19 to 27 include a binder phase containing an alloy.

[0034] HV30 hardness measurements were performed on the surface of the samples, and the toughness was determined based on the above hardness measurements. It was.

[0035] Lab colorimetric values ​​are measured under the following conditions: SCI (including specular component) measurement and SCE (Specular component excluded) Measurement, tilt 8°, MAV measurement zone 8mm diameter, KONI Measured on polished samples using a CA MINOLTA CM-5 spectrophotometer Ta.

[0036] From these tests, it was found that the cermet with a carbide phase containing TiC as the main component It has a higher overall hardness than cermets with carbide phases containing Mo2C as a component. Therefore, the hardness of the cermet containing Mo2C as the main component is In the case of TiC-containing cermets, the HV30 values ​​are in the range of 750 to 1200. In the case of TiC and Au alloy samples, the HV30 is 750 to 1800. 4 is compared with the hardness of sample 3 (1209 HV30) containing TiC and Au alloy. As a result of the short sintering time, the sample has a low hardness (761 HV30). 4 has lower toughness compared to sample 3.

[0037] Cermets containing Mo2C and Pd have a Pd content of 8% or more and a Pd content of 10 MPa. .m 1 / 2 (Tests 6, 20, and 21) ,There was no crack propagation during the HV30 hardness measurement, and therefore, the toughness value could not be measured.

[0038] Cermets containing Mo2C as the main component are different from cermets containing TiC as the main component. In contrast to the values ​​in the range of 70-75 for the case of Pt, Pd, Ag, Au-C Regardless of the type of u), a high luminance index L of the order of 80 * It has.

[0039] 80% by mass of tungsten carbide and 20% palladium as a precious metal binder. The cermet, which is made up of only carbide, has high hardness (1472 HV30) and excellent toughness (6. 3 MPa.m 1 / 2 ) and its high density makes it possible to mount functional parts such as vibration masses. This makes them excellent candidates for generation.

[0040] Regarding the microstructure, Figure 2 shows the results of a 80% MoC, 15% Au, and 5% C alloy by weight. Electron microscope image of a sintered sample from a powder mixture containing u. The carbide phase is Mo2C It consists of a dark gray zone composed of Mo and a medium gray zone rich in Mo. During sintering, part of the Mo2C is converted to Mo, which reduces the hardness. is.

[0041] Figure 3 shows a powder mixture containing 80% TiC, 2% SiC, and 18% Pt by weight. 1 shows an electron microscope image of a sintered sample from The black zone contains TiC and the gray zone contains TiC and Pt. The metallic phase is white.

[0042] As explained above, the present invention relates to components made of cermet materials. Components are, for example, exterior parts or movement elements of timepieces, in particular those made of watches. The component according to the invention is intended for use in the fields of jewelry and watches. It is not limited to watchmaking. Thus, by way of non-limiting example, this component may be used in tableware, cutlery, etc. It could also be applied in the fields of rallying, leather goods or jewellery.

[0043] JPEG0007819240000002.jpg252170

[0044] JPEG0007819240000003.jpg247170

[0045] JPEG0007819240000004.jpg248170

Claims

1. 1. A nickel- and cobalt-free non-ferromagnetic component for a timepiece or jewelry made of a cermet material, comprising a carbide phase and a metal binder phase selected from one of silver (Ag), gold (Au), platinum (Pt), palladium (Pd), rhodium (Rh), osmium (Os), ruthenium (Ru), and alloys thereof, wherein the metal binder phase is present in an amount of 6 to 25% by weight, and the carbide phase is molybdenum carbide and is present in an amount of 75 to 94% by weight, when the total weight of the non-ferromagnetic component is taken as 100% by weight percentage. 20% weight percentage of an alloy consisting of 15% weight percentage of gold and 5% weight percentage of copper, 20% weight percentage alloy consisting of 15% weight percentage gold, 3.2% weight percentage silver and 1.8% weight percentage copper, 21% weight percentage alloy consisting of 15.75% weight percentage gold, 4.2% weight percentage copper and 1.05% weight percentage silver; 20.8% by weight of an alloy consisting of 15.2% by weight of gold, 5.1% by weight of copper and 0.5% by weight of carbon; 16% weight percentage of an alloy consisting of 12% weight percentage of gold and 4% weight percentage of copper, 20% weight percentage of an alloy consisting of 15.2% weight percentage of gold and 4.8% weight percentage of copper, 22% by weight of an alloy consisting of 15% by weight of gold, 5% by weight of copper and 2% by weight of carbon; 8% weight percentage of an alloy consisting of 7.4% weight percentage of silver and 0.6% weight percentage of copper, A 10% weight percentage alloy consisting of 7.5% weight percentage gold and 2.5% weight percentage copper A non-ferromagnetic component characterized in that it is one of the following:

2. The component of claim 1 , wherein the metal binder phase is present in a weight percentage of 6 to 22% and the carbide phase is present in a weight percentage of 78 to 94%.

3. Component according to claim 1, characterized in that it has a hardness HV30 of 700 to 1900.

4. 2 MPa.m １／２ Toughness Ki Ｃ Component according to claim 1, characterized in that it has:

5. Component according to claim 1, characterized in that the luminance component L* in the CIELAB color space is between 60 and 90.

6. Component according to claim 1, characterized in that it consists of an exterior component or a movement in watchmaking.

Images