COMPOSITE MATERIAL, METHOD FOR THE PRODUCTION OF A COMPOSITE MATERIAL, AND A DISCHARGE COMPONENT INCLUDING A COMPOSITE MATERIAL

Abstract

A composite material includes a first metallic material component and a second metallic material component. The first material component is different from the second material component. The second material component is mixed with the first material component.

Claims

1. A composite material, comprising a first metallic material component, and a second metallic material component, wherein wherein the first metallic material component is different from the second metallic material component, and further wherein the second material component is mixed with the first metallic material component.

2. The composite material according to claim 1, wherein a) the first material component forms a cohesive matrix, into which the second material component is incorporated in particulate form, and/or in that b) the second material component is incorporated discontinuously, in the form of separate particles, into the first material component, and/or c) the second material component is incorporated into the first material component in the form of particles with a particle size of at least 5 m to at most 100 m, preferably up to at most 70 m, preferably up to at most 50 m.

3. The composite material according to claim 1, wherein: a) the first material component has a lower melting point than the second material component, and/or b) the second material component is more noble than the first material component.

4. The composite material according to claim 1, wherein the first material component comprises: a) a nickel-based alloy or a malleable iron alloy or consists of a nickel-based alloy or a malleable iron alloy, and/or b) nickel and chromium.

5. The composite material according to claim 1, wherein the second metallic material component comprises an element selected from a group consisting of iridium, platinum, rhodium, ruthenium, palladium and a rare earth metal, or in that the second metallic material component consists of one of these elements.

6. The composite material according to claim 1, wherein a) a portion of the second metallic material component of the composite materialin percent by weightamounts to at most 80 or b) in that a volume ratio of the second material component to the first material component amounts to at least 10:90 to at most 90:10.

7. A method for producing a composite material, the method comprising mixing a first powdered metallic material component with a second powdered metallic material component, wherein the first material component is different from the second metallic material component, and wherein the first metallic material component has a lower melting point and/or is less noble than the second material component; preparing a mixture, comprising the first material component and the second metallic material component; shaping the mixture into a molded body; and sintering the molded body, at a sintering temperature lower than the melting point of the second material component.

8. The method according to claim 7, further comprising: mixing a binder component with the first metallic material component and/or with the second metallic material component, wherein the resulting mixture comprises the first metallic material component, the second metallic material component and the binder component.

9. The method according to claim 7, wherein the sintering temperature is selected to be lower than the melting point of the first metallic material component.

10. The method according to claim 8, further comprising subjecting the molded body to a binder removal step before sintering.

11. The method according to claim 7, wherein the shaping of the mixture is carried out by a powder metallurgy method.

12. The method according to claim 7, wherein the shaping of the mixture is carried out by pressing.

13. The method according to claim 7, wherein the molded body; a) is joined to another molded body in a two-component injection molding method, wherein the additional molded body is free of the second metallic material component, or b) is joined to another molded body produced separately, said the molded body being free of the second material component, wherein the molding body and the additional molded body are sintered jointly.

14. The method according to claim 7, wherein the molded body is joined to an additional body in the form of a base body for an electrode in at least one of a form-fitting connection and a physically bonded connection.

15. A discharge component, comprising a composite material according to claim 1 or consisting of the composite material.

Description

[0160] The invention is explained in greater detail below on the basis of the drawing, in which:

[0161] FIG. 1 shows a schematic diagram of an embodiment of a discharge component with an embodiment of the composite material, and

[0162] FIG. 2 shows a schematic diagram of the functioning of the discharge component according to FIG. 1.

[0163] FIG. 1 shows a schematic diagram of one embodiment of a discharge component 1 consisting of an embodiment of a composite material 3. This composite material comprises a first metallic material component 5 and a second metallic material component 7, wherein the first material component 5 and the second material component 7 are different from one another, and wherein the first material component 5 here has a lower melting point than the second material component 7. The second material component 7 here is incorporated into the first material component 5 in particulate form. For the sake of better comprehensibility, only two particles of the second material component 7 are labeled with the reference numeral 7 here.

[0164] The first material component 5 in the exemplary embodiment illustrated here has a cohesive matrix, in which the second material component 7 is embedded in the form of the particles illustrated in FIG. 1. It can be seen here that the second material component 7 is incorporated discontinuously, i.e., in particular in the form of separate particles into the first material component 5 here.

[0165] The second material component 7 is preferably more noble than the first material component 5, which means in particular that the second material component 7 has a higher standard potential than the first material component 5. The second material component 7 in particular has a standard potential higher than zero. The first material component 5 preferably also has a standard potential higher than zero. However, it is also possible for the first material component 5 to have a negative standard potential.

[0166] The first material component 5 preferably has a nickel-based alloy or a malleable iron alloy, in particular a steel, preferably a stainless steel, or consists of one of these materials. It is preferably provided that the first material component 5 comprises nickel and chromium, wherein nickel preferably forms a main constituent of the first material component 5, and wherein chromium preferably forms one of the most important secondary constituents, in particular in the sense of a greatest amount by weight, based on all the secondary components.

[0167] The second material component 7 preferably comprises at least one element, selected from a group consisting of iridium, platinum, rhodium, ruthenium, palladium and a rare earth metal. It is possible for the second material component 7 to consist of one of the aforementioned elements. The second material component 7 preferably comprises an alloy or a combination of at least two of these elements, in particular an alloy comprising platinum and iridium or iridium and rhodium, preferably platinum-iridium or iridium-rhodium, or the second material component 7 consists of such a combination or alloy.

[0168] A portion of the second material component 7 of the composite material 3 preferably amounts toin percent by weightat most 80, preferably at most 70, preferably at most 60, preferably at most 50, preferably at most 40, preferably at most 30, preferably at most 20, preferably at most 10.

[0169] The second material component 7 is preferably in the form of particles having a particle size of at least 5 m to at most 100 m.

[0170] The composite material 3 is preferably produced by mixing the first metallic material component 5 in powder form with the second metallic material component 7, which is also in powder form. A binder component is preferably mixed with the first material component 5, with the second material component 7 and/or with the mixture of material components 5, 7. On the whole, this yields a mixture which ultimately comprises the first material component 5, the second material component 7 and preferably the binder component. This mixture is shaped to form a molded body, which is then sintered at a sintering temperature lower than the melting point of the second material component 7, preferably lower than the melting point of the first material component 5 and especially preferably from at least 0.6 to at most 0.8 multiplied times the melting point of the first material component, preferably 0.8 multiplied times the melting point of the first material component.

[0171] A homogenous mixture of the material components 5, 7 is preferably prepared, wherein the particles of the second material component 7 in particular are arranged individually between particles of the first material component 5. Sintering therefore results in a cohesive matrix of the first material component 5, in which the particles of the second material component 7 are embedded separately, in particular not cohesively.

[0172] Shaping of the mixture to form the molded body preferably takes place by pressing, extruding or powder injection molding, in particular by means of metal powder injection molding.

[0173] A molded body produced in particular by extrusion or injection of powder is preferably subjected to a binder removal step before sintering, this step optionally comprising a plurality of binder removal substeps.

[0174] It is possible for the molded body to be attached to another molded body, in particular another greenware body, in particular being integrally molded on the additional molded body, wherein the initial molded body is free of the second material component 7 and preferably comprises only the first material component 5 and optionally a binder component. A larger component can be created in one piece in this way, comprising the discharge component made of the composite material 3. For example, an electrode comprising the discharge component 1 made of the composite material 3 only in a certain region or in various certain regions can be created.

[0175] This can also be achieved by attaching the molded body in a green state, i.e., as greenware or as a greenware product, to another molded body produced separately, preferably in the form of a greenware or a greenware body, wherein the additional molded body in this case is also free of the second material component 7 and preferably comprises only the first material component 5 and preferably also a binder component. The two molded bodies in this case may also be sintered jointly.

[0176] The two molded bodies can be produced in particular in similar methods or in different methods. For example, it is possible for one of the molded bodies to be produced by powder injection molding, wherein the other molded body is produced by pressing or extrusion.

[0177] It is also possible to use a hybrid injection molding method, wherein the molded body is integrally molded on an insert, or wherein an insert is encased in the molded body. The insert can be produced by cutting by machining, for example, as a lathed part. The molded body is preferably sintered in the presence of the insert.

[0178] FIG. 2 shows a schematic diagram of the functioning of the discharge component 1 with the composite material 3. The same elements and those having the same function are labeled with the same reference numerals, so that reference is made to the preceding description to this extent.

[0179] FIG. 2 shows in particular arrows pointing to a surface 9, such as a discharge having a negative effect on the surface 9 of the discharge component, wherein the discharge leads in particular to erosion and/or corrosion of the discharge component 1 in the area of the surface 9. As already indicated schematically, this leads first to a burnoff of matrix material, and consequently of the first material component 5. Therefore, particles of the second material component 7 are exposed, so that four rows of particles A, B, C, D are represented schematically in FIG. 2a)as seen in the radial direction from the surface 9 perpendicular to interior of the discharge component. A particle 11 in the first particle row A is already partially exposed due to erosion and/or corrosion of the surface 9.

[0180] FIG. 2b) shows that, with additional application of discharges to the discharge component 1 and continued erosion and corrosion, the particle 11 is at some point released from the matrix composite of the first matrix material 5 and falls out of the surface 9as indicated by an arrow and a dash. Due to the advanced burnoff of the surface 9, the outermost row A of particles is thus released, and the second row B of particles arranged behind the former advances more or less after it and becomes the new first row of particles. Burnoff occurs essentially in the region of the less noble first material component 5, which has a lower melting point.

[0181] FIG. 2c) therefore shows that, after a certain additional application in the area where the particle 11 had previously been arranged, so much material of the first material component 5 has now burned off that additional particles from the third row C of particles have been exposed. These particles, which are more or less pushed forward, then take over the function of the particle 11 released from the surface.

[0182] It is found that with composite material 3, it is possible to provide a greater area with locally reduced wear at the same cost of materials for a discharge as if only the second material component 7 had been exposed in the area that is effective for the discharge.

[0183] The ignition energy that must be expended to form the discharge can be concentrated in small areas, in particular those of the particles of the second material component 7, so that it is possible to work with comparatively low ignition voltages. This then further reduces the wear on the discharge component.

[0184] In addition, it is found that typically only a certain wear in the form of a radial burnoff zone of typically approx. 200 m is acceptable for discharge components, after which the discharge component 1 or even the entire electrode must be replaced. It is now possible to use the composite material 3 over only this so-called burnoff zone as the discharge component on an electrode and to form a remaining greenware product of the electrode from an inexpensive material, for example, from the first material component 5. After burnoff of the discharge component is finished, there remains only the inexpensive first material component 5 for disposal, so that a corresponding electrode with a discharge component 1 is considerably less expensive than an electrode that comprises, on the whole, an expensive material that is also more stable.