EP2576103A1 - Method for generating a closed-pore metal foam and component which has a closed-pore metal foam - Google Patents

Method for generating a closed-pore metal foam and component which has a closed-pore metal foam

Info

Publication number
EP2576103A1
EP2576103A1 EP11722373.5A EP11722373A EP2576103A1 EP 2576103 A1 EP2576103 A1 EP 2576103A1 EP 11722373 A EP11722373 A EP 11722373A EP 2576103 A1 EP2576103 A1 EP 2576103A1
Authority
EP
European Patent Office
Prior art keywords
metal
metal foam
molecules
composite
closed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP11722373.5A
Other languages
German (de)
French (fr)
Inventor
Frank Heinrichsdorff
Jens Dahl Jensen
Ursus KRÜGER
Gabriele Winkler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP2576103A1 publication Critical patent/EP2576103A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/11—Making porous workpieces or articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/11—Making porous workpieces or articles
    • B22F3/1121—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers
    • B22F3/1134—Inorganic fillers
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/08—Alloys with open or closed pores
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12014—All metal or with adjacent metals having metal particles
    • Y10T428/12153—Interconnected void structure [e.g., permeable, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
    • Y10T428/131—Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
    • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
    • Y10T428/1355—Elemental metal containing [e.g., substrate, foil, film, coating, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/30—Self-sustaining carbon mass or layer with impregnant or other layer

Definitions

  • the invention relates to a method for producing a closed-cell metal foam, in which a composite of a metal or a metal alloy and a blowing agent is provided. This composite is subjected to adalebe ⁇ treatment, wherein the heating of the composite sufficient to cause the blowing agent forms with the formation of pores in the composite Senen CLOSED ⁇ a propellant gas. This means that the closed pores are created by the propellant gas being formed and trapped in the forming closed pores.
  • the invention relates to a component which consists at least partially of a closed-cell metal foam.
  • a component with a component of a closed-Me ⁇ tallschaums and a method for its production is known for example from US 5,151,246.
  • the component may for example consist of a sleeve, is housed in the interior of the closed-cell metal foam.
  • blowing agents are used, such.
  • metal hydrides especially titanium hydride or carbonates, such as. For example, calcium carbonate.
  • a composite is produced, which may for example consist of particles of both substances and is compacted by pressing.
  • This green body thus formed can then be subjected to a heat treatment, wherein the temperature must be high enough so that on the one hand a connection between the individual powder particles of the metal takes place and on the other hand, the propellant forms a propellant gas.
  • the temperature must be high enough so that on the one hand a connection between the individual powder particles of the metal takes place and on the other hand, the propellant forms a propellant gas.
  • the propellant forms a propellant gas.
  • at least diffusion processes between the particles must be made possible.
  • a sufficient warming of the metallic substance must take place.
  • Particles of metals which have a solidus temperature of up to 660 ° can be foamed in the abovementioned propellants.
  • Metal foams are used for example for sealing Gezzau ⁇ sepatenteden. According to WO 2008/145173 Al this is z. B. advantageous in gas discharge lamps, which are mounted in a lamp body. In order to enable electrical contact, contacts must be led out of the lamp body, whereby a hermetic seal of these bushings must be ensured so that no oxygen enters the interior of the lamp. The completion of the implementation between lamp body and metal electrode can be done reliably by means of a metal foam.
  • the selected propellant must be chosen with regard to whether ⁇ ner thermal properties (or the foaming metal alloy) that it fits to the solidus temperature of the foaming metal.
  • the temperature difference between the solidus temperature of the metal and the lower temperature at which the propellant releases the propellant must not exceed 120 ° C. This is the only way to ensure that a metal foam is reliably formed. If we talk about metal foams in the following, foams made of metal alloys are also to be understood here.
  • the object of the invention is to provide a method for producing a closed-cell metal foam and a building Specify with such a closed-cell metal foam, in which metals with solidus temperatures of more than 660 ° C can be used.
  • This object is achieved by the method mentioned ⁇ he inventions that are used as blowing agents molecules of C and / or molecules of B and N, which have a spherical or tubular structure, wherein the propellant chemically or physically to these moles - is bound.
  • the spherical molecules are known at ⁇ example as so-called fullerenes. These are regular structures, for example carbon atoms.
  • a special example is the Fulleren, which is designated as , ⁇ , whose structure resembles that of a football.
  • tubular structures are carbon nanotubes (in Fol ⁇ constricting briefly as CNT called) or boron nitride nanotubes (hereinafter referred to as BNNT) known.
  • a chemical binding of the propellant can be carried out, for example, by a functionalization of these molecules.
  • the blowing agent thus obtained reacts in the presence of a reactant such as O2 in a temperature range of more than 1000 ° C. This typically releases CO2, which then acts as a propellant gas. With this example of a blowing agent, it is thus possible to process metals into foams which have a solidus temperature of more than 1000 °.
  • the propellant is bound to the molecules by a coating thereof.
  • very thin layers with thick of one or more atomic layers for example by an ALD method (ALD stands for atomic layer deposition).
  • ALD atomic layer deposition
  • the nanoparticles are kept in motion in an eddy current process.
  • To beschich ⁇ Tenden particles can be, for example CNT or BNNT.
  • Ty- pisch enough, these molecules can with titanium hydride or precious metal oxides ⁇ such.
  • iridium oxide and / or molybdenum oxide and / or platinum oxide and / or copper (I) oxide and / or magnetite and / or vanadium pentoxide are coated.
  • noble metal oxides are advantageous because they decompose due to their low affinity for oxygen more easily into the Metallkompo ⁇ component and an oxygen component which represents the drive means. This is done in tempera ⁇ tures that are interesting for the formation of metal foams.
  • iridium oxide and platinum oxide decompose at temperatures of about 1200 ° C.
  • ruthenium oxide and rhodium oxide at temperatures of about 1100 ° C.
  • molybdenum oxide likewise at 1100 ° C.
  • Oxides with even higher decomposition temperatures are magnetic with a decomposition temperature of 1580 ° C, copper (I) oxide with a decomposition temperature of 1800 ° C and vanadium pentoxide with a decomposition temperature of 1750 ° C.
  • the oxides can be suitably selected depending on the solidus temperature of the metal used for foaming, where ⁇ must be taken into account that the decomposition temperature of the selected metal oxide must be lower than the relevant solidus temperature of the metal used, by up to 120 ° C.
  • the propellant gas can also be enclosed in these molecules, ie be present as propellant gas even at room temperature. However, this is only released when the spherical molecules are destroyed. For this purpose, a heating of the same to 1500 ° C is necessary.
  • gas-loaded fullerenes can He or 2 are included and will be referred to as He @ C60 or 2 @ C60. If the gas from the interior of the fullerenes liberated ⁇ , this is by disintegration thereof as propellant gas. This means that metals with a solidus temperature of about 1600 ° C. can also be foamed with such blowing agents.
  • the composite is formed from metal particles or metal alloy particles, wherein at least part of these particles is coated with a layer of the blowing agent.
  • the blowing agent so prior to the processing ⁇ processing of the metal particles to form a component (green compact) is so kondi ⁇ tioniert that the foaming agent is already incorporated in the green body in the production of the green compact.
  • the Konzentra ⁇ tion of the blowing agent can be achieved by loading the thickness of the coating on the particles, the particle size and the proportion of coated particles compared to uncoated particles set. This is advantageous to a very accurate method for adjusting the concentration
  • the composite consists of a layer having a plurality of layers, where ⁇ are provided at successive layers of the metal or metal alloy and ⁇ from the propellant. It is particularly advantageous if layers of the blowing agent and layers of the metal alloy or of the metal alternate with one another. The concentration of blowing agent can then be adjusted by the ratio of the thickness of the metal layers to the blowing agent layers. However, the layers must be sufficient be made thin, so that a uniform distribution of the propellant gas can be carried out in the composite, so that there is a uniform distribution of the pores in the forming foam. In this way, in particular consif ⁇ CHIGE components can advantageously be very economical with layers of a metal foam coat.
  • a material having a negative coefficient of thermal expansion is additionally introduced into the composite. This may, for example, as already explained above for the blowing agent, by coating of particles or the provision of layers of this material between other layers of the metal or the blowing agent. Having a negative coefficient of thermal expansion in the metal foam are provided materials, then this coefficient of thermal expansion of the Me ⁇ tallschaums can be influenced, which decreases as a result. , ⁇ advance reduction is, however, provided that the material is constantly be ⁇ thermally that it protrudes to the formation of the metal foam not ⁇ manoeuvrable heat treatment.
  • the metal foam is particularly Before ⁇ part if the metal foam with components is associated, which have a lower thermal expansion ⁇ coefficient than the metal foam, wherein said component of the material negative with the thermal expansion coefficient is missing.
  • metal can ⁇ foaming by this measure advantageous reliably ke ⁇ ramischen glass components or components to be connected.
  • the connection between the corresponding component and the metal foam is exposed by adapting the thermal expansion coefficients of metal foam and component lower mechanical loads. In particular, be achieved by that a sealing connection between the metal foam and the component can be made more reliable and over a longer period.
  • the object is achieved by a component in which are used in the metal foam used molecules of C and / or molecules of B and N, which have a spherical ⁇ or tubular structure.
  • This mole ⁇ cules are in fact suitable in the manner described above to bind a carrier gas physically or chemically, which is now contained in the pores of the metal foam.
  • the substances of the blowing agent are in fact bound to the molecules and by a heat treatment, the carrier gas, which has ge ⁇ forms the pores of the metal foam, is released.
  • this is formed as a housing structure of a different material from the metal foam with a cavity having an opening, wherein the opening is closed by the metal foam.
  • a hermetic sealing of the cavity is advantageously possible because it forms an intimate connection between the metal foam and the housing structure in the region of the opening.
  • the metal foam is adapted in terms of its coefficient of thermal expansion in the manner indicated above to that of the housing structure, a herme ⁇ zier seal can be advantageously ensured even under thermal stress of the component over a longer period. This is particularly advantageous if the cavity is formed by a glass body, in particular a lamp.
  • FIG. 1 to 3 embodiments of the invention ⁇ parts in section, in which each left and right of a fracture line, the state before or after application of an embodiment of the method for heat treatment ⁇ treatment (formation of the metal foam) is shown schematically and
  • a component with a housing structure 11 according to FIG. 1 has a cavity 12, wherein the component may be for example a tube which is open at both ends. Through the component further extends a copper conductor 13, wherein the remainder of the cross section of the cavity 12 is to be sealed.
  • layers 14 shown in the half to the left of the break Liene 16 applied to the inner walls of the housing structure 11, which comprises alternating layers of a metal 15a and 15b of a blowing agent aufwei ⁇ sen.
  • the layers 15a, 15b are shown in FIG. 1 with a non-realistic thickness.
  • these layers can be produced, for example, by cold gas spraying, by electrochemical coating or also by an ALD process (ALD stands for Atomic Layer Depositi). on).
  • ALD Atomic Layer Depositi
  • the possi ⁇ ability to provide additional layers in the composite which consist of Mate ⁇ materials with a negative coefficient of thermal expansion.
  • Mate ⁇ materials with a negative coefficient of thermal expansion.
  • materials are for example ZrW 2 0 5, ZrV 2 0 7, Sc 2 W 3 0i 2, Y 2 W 3 0i 2, K 5 Zr (P0 4) 2 or KZR 2 (P0 4) 3 be ⁇ known.
  • the finished metal foam 18 is shown in the right half of the illustration according to FIG. 1, that is to say to the right of the fault line 16, the finished metal foam 18 is shown. This has pores 17, wherein the metal foam completely fills the cavity 12. In this case, the metal foam rests both on the copper conductor 13 and on the inner wall of the cavity 12, so that a hermeti ⁇ cal seal is formed.
  • metal particles 19 are applied to the surface, all of which have a
  • the composite 21 is formed from different particles, namely the metal particles 19 and propellant particles 22, which are mixed (see the left of the fault line 16).
  • a heat treatment generates the metal foam 18 with the pores 17 shown on the right of the break line.
  • a glass body 23 for a gas discharge lamp is is as a component that forms the cavity structure 11, provided ⁇ .
  • the cavity 12 there are two electrodes 24, which are connected by means of pinched flat conductor 25 with connection contacts 26.
  • the connection contacts 26 are guided through openings 27, so that contacting from the outside is possible.
  • These openings 27 are filled in the manner according to the invention with the metal foam 18 in order to ensure a hermetic seal of the contact bushings in the openings 27.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Sealing Material Composition (AREA)

Abstract

The invention relates to a method for generating a closed-pore metal foam. In addition, the invention relates to a component in which such a metal foam is used. The component (11), for forming the metal foam (18) having closed pores (17), before a heat treatment, is provided with a composite (21) of particles (19) of a metal, wherein these particles can have, for example, a layer (20) of a blowing agent. Alternatively (which is not shown) the metal and the blowing agent can also be arranged in a plurality of layers of a sheet, or as a mixture of particles. By means of the heat treatment, the blowing agent liberates a propellant gas, wherein it is provided according to the invention that the blowing agent consists of fullerenes or nanotubes to which the blowing agent is chemically or physically bound. Owing to the high temperature stability of the nanotubes or fullerenes, blowing agents may be generated thereby which liberate propellant gas at comparative high temperatures of above 1000°C, wherein, therefore, even metals having comparatively high solidus temperatures of above 1000°C may be processed to metal foams. A greater versatility of metal foams that can be generated results thereby as well as, consequently, a greater structural freedom.

Description

Beschreibung description
Verfahren zur Erzeugung eines geschlossenporigen Metallschaums sowie Bauteil, welches einen geschlossenporigen Me- tallschaum aufweist Method for producing a closed-cell metal foam and component, which has a closed-cell metal foam
Die Erfindung betrifft ein Verfahren zur Erzeugung eines geschlossenporigen Metallschaums, bei dem ein Verbund aus einem Metall oder einer Metalllegierung und einem Treibmittel zur Verfügung gestellt wird. Dieser Verbund wird einer Wärmebe¬ handlung unterworfen, wobei die Erwärmung des Verbundes ausreicht, damit das Treibmittel unter Ausbildung von geschlos¬ senen Poren im Verbund ein Treibgas ausbildet. Dies bedeutet, dass die geschlossenen Poren dadurch entstehen, dass das Treibgas entsteht und in den sich ausbildenden geschlossenen Poren gefangen wird. The invention relates to a method for producing a closed-cell metal foam, in which a composite of a metal or a metal alloy and a blowing agent is provided. This composite is subjected to a Wärmebe ¬ treatment, wherein the heating of the composite sufficient to cause the blowing agent forms with the formation of pores in the composite Senen CLOSED ¬ a propellant gas. This means that the closed pores are created by the propellant gas being formed and trapped in the forming closed pores.
Weiterhin betrifft die Erfindung ein Bauteil, welches zumindest teilweise aus einem geschlossenporigen Metallschaum be- steht. Furthermore, the invention relates to a component which consists at least partially of a closed-cell metal foam.
Ein Bauteil mit einer Komponente eines geschlossenporigen Me¬ tallschaums sowie ein Verfahren zu dessen Herstellung ist beispielsweise aus der US 5,151,246 bekannt. Das Bauteil kann beispielsweise aus einer Hülse bestehen, in dessen Inneren der geschlossenporige Metallschaum untergebracht ist. Um die¬ se Komponente aus einem geschlossenen Metallschaum herzustellen, werden Treibmittel verwendet, wie z. B. Metallhydride, insbesondere Titanhydrid oder Carbonate, wie z. B. Kalzium- carbonat . Aus diesen Treibmitteln und dem Metall, welches den Metallschaum bilden soll, wird ein Verbund hergestellt, der beispielsweise aus Partikeln beider Stoffe bestehen kann und durch Pressen verdichtet wird. Dieser so gebildete Grünkörper kann anschließend einer Wärmebehandlung unterzogen werden, wobei die Temperatur hoch genug sein muss, damit einerseits eine Verbindung zwischen den einzelnen Pulverteilchen des Metalls erfolgt und andererseits das Treibmittel ein Treibgas ausbildet. Um eine Verbindung zwischen den Metallpartikeln zu gewährleisten, müssen zumindest Diffusionsvorgänge zwischen den Partikeln ermöglicht werden. Hierzu muss eine genügende Erwärmung des metallischen Stoffes erfolgen. Bei den genannten Treibmitteln können Partikel aus Metallen geschäumt werden, welche eine Solidus-Temperatur von bis zu 660° haben. A component with a component of a closed-Me ¬ tallschaums and a method for its production is known for example from US 5,151,246. The component may for example consist of a sleeve, is housed in the interior of the closed-cell metal foam. To prepare the ¬ se component of a closed metal foam, blowing agents are used, such. As metal hydrides, especially titanium hydride or carbonates, such as. For example, calcium carbonate. From these propellants and the metal which is to form the metal foam, a composite is produced, which may for example consist of particles of both substances and is compacted by pressing. This green body thus formed can then be subjected to a heat treatment, wherein the temperature must be high enough so that on the one hand a connection between the individual powder particles of the metal takes place and on the other hand, the propellant forms a propellant gas. In order to ensure a connection between the metal particles, at least diffusion processes between the particles must be made possible. For this purpose, a sufficient warming of the metallic substance must take place. Particles of metals which have a solidus temperature of up to 660 ° can be foamed in the abovementioned propellants.
Metallschäume werden beispielsweise zur Abdichtung von Gehäu¬ sestrukturen verwendet. Gemäß der WO 2008/145173 AI ist dies z. B. vorteilhaft bei Gasentladungslampen, die in einem Lampenkörper montiert werden. Um eine elektrische Kontaktierung zu ermöglichen, müssen Kontakte aus dem Lampenkörper herausgeführt werden, wobei eine hermetische Abdichtung dieser Durchführungen gewährleistet sein muss, damit kein Sauerstoff in das Lampeninnere gelangt. Das Ausfüllen der Durchführung zwischen Lampenkörper und Metallelektrode kann zuverlässig mittels eines Metallschaums erfolgen. Metal foams are used for example for sealing Gehäu ¬ sestrukturen. According to WO 2008/145173 Al this is z. B. advantageous in gas discharge lamps, which are mounted in a lamp body. In order to enable electrical contact, contacts must be led out of the lamp body, whereby a hermetic seal of these bushings must be ensured so that no oxygen enters the interior of the lamp. The completion of the implementation between lamp body and metal electrode can be done reliably by means of a metal foam.
Weiterhin muss das ausgewählte Treibmittel hinsichtlich sei¬ ner thermischen Eigenschaften so ausgewählt werden, dass es zur Solidus-Temperatur des zu schäumenden Metalls (oder der zu schäumenden Metalllegierung) passt. Hierbei darf die Temperaturdifferenz zwischen der Solidus-Temperatur des Metalls und der geringeren Temperatur, bei der das Treibmittel das Treibgas freisetzt, nicht mehr als 120° C betragen. Nur so ist gewährleistet, dass sich zuverlässig ein Metallschaum bildet. Ist im Folgenden von Metallschäumen die Rede, so sind hiermit auch Schäume aus Metalllegierungen zu verstehen. Furthermore, the selected propellant must be chosen with regard to whether ¬ ner thermal properties (or the foaming metal alloy) that it fits to the solidus temperature of the foaming metal. Here, the temperature difference between the solidus temperature of the metal and the lower temperature at which the propellant releases the propellant must not exceed 120 ° C. This is the only way to ensure that a metal foam is reliably formed. If we talk about metal foams in the following, foams made of metal alloys are also to be understood here.
Die Aufgabe der Erfindung liegt darin, ein Verfahren zur Erzeugung eines geschlossenporigen Metallschaums sowie ein Bau- teil mit einem solchen geschlossenporigen Metallschaum anzugeben, bei dem Metalle mit Solidus-Temperaturen von mehr als 660 °C zum Einsatz kommen können. Diese Aufgabe wird mit dem eingangs genannten Verfahren er¬ findungsgemäß dadurch gelöst, dass als Treibmittel Moleküle aus C und/oder Moleküle aus B und N zum Einsatz kommen, die eine kugelförmige oder eine rohrförmige Struktur aufweisen, wobei das Treibgas chemisch oder physikalisch an diese Mole- küle gebunden wird. Die kugelförmigen Moleküle sind bei¬ spielsweise als sogenannte Fullerene bekannt. Hierbei handelt es sich um regelmäßige Strukturen, beispielsweise aus C- Atomen. Ein besonderes Beispiel ist das als Οβο bezeichnete Fulleren, dessen Struktur der eines Fußballs gleicht. Als rohrförmige Strukturen sind Kohlenstoff-Nanoröhrchen (im Fol¬ genden kurz als CNT bezeichnet) oder Bornitrid-Nanoröhrchen (im Folgenden als BNNT bezeichnet) bekannt. Eine chemische Bindung des Treibmittels kann beispielsweise durch eine Funk- tionalisierung dieser Moleküle erfolgen. Eine funktionelle Gruppe, die sich als Treibmittel eignet, stellt z. B. -COOMe dar. Diese Gruppe kann beispielsweise an ein C-Atom eines CNT gebunden werden, wobei Me insbesondere für Mo, Ni, Ir oder Co steht. Das so gewonnene Treibmittel reagiert bei Anwesenheit eines Reaktionspartners wie O2 in einem Temperaturbereich von mehr als 1000 °C. Dabei wird typischerweise CO2 freigesetzt, welches dann als Treibgas zur Wirkung kommt. Mit diesem Bei¬ spiel eines Treibmittels lassen sich also Metalle zu Schäumen verarbeiten, die eine Solidus-Temperatur von über 1000° aufweisen . The object of the invention is to provide a method for producing a closed-cell metal foam and a building Specify with such a closed-cell metal foam, in which metals with solidus temperatures of more than 660 ° C can be used. This object is achieved by the method mentioned ¬ he inventions that are used as blowing agents molecules of C and / or molecules of B and N, which have a spherical or tubular structure, wherein the propellant chemically or physically to these moles - is bound. The spherical molecules are known at ¬ example as so-called fullerenes. These are regular structures, for example carbon atoms. A special example is the Fulleren, which is designated as ,βο, whose structure resembles that of a football. As tubular structures are carbon nanotubes (in Fol ¬ constricting briefly as CNT called) or boron nitride nanotubes (hereinafter referred to as BNNT) known. A chemical binding of the propellant can be carried out, for example, by a functionalization of these molecules. A functional group which is suitable as a propellant, z. B. -COOMe. This group can be bound, for example, to a carbon atom of a CNT, where Me is in particular Mo, Ni, Ir or Co stands. The blowing agent thus obtained reacts in the presence of a reactant such as O2 in a temperature range of more than 1000 ° C. This typically releases CO2, which then acts as a propellant gas. With this example of a blowing agent, it is thus possible to process metals into foams which have a solidus temperature of more than 1000 °.
Es ist auch möglich, dass das Treibmittel an die Moleküle durch eine Beschichtung derselben gebunden ist. Hierbei werden sehr dünne Schichten mit dicken von einer oder mehreren Atomlagen beispielsweise durch ein ALD-Verfahren (ALD steht für Atomic Layer Deposition) aufgebracht. Dabei werden die Nanopartikel in einem Wirbelstromverfahren in Bewegung gehalten. Dieses Verfahren ist bereits bekannt. Die zu beschich¬ tenden Partikel können beispielsweise CNT oder BNNT sein. Ty- pischerweise können diese Moleküle mit Titanhydrid oder Edel¬ metalloxiden, wie z. B. Iridiumoxid und/oder Molybdänoxid und/oder Platinoxid und/oder Kupfer ( I ) -Oxid und/oder Magnetid und/oder Vanadiumpentoxid beschichtet werden. Die Verwendung von Edelmetalloxiden ist vorteilhaft, da diese aufgrund ihrer geringen Affinität zu Sauerstoff leichter in die Metallkompo¬ nente und eine Sauerstoffkomponente zerfallen, welche das Treibmittel zur Verfügung stellt. Dies geschieht bei Tempera¬ turen, die für die Bildung von Metallschäumen interessant sind. So zerfallen Iridiumoxid und Platinoxid beispielsweise bei Temperaturen um 1200 °C, Rutheniumoxid und Rhodiumoxid bei Temperaturen von ungefähr 1100 °C und Molybdänoxid ebenfalls bei 1100 °C. Oxide mit noch höheren Zerfallstemperatu- ren sind Magnetid mit einer Zerfallstemperatur von 1580 °C, Kupfer ( I ) -Oxid mit einer Zerfallstemperatur von 1800 °C und Vanadiumpentoxid mit einer Zerfallstemperatur von 1750 °C. Damit können die Oxide je nach Solidustemperatur des zum Schäumen verwendeten Metalls geeignet ausgewählt werden, wo¬ bei berücksichtigt werden muss, dass die Zerfallstemperatur des gewählten Metalloxids geringer ausfallen muss, als die betreffende Solidustemperatur des verwendeten Metalls, und zwar um bis zu 120 °C. It is also possible that the propellant is bound to the molecules by a coating thereof. Here are very thin layers with thick of one or more atomic layers, for example by an ALD method (ALD stands for atomic layer deposition). The nanoparticles are kept in motion in an eddy current process. This method is already known. To beschich ¬ Tenden particles can be, for example CNT or BNNT. Ty- pisch enough, these molecules can with titanium hydride or precious metal oxides ¬ such. As iridium oxide and / or molybdenum oxide and / or platinum oxide and / or copper (I) oxide and / or magnetite and / or vanadium pentoxide are coated. The use of noble metal oxides is advantageous because they decompose due to their low affinity for oxygen more easily into the Metallkompo ¬ component and an oxygen component which represents the drive means. This is done in tempera ¬ tures that are interesting for the formation of metal foams. For example, iridium oxide and platinum oxide decompose at temperatures of about 1200 ° C., ruthenium oxide and rhodium oxide at temperatures of about 1100 ° C. and molybdenum oxide likewise at 1100 ° C. Oxides with even higher decomposition temperatures are magnetic with a decomposition temperature of 1580 ° C, copper (I) oxide with a decomposition temperature of 1800 ° C and vanadium pentoxide with a decomposition temperature of 1750 ° C. Thus, the oxides can be suitably selected depending on the solidus temperature of the metal used for foaming, where ¬ must be taken into account that the decomposition temperature of the selected metal oxide must be lower than the relevant solidus temperature of the metal used, by up to 120 ° C.
Werden als Moleküle kugelförmige Moleküle verwendet, kann das Treibgas gemäß einer vorteilhaften Ausgestaltung der Erfin- dung auch in diese Moleküle eingeschlossen sein, also schon bei Raumtemperatur als Treibgas vorliegen. Dieses wird dann allerdings erst freigesetzt, wenn die kugelförmigen Moleküle zerstört werden. Hierzu ist eine Erwärmung derselben auf 1500°C notwendig. Gasbeladene Fullerene können beispielsweise He oder 2 enthalten und werden dann als He@C60 oder 2@C60 bezeichnet. Wird das Gas aus dem Inneren der Fullerene frei¬ gesetzt, so steht dies nach Zerfall derselben als Treibgas zur Verfügung. Dies bedeutet, dass mit derartigen Treibmit- teln auch Metalle mit einer Solidus-Temperatur von ca. 1600 °C geschäumt werden können. If spherical molecules are used as molecules, according to an advantageous embodiment of the invention, the propellant gas can also be enclosed in these molecules, ie be present as propellant gas even at room temperature. However, this is only released when the spherical molecules are destroyed. For this purpose, a heating of the same to 1500 ° C is necessary. For example, gas-loaded fullerenes can He or 2 are included and will be referred to as He @ C60 or 2 @ C60. If the gas from the interior of the fullerenes liberated ¬, this is by disintegration thereof as propellant gas. This means that metals with a solidus temperature of about 1600 ° C. can also be foamed with such blowing agents.
Gemäß einer anderen Ausgestaltung der Erfindung ist vorgesehen, dass der Verbund aus Metallpartikeln oder Metalllegie- rungspartikeln gebildet ist, wobei zumindest ein Teil dieser Partikel mit einer Schicht des Treibmittels beschichtet ist. Hierbei wird das Treibmittel also bereits vor der Verarbei¬ tung der Metallpartikel zu einem Bauteil (Grünling) so kondi¬ tioniert, dass bei der Herstellung des Grünlings das Treib- mittel bereits in den Grünling eingebaut wird. Die Konzentra¬ tion des Treibmittels lässt sich durch die Dicke der Be- schichtung auf den Partikeln, die Partikelgröße bzw. den Anteil von beschichteten Partikeln im Vergleich zu unbeschichteten Partikeln einstellen. Hierdurch steht vorteilhaft ein sehr genaues Verfahren zur Einstellung der Konzentration anAccording to another embodiment of the invention, it is provided that the composite is formed from metal particles or metal alloy particles, wherein at least part of these particles is coated with a layer of the blowing agent. In this case, the blowing agent so prior to the processing ¬ processing of the metal particles to form a component (green compact) is so kondi ¬ tioniert that the foaming agent is already incorporated in the green body in the production of the green compact. The Konzentra ¬ tion of the blowing agent can be achieved by loading the thickness of the coating on the particles, the particle size and the proportion of coated particles compared to uncoated particles set. This is advantageous to a very accurate method for adjusting the concentration
Treibmittel zur Verfügung. Die Konzentration des Treibmittels entscheidet anschließend über die Größe und die Konzentration an Poren in dem Metallschaum und somit auch über dessen Dichte . Propellant available. The concentration of propellant then decides on the size and concentration of pores in the metal foam and thus also on its density.
Eine andere Ausgestaltung der Erfindung wird erhalten, wenn der Verbund aus einer Schicht mit mehreren Lagen besteht, wo¬ bei aufeinanderfolgende Lagen aus dem Metall oder der Metall¬ legierung und aus dem Treibmittel vorgesehen sind. Besonders vorteilhaft ist es, wenn Lagen des Treibmittels und Lagen der Metalllegierung oder des Metalls einander abwechseln. Die Konzentration an Treibmittel kann dann durch das Verhältnis der Dicke der Metallschichten zu den Treibmittelschichten eingestellt werden. Allerdings müssen die Lagen hinreichend dünn ausgeführt sein, damit eine gleichmäßige Verteilung des Treibgases in dem Verbund erfolgen kann, so dass auch eine gleichmäßige Verteilung der Poren in dem sich ausbildenden Schaum erfolgt. Hierdurch lassen sich insbesondere größerflä¬ chige Bauteile vorteilhaft sehr wirtschaftlich mit Schichten eines Metallschaums überziehen. Another embodiment of the invention is obtained when the composite consists of a layer having a plurality of layers, where ¬ are provided at successive layers of the metal or metal alloy and ¬ from the propellant. It is particularly advantageous if layers of the blowing agent and layers of the metal alloy or of the metal alternate with one another. The concentration of blowing agent can then be adjusted by the ratio of the thickness of the metal layers to the blowing agent layers. However, the layers must be sufficient be made thin, so that a uniform distribution of the propellant gas can be carried out in the composite, so that there is a uniform distribution of the pores in the forming foam. In this way, in particular größerflä ¬ CHIGE components can advantageously be very economical with layers of a metal foam coat.
Besonders vorteilhaft ist es, wenn in den Verbund zusätzlich ein Material mit einem negativen thermischen Ausdehnungskoeffizienten eingebracht wird. Dies kann beispielsweise, wie oben für das Treibmittel bereits erläutert, durch Beschichten von Partikeln oder das Vorsehen von Lagen dieses Materials zwischen anderen Lagen des Metalls bzw. des Treibmittels erfolgen. Werden Materialien mit einem negativen thermischen Ausdehnungskoeffizienten in dem Metallschaum vorgesehen, so kann hierdurch der thermische Ausdehnungskoeffizient des Me¬ tallschaums beeinflusst werden, der hierdurch sinkt. Voraus¬ setzung ist allerdings, dass das Material thermisch so be¬ ständig ist, dass es die zur Bildung des Metallschaumes not¬ wendige Wärmebehandlung übersteht. It is particularly advantageous if a material having a negative coefficient of thermal expansion is additionally introduced into the composite. This may, for example, as already explained above for the blowing agent, by coating of particles or the provision of layers of this material between other layers of the metal or the blowing agent. Having a negative coefficient of thermal expansion in the metal foam are provided materials, then this coefficient of thermal expansion of the Me ¬ tallschaums can be influenced, which decreases as a result. , ¬ advance reduction is, however, provided that the material is constantly be ¬ thermally that it protrudes to the formation of the metal foam not ¬ manoeuvrable heat treatment.
Der durch das Material verringerte thermische Ausdehnungsko¬ effizient des Metallschaumes ist insbesondere dann von Vor¬ teil, wenn der Metallschaum mit Bauteilen in Verbindung gebracht wird, welche einen geringeren thermischen Ausdehnungs¬ koeffizienten aufweisen als der Metallschaum, bei dem die Komponente des Materials mit dem negativen thermischen Aus¬ dehnungskoeffizienten fehlt. Beispielsweise können Metall¬ schäume durch diese Maßnahme vorteilhaft zuverlässig mit ke¬ ramischen Bauteilen oder gläsernen Bauteilen verbunden werden. Die Verbindung zwischen dem entsprechenden Bauteil und dem Metallschaum ist durch Anpassung der thermischen Ausdehnungskoeffizienten von Metallschaum und Bauteil geringeren mechanischen Belastungen ausgesetzt. Insbesondere kann hier- durch erreicht werden, dass eine dichtende Verbindung zwischen dem Metallschaum und dem Bauteil zuverlässiger und über einen längeren Zeitraum erfolgen kann. The reduced by the material thermal Ausdehnungsko ¬ efficiently the metal foam is particularly Before ¬ part if the metal foam with components is associated, which have a lower thermal expansion ¬ coefficient than the metal foam, wherein said component of the material negative with the thermal expansion coefficient is missing. For example, metal can ¬ foaming by this measure advantageous reliably ke ¬ ramischen glass components or components to be connected. The connection between the corresponding component and the metal foam is exposed by adapting the thermal expansion coefficients of metal foam and component lower mechanical loads. In particular, be achieved by that a sealing connection between the metal foam and the component can be made more reliable and over a longer period.
Weiterhin wird die Aufgabe durch ein Bauteil gelöst, bei dem in dem zum Einsatz kommenden Metallschaum Moleküle aus C und/oder Moleküle aus B und N enthalten sind, die eine kugel¬ förmige oder eine rohrförmige Struktur aufweisen. Diese Mole¬ küle sind nämlich in der oben angegebenen Weise geeignet, ein Trägergas physikalisch oder chemisch zu binden, welches nun in den Poren des Metallschaums enthalten ist. In der oben angegebenen Weise werden nämlich die Substanzen des Treibmittels an die Moleküle gebunden und durch eine Wärmebehandlung wird das Trägergas, welches die Poren des Metallschaums ge¬ bildet hat, freigesetzt. Furthermore, the object is achieved by a component in which are used in the metal foam used molecules of C and / or molecules of B and N, which have a spherical ¬ or tubular structure. This mole ¬ cules are in fact suitable in the manner described above to bind a carrier gas physically or chemically, which is now contained in the pores of the metal foam. In the above example, the substances of the blowing agent are in fact bound to the molecules and by a heat treatment, the carrier gas, which has ge ¬ forms the pores of the metal foam, is released.
Gemäß einer vorteilhaften Ausgestaltung des Bauteils ist vorgesehen, dass dieses als Gehäusestruktur aus einem vom Metallschaum verschiedenen Material mit einem eine Öffnung aufweisenden Hohlraum ausgebildet ist, wobei die Öffnung durch den Metallschaum verschlossen ist. Hierbei ist vorteilhaft eine hermetische Versiegelung des Hohlraums möglich, da sie zwischen dem Metallschaum und der Gehäusestruktur im Bereich der Öffnung eine innige Verbindung ausbildet. Insbesondere, wenn der Metallschaum hinsichtlich seines thermischen Ausdehnungskoeffizienten in der oben angegebenen Weise an denjenigen der Gehäusestruktur angepasst ist, lässt sich eine herme¬ tische Versiegelung auch bei thermischer Belastung des Bauteils über einen längeren Zeitraum vorteilhaft sicherstellen. Dies ist besonders vorteilhaft, wenn der Hohlraum durch einen Glaskörper, insbesondere einer Lampe, ausgebildet ist. According to an advantageous embodiment of the component is provided that this is formed as a housing structure of a different material from the metal foam with a cavity having an opening, wherein the opening is closed by the metal foam. In this case, a hermetic sealing of the cavity is advantageously possible because it forms an intimate connection between the metal foam and the housing structure in the region of the opening. In particular, if the metal foam is adapted in terms of its coefficient of thermal expansion in the manner indicated above to that of the housing structure, a herme ¬ tische seal can be advantageously ensured even under thermal stress of the component over a longer period. This is particularly advantageous if the cavity is formed by a glass body, in particular a lamp.
Weitere Einzelheiten der Erfindung werden nachfolgend anhand der Zeichnung beschrieben. Gleiche oder sich entsprechende Zeichnungselemente sind in den einzelnen Figuren jeweils mit dem gleichen Bezugszeichen versehen und werden nur insoweit mehrfach erläutert, wie sich Unterschiede zwischen den einzelnen Figuren ergeben. Es zeigen: Further details of the invention are described below with reference to the drawing. Same or appropriate Drawing elements are each provided with the same reference numerals in the individual figures and will only be explained several times to the extent that differences arise between the individual figures. Show it:
Figur 1 bis 3 Ausführungsbeispiele für erfindungsgemäße Bau¬ teile im Schnitt, bei denen jeweils links und rechts einer Bruchlinie der Zustand vor bzw. nach Anwendung eines Ausführungsbeispiels des erfindungsgemäßen Verfahrens zur Wärmebehand¬ lung (Bildung des Metallschaumes) schematisch dargestellt ist und Figure 1 to 3 embodiments of the invention ¬ parts in section, in which each left and right of a fracture line, the state before or after application of an embodiment of the method for heat treatment ¬ treatment (formation of the metal foam) is shown schematically and
Figur 4 einen Lampenkörper mit versiegelter Durchfüh- rungen für die Kontaktierung, wobei die Versiegelung durch ein Ausführungsbeispiel des erfindungsgemäßen Metallschaums ausgebildet ist . Ein Bauteil mit einer Gehäusestruktur 11 gemäß Figur 1 weist einen Hohlraum 12 auf, wobei das Bauteil beispielsweise ein Rohr sein kann, welches an beiden Enden offen ist. Durch das Bauteil verläuft weiterhin ein Kupferleiter 13, wobei der Rest des Querschnitts des Hohlraums 12 abgedichtet werden soll. Zu diesem Zweck werden Schichten 14 (dargestellt in der Hälfte links von der Bruchliene 16) auf die Innenwände der Gehäusestruktur 11 aufgebracht, die sich einander abwechselnde Lagen 15a eines Metalls und 15b eines Treibmittels aufwei¬ sen. Die Lagen 15a, 15b sind in Figur 1 mit einer nicht rea- listischen Dicke dargestellt. Es können selbstverständlich dünnere Lagen und hiervon eine wesentlich höhere Anzahl vorgesehen werden. Diese Lagen können beispielsweise durch Kaltgasspritzen, durch elektrochemisches Beschichten oder auch durch ein ALD-Verfahren (ALD steht für Atomic Layer Depositi- on) aufgebracht werden. Nicht dargestellt ist die Möglich¬ keit, weitere Lagen in dem Verbund vorzusehen, die aus Mate¬ rialien mit einem negativen thermischen Ausdehnungskoeffizienten bestehen. Als solche Materialien sind beispielsweise ZrW205, ZrV207, Sc2W30i2, Y2W30i2, K5Zr(P04)2 oder KzR2(P04)3 be¬ kannt . 4 shows a lamp body with sealed passages for contacting, the seal being formed by an embodiment of the metal foam according to the invention. A component with a housing structure 11 according to FIG. 1 has a cavity 12, wherein the component may be for example a tube which is open at both ends. Through the component further extends a copper conductor 13, wherein the remainder of the cross section of the cavity 12 is to be sealed. To this end layers 14 (shown in the half to the left of the break Liene 16) applied to the inner walls of the housing structure 11, which comprises alternating layers of a metal 15a and 15b of a blowing agent aufwei ¬ sen. The layers 15a, 15b are shown in FIG. 1 with a non-realistic thickness. Of course, thinner layers and a much larger number of these can be provided. These layers can be produced, for example, by cold gas spraying, by electrochemical coating or also by an ALD process (ALD stands for Atomic Layer Depositi). on). Not shown is the possi ¬ ability to provide additional layers in the composite, which consist of Mate ¬ materials with a negative coefficient of thermal expansion. As such materials are for example ZrW 2 0 5, ZrV 2 0 7, Sc 2 W 3 0i 2, Y 2 W 3 0i 2, K 5 Zr (P0 4) 2 or KZR 2 (P0 4) 3 be ¬ known.
In der rechten Hälfte der Darstellung gemäß Figur 1, also rechts der Bruchlinie 16, ist der fertig gestellte Metall- schäum 18 dargestellt. Dieser weist Poren 17 auf, wobei der Metallschaum den Hohlraum 12 vollständig ausfüllt. Dabei liegt der Metallschaum sowohl an dem Kupferleiter 13 als auch an der Innenwand des Hohlraums 12 an, so dass eine hermeti¬ sche Versiegelung ausgebildet ist. In the right half of the illustration according to FIG. 1, that is to say to the right of the fault line 16, the finished metal foam 18 is shown. This has pores 17, wherein the metal foam completely fills the cavity 12. In this case, the metal foam rests both on the copper conductor 13 and on the inner wall of the cavity 12, so that a hermeti ¬ cal seal is formed.
Wie groß die Konzentration an Poren 17 im Metallschaum 18 ist, hängt von der Konzentration des Treibmittels ab. In Fi¬ gur 1 (sowie auch in den weiteren Figuren) sind die Poren lediglich exemplarisch dargestellt. Die Konzentration der Poren kann in der Realität sehr viel größer sein, so dass zwischen diesen lediglich verhältnismäßig dünnwandige metallische Strukturen ausgebildet sind. Hierdurch lässt sich insbesonde¬ re eine Dichtungsstruktur mit einem geringen spezifischen Gewicht erzielen. How large the concentration of pores 17 in the metal foam 18 depends on the concentration of the blowing agent. In Fi gure 1 (as well as in the other figures), the pores are shown only by way of example. The concentration of the pores can be much greater in reality, so that only relatively thin-walled metallic structures are formed between them. In this way insbesonde ¬ re lets achieve a sealing structure with a low specific weight.
Bei der Gehäusestruktur 11 gemäß Figur 2 sind auf die Oberfläche Metallpartikel 19 aufgebracht, welche alle eine In the case of the housing structure 11 according to FIG. 2, metal particles 19 are applied to the surface, all of which have a
Schicht 20 aus dem Treibmittel aufweisen. Nicht dargestellt ist eine Variante, nach der lediglich ein Teil der Partikel 19 eine solche Schicht aufweisen, wodurch ein Gemisch aus be¬ schichteten und unbeschichteten Partikeln 19 entstehen würde. Nach einer Wärmebehandlung entsprechend dem erfindungsgemäßen Verfahren bildet sich durch Entstehung eines Treibgases aus der Schicht 20 des Treibmittels ein geschlossenporiger Me- tallschaum 18 aus, der rechts der Bruchlinie 16 dargestellt ist . Have layer 20 of the propellant. Not shown is a variant according to which only a part of the particles 19 have such a layer, whereby a mixture of coated ¬ and uncoated particles 19 would arise. After a heat treatment in accordance with the method according to the invention, the formation of a propellant gas from the layer 20 of the propellant forms a closed-cell membrane. tallschaum 18, which is shown on the right of the fault line 16.
Gemäß Figur 3 wird der Verbund 21 aus unterschiedlichen Par- tikeln gebildet, nämlich den Metallpartikeln 19 und Treibmittelpartikeln 22, welche gemischt vorliegen (siehe links der Bruchlinie 16) . Auch hier erzeugt eine Wärmebehandlung den rechts der Bruchlinie dargestellten Metallschaum 18 mit den Poren 17. According to FIG. 3, the composite 21 is formed from different particles, namely the metal particles 19 and propellant particles 22, which are mixed (see the left of the fault line 16). Here, too, a heat treatment generates the metal foam 18 with the pores 17 shown on the right of the break line.
Gemäß Figur 4 ist als Bauteil, welches die Hohlraumstruktur 11 bildet, ein Glaskörper 23 für eine Gasentladungslampe dar¬ gestellt. In dem Hohlraum 12 befinden sich zwei Elektroden 24, die über in Quetschungen befindliche Flachleiter 25 mit Anschlusskontakten 26 verbunden sind. Die Anschlusskontakte 26 werden durch Öffnungen 27 geführt, damit eine Kontaktie- rung von außen möglich ist. Diese Öffnungen 27 sind in der erfindungsgemäßen Weise mit dem Metallschaum 18 gefüllt, um eine hermetische Versiegelung der Kontaktdurchführungen in den Öffnungen 27 zu gewährleisten. According to Figure 4, a glass body 23 for a gas discharge lamp is is as a component that forms the cavity structure 11, provided ¬. In the cavity 12 there are two electrodes 24, which are connected by means of pinched flat conductor 25 with connection contacts 26. The connection contacts 26 are guided through openings 27, so that contacting from the outside is possible. These openings 27 are filled in the manner according to the invention with the metal foam 18 in order to ensure a hermetic seal of the contact bushings in the openings 27.

Claims

Patentansprüche claims
1. Verfahren zur Erzeugung eines geschlossenporigen Metallschaumes (18), bei dem 1. A method for producing a closed-cell metal foam (18), in which
· ein Verbund (21) aus einem Metall oder einer Metallle¬ gierung und einem Treibmittel zur Verfügung gestellt wird und · A composite (21) made of a metal or a Metallle ¬ Government and a blowing agent is provided and
• der Verbund (21) einer Wärmebehandlung unterworfen wird, wobei die Erwärmung des Verbundes ausreicht, damit das Treibmittel unter Ausbildung von geschlossenen Poren • the composite (21) is subjected to a heat treatment, wherein the heating of the composite is sufficient to allow the blowing agent to form closed pores
(17) im Verbund (21) ein Treibgas ausbildet, (17) in the composite (21) forms a propellant gas,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass als Treibmittel Moleküle aus C und/oder Moleküle aus B und N zu Einsatz kommen, die eine kugelförmige oder eine rohrförmige Struktur aufweisen, wobei das Treibgas chemisch oder physikalisch an diese Moleküle gebunden wird. that are used as blowing agents molecules of C and / or molecules of B and N, which have a spherical or tubular structure, wherein the propellant is chemically or physically bound to these molecules.
2. Verfahren nach Anspruch 1, 2. The method according to claim 1,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass das Treibmittel an die Moleküle durch eine Funktionali¬ sierung derselben oder Beschichtung derselben gebunden wird. that the blowing agent to the molecules by a functionali ¬ tion of the same or coating thereof is bound.
3. Verfahren nach Anspruch 2, 3. The method according to claim 2,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass die Funktionalisierung der Moleküle durch Anbindung der funktionellen Gruppe -COOMe erfolgt, wobei Me insbesondere Mo, Ni, Ir oder Co ist. in that the functionalization of the molecules takes place by attachment of the functional group -COOMe, where Me is in particular Mo, Ni, Ir or Co.
4. Verfahren nach einem der vorangehenden Ansprüche, 4. The method according to any one of the preceding claims,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass als Moleküle kugelförmige Moleküle verwendet werden, in die das Treibgas eingeschlossen ist. that spherical molecules are used as molecules, in which the propellant is trapped.
5. Verfahren nach Anspruch 4, 5. The method according to claim 4,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass als Treibgas Helium und/oder Stickstoff in die Moleküle eingeschlossen ist. that as propellant helium and / or nitrogen is included in the molecules.
6. Verfahren nach einem der vorangehenden Ansprüche, 6. The method according to any one of the preceding claims,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass der Verbund (21) aus Metallpartikeln (19) oder Metallle- gierungspartikeln gebildet ist, wobei zumindest ein Teil die¬ ser Partikel mit einer Schicht (20) des Treibmittels be¬ schichtet ist. that the composite (21) of metal particles (19) or is formed Metallle- gierungspartikeln, wherein at least a portion of the particles is ser ¬ ¬ be overcoated with a layer (20) of the propellant.
7. Verfahren nach einem der vorangehenden Ansprüche, 7. The method according to any one of the preceding claims,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass der Verbund aus einer Schicht (14) mit mehreren Lagen (15a, 15b) besteht, wobei (15a, 15b) aufeinander folgende La¬ gen aus dem Metall oder der Metalllegierung und aus dem that the composite consists of a layer (14) having a plurality of layers (15a, 15b), there being (15a, 15b) consecutive La ¬ gene from the metal or metal alloy and from the
Treibmittel vorgesehen sind. Propellants are provided.
8. Verfahren nach einem der vorangehenden Ansprüche, 8. The method according to any one of the preceding claims,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass in den Verbund (21) zusätzlich ein Material mit einem negativen thermischen Ausdehnungskoeffizienten eingebracht wird. that in the composite (21) in addition a material with a negative coefficient of thermal expansion is introduced.
9. Bauteil, welches zumindest teilweise aus einem geschlos¬ senporigen Metallschaum (18) besteht, 9. The component, which consists at least partially of a CLOSED ¬ senporigen metal foam (18)
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass in dem Metallschaum (18) Moleküle aus C und/oder Molekü¬ le aus B und N enthalten sind, die eine kugelförmige oder ei¬ ne rohrförmige Struktur aufweisen. that in the metal foam (18) molecules of C and / or molecules ¬ le of B and N are included, which have a spherical or ei ¬ ne tubular structure.
10. Bauteil nach Anspruch 9, 10. Component according to claim 9,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass dieses als Gehäusestruktur (11) aus einem vom Metall- schäum (18) verschiedenen Material mit einem eine Öffnungthat this as a housing structure (11) of a material different from the metal foam (18) with a one opening
(27) aufweisenden Hohlraum (12) ausgebildet ist, welche durch den Metallschaum (18) verschlossen ist. (27) having cavity (12) is formed, which is closed by the metal foam (18).
11. Bauteil nach Anspruch 10, 11. Component according to claim 10,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass der Hohlraum (12) durch einen Glaskörper (23) insbesondere einer Lampe gebildet ist. the cavity (12) is formed by a glass body (23), in particular a lamp.
12. Bauteil nach einem der Ansprüche 10 oder 11, 12. Component according to one of claims 10 or 11,
d a d u r c h g e k e n n z e i c h n e t , characterized ,
dass zusätzlich ein Material mit einem negativen thermischen Ausdehnungskoeffizienten in dem Metallschaum vorhanden ist, dessen Anteil so gewählt ist, dass der Metallschaum (18) zu¬ mindest im wesentlichen den gleichen Ausdehnungskoeffizienten wie die Gehäusestruktur (11) im Bereich der Öffnung (27) aufweist. that in addition a material with a negative coefficient of thermal expansion in the metal foam is present, whose proportion is selected so that the metal foam (18) ¬ at least substantially the same expansion coefficient as the housing structure (11) in the region of the opening (27).
EP11722373.5A 2010-05-31 2011-05-19 Method for generating a closed-pore metal foam and component which has a closed-pore metal foam Withdrawn EP2576103A1 (en)

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PCT/EP2011/058178 WO2011151193A1 (en) 2010-05-31 2011-05-19 Method for generating a closed-pore metal foam and component which has a closed-pore metal foam

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DE102010022598B3 (en) 2011-12-01
US8871357B2 (en) 2014-10-28

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