EP1031393B1 - Preparation of metal foams - Google Patents
Preparation of metal foams Download PDFInfo
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- EP1031393B1 EP1031393B1 EP00102816A EP00102816A EP1031393B1 EP 1031393 B1 EP1031393 B1 EP 1031393B1 EP 00102816 A EP00102816 A EP 00102816A EP 00102816 A EP00102816 A EP 00102816A EP 1031393 B1 EP1031393 B1 EP 1031393B1
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- Prior art keywords
- metal
- blowing agent
- temperature
- melting
- mixture
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- 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
- B22F3/1125—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers involving a foaming process
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- 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
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
Definitions
- the invention relates to a method for producing Metal foams.
- DE 197 44 300 A deals with the manufacture and use of porous light metal parts or light metal alloy parts, being made from a powder mixture (Light metal or Al alloy and blowing agent) pressed Body in a heated closed vessel with inlet and Outlet opening at temperatures above the decomposition temperature of the blowing agent and / or melting temperature of the metal or the alloy are heated.
- JP 03017236 A describes a method for production metallic article with cavities by placing gases in a Metal melt dissolves and then the foaming process by sudden Reduces pressure. Cooling of the melt stabilized the foam thus obtained.
- WO 92/21457 teaches the production of Al foam or Al alloy foam by blowing gas under the surface of a molten metal, whereby abrasives, such as. B. SiC, ZrO 2 , etc., serve as stabilizers.
- Foam aluminum becomes molten aluminum after infiltration into a porous filler by removing it obtained from the solidified metal (Zhuzao Bianjibu (1997) (2) 1-4; ZHUZET, ISSN: 1001-4977).
- the processes involving precompacting propellants Provide green bodies that are complex and costly not suitable for the production of bulk goods. Besides, is common to these processes is that the desired temperature difference between the melting point of the metal to be foamed and the decomposition temperature of the blowing agent used if possible should be low, otherwise it is already during compacting or later disruptive blowing agent decomposition in the melting phase takes place.
- the infiltration technology should also be assessed from this perspective, in which one painstakingly removes the porous filler from the foam matrix must remove.
- the dissolving or blowing in of propellant gases in molten metal is not suitable for the production of near-net shape workpieces, because a System consisting of the melt with occluded gas bubbles, is not sufficiently stable in time to be used in shaping tools to be processed.
- the above object is thus achieved in a first embodiment by a method for producing metal foams, wherein one or more metal powders, optionally applied with more or less lumpy metallic or non-metallic, e.g. B. mineral aggregates, mixed with a gas-releasing blowing agent, the mixture in an open or closed form, if necessary preheated to a temperature below the decomposition temperature of the blowing agent, the mixture is then heated to a temperature above the melting temperature of the low-melting metal, that the temperature difference between the equilibrium decomposition temperature of the blowing agent and the melting temperature of the metal or the melting temperature of the lowest-melting metal in a metal mixture is bridged in a period of time that is shorter than the time required to reach the equilibrium state in the blowing agent / propellant system at this temperature is required and cools the metal foam obtained to a temperature below the melting point of the lowest-melting metal.
- one or more metal powders optionally applied with more or less lumpy metallic or non-metallic, e.g. B. mineral aggregates, mixed
- the method according to the invention dispenses with methods which are described in the metal matrix to be foamed for the construction of a Propellant pressure counteracting mechanical resistance are responsible.
- Essential to the present invention is, however, that the temperature difference between the equilibrium decomposition temperature of the blowing agent and the melting temperature of the metal or the melting temperature of the lowest melting point Metal in a metal mixture in one Time span that is shorter than the time that is to achieve equilibrium in the propellant // propellant system at this temperature is required.
- the rapid reaching of the melting temperature of the lowest melting Metal in a metal mixture to be foamed advantageously allows the use of end matrix compatible Components (unmelted metal particles) than that Nucleation promoting the uniformity of the metal foam.
- reaction mass is heated quickly induction heating or bombardment with laser radiation.
- reaction heat of a fast, strongly exothermic Process e.g. aluminothermic reduction
- Magnesium hydride used as a gas-releasing blowing agent the is commercially available.
- metal hydrides for example titanium hydride
- carbonates for example calcium carbonate, potassium carbonate, Sodium carbonate, sodium bicarbonate, hydrates, for example Aluminum sulfate hydrate, alum, aluminum hydroxide or easily evaporating substances, for example mercury compounds or powdered organic substances used become.
- the gas-releasing Blowing agent contains the same metal ions as for the melting metal are provided.
- Blowing agent is usually very low. So that's enough Blowing agent proportions in the order of several tenths Weight percent usually from. As particularly cheap in For the purposes of the present invention, amounts of blowing agent have increased from 0.1 to 10% by weight, in particular 0.2 to 5% by weight on metal powder.
- steel with a melting point of 1500 ° C. to 1600 ° C. can be foamed using magnesium hydride ( decomposition ⁇ 280 ° C.) as a blowing agent if a small amount of MgH 2 is added to a powdered THERMIT® mixture and then the ignition of the reaction mixture initiates the aluminothermic reduction of iron oxide to iron.
- magnesium hydride decomposition ⁇ 280 ° C.
- the one obtained after cooling and sawed in the longitudinal direction Regulus according to FIG. 1 contains hydride decomposition Gas pores in metallic iron.
- this embodiment of the invention opens that wide field of "reactive foaming" of metals, with a exothermic process (e.g. a reduction) temporally and spatially to the foaming process (blowing agent decomposition and formation of the molten metal) is coupled.
- a exothermic process e.g. a reduction
- the mechanical dispensable according to the inventive method Pretreatment of the foam-forming mixture leaves almost Any shape for the foamed semi-finished products and prepares the way to mass production.
- Another embodiment of the present invention relates hence a foam-shaped semi-finished metal product that is used of the method according to the invention is available.
- the quality of the metal foam obtained using the new process depends, for example on the cooling rate of the metal mass.
- Fig. 1 shows the longitudinal profile of the porous steel body.
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- Mechanical Engineering (AREA)
- Powder Metallurgy (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
Description
Gegenstand der Erfindung ist ein Verfahren zur Herstellung von Metallschäumen.The invention relates to a method for producing Metal foams.
Der Stand der Technik zur Herstellung von Metallschäumen umfaßt
im wesentlichen fünf prinzipielle Vorgehensweisen:
ad 1) Die DE 197 44 300 A beschäftigt sich mit der Herstellung und Verwendung von porösen Leichtmetall-Teilen bzw. Leichtmetall-Legierungsteilen, wobei die aus einer Pulvermischung (Leichtmetall- bzw. Al-Legierung und Treibmittel) gepreßten Körper in einem beheizbaren geschlossenen Gefäß mit Einlaß- und Austrittsöffnung auf Temperaturen oberhalb der Zersetzungstemperatur des Treibmittels und/oder Schmelztemperatur des Metalls bzw. der Legierung erhitzt werden.ad 1) DE 197 44 300 A deals with the manufacture and use of porous light metal parts or light metal alloy parts, being made from a powder mixture (Light metal or Al alloy and blowing agent) pressed Body in a heated closed vessel with inlet and Outlet opening at temperatures above the decomposition temperature of the blowing agent and / or melting temperature of the metal or the alloy are heated.
ad 2) Die JP 03017236 A beschreibt ein Verfahren zur Erzeugung metallischer Artikel mit Hohlräumen, indem man Gase in einer Metallschmelze löst und den Aufschäumvorgang dann durch plötzliche Druckverringerung einleitet. Abkühlen der Schmelze stabilisiert den so erhaltenen Schaum.ad 2) JP 03017236 A describes a method for production metallic article with cavities by placing gases in a Metal melt dissolves and then the foaming process by sudden Reduces pressure. Cooling of the melt stabilized the foam thus obtained.
Die WO 92/21457 lehrt die Herstellung von Al-Schaum bzw. Al-Legierungsschaum durch das Einblasen von Gas unter die Oberfläche eines geschmolzenen Metalls, wobei Abrasivstoffe, wie z. B. SiC, ZrO2 usw., als Stabilisatoren dienen.WO 92/21457 teaches the production of Al foam or Al alloy foam by blowing gas under the surface of a molten metal, whereby abrasives, such as. B. SiC, ZrO 2 , etc., serve as stabilizers.
ad 3) Der Lehre der JP 09241780 A folgend, werden metallische Schäume unter kontrollierter Freisetzung von Treibgasen gewonnen, indem die Metalle zunächst bei Temperaturen unterhalb der Zersetzungstemperatur des verwendeten Treibmittels geschmolzen werden. Durch nachfolgendes Dispergieren des Treibmittels im geschmolzenen Metall und Erhitzen der Matrix über die dann zur Freisetzung von Treibgasen benötigte Temperatur etabliert sich ein Metallschaum.ad 3) Following the teaching of JP 09241780 A, metallic Foams obtained with controlled release of propellant gases, by the metals initially at temperatures below the Decomposition temperature of the blowing agent used melted become. By subsequently dispersing the blowing agent in the molten metal and then heating the matrix over to The release of propellant gases required temperature is established a metal foam.
ad 4) Die Herstellung ultraleichter Ti-6Al-4V-Hohlkugelschäume beruht auf der bei Temperaturen ≥ 1000 °C erfolgenden Sinterung metallischer Hohlkugeln, die aus der thermischen Zersetzung hydrierter Ti-6Al-4V-Hohlkugeln bei 600 °C hervorgehen (Synth./Process. Lightweight Met. Mater. II, Proc. Symp. 2nd (1997), 289-300).ad 4) The production of ultra-light Ti-6Al-4V hollow spherical foams is based on the sintering of hollow metallic spheres at temperatures ≥ 1000 ° C, which results from thermal decomposition hydrogenated Ti-6Al-4V hollow spheres emerge at 600 ° C (Synth./Process. Lightweight Met. Mater. II, Proc. Symp. 2nd (1997), 289-300).
ad 5) Schaumaluminium wird nach Infiltration geschmolzenen Aluminiums in einen porösen Füllstoff durch Entfernen desselben aus dem erstarrten Metall erhalten (Zhuzao Bianjibu (1997) (2) 1-4; ZHUZET, ISSN: 1001-4977).ad 5) Foam aluminum becomes molten aluminum after infiltration into a porous filler by removing it obtained from the solidified metal (Zhuzao Bianjibu (1997) (2) 1-4; ZHUZET, ISSN: 1001-4977).
Bei Würdigung des Standes der Technik ist festzustellen, daß die Verfahren, die ein Vorkompaktieren Treibmittel enthaltender Grünkörper vorsehen, aufwendig und kostspielig sind und sich nicht zur Herstellung von Massengütern eignen. Außerdem ist diesen Verfahren gemeinsam, daß die angestrebte Temperaturdifferenz zwischen dem Schmelzpunkt des zu schäumenden Metalls und der Zersetzungstemperatur des verwendeten Treibmittels möglichst gering sein soll, da sonst bereits während des Kompaktierens oder später in der Aufschmelzphase störende Treibmittelzersetzung stattfindet.When assessing the state of the art, it should be noted that the processes involving precompacting propellants Provide green bodies that are complex and costly not suitable for the production of bulk goods. Besides, is common to these processes is that the desired temperature difference between the melting point of the metal to be foamed and the decomposition temperature of the blowing agent used if possible should be low, otherwise it is already during compacting or later disruptive blowing agent decomposition in the melting phase takes place.
In Analogie dazu gilt diese Betrachtung auch für das Eintragen von Treibmitteln in Metallschmelzen.In analogy to this, this consideration also applies to the entry of blowing agents in molten metals.
Dem Versintern präformierter Hohlkugeln zu einem metallischen Schaum kommt allenfalls akademisches Interesse zu, da die Herstellung der Hohlkugeln bereits eine aufwendige Verfahrenstechnik erfordert.The sintering of preformed hollow spheres to a metallic one Foam is of academic interest at most, since the production the hollow spheres are already a complex process technology requires.
Unter diesem Aspekt ist auch die Infiltrationstechnik zu bewerten, bei der man mühevoll den porösen Füllstoff aus der Schaummatrix entfernen muß.The infiltration technology should also be assessed from this perspective, in which one painstakingly removes the porous filler from the foam matrix must remove.
Das Lösen bzw. Einblasen von Treibgasen in Metallschmelzen ist nicht zur Fertigung endkonturnaher Werkstücke geeignet, da ein System, bestehend aus der Schmelze mit okkludierten Gasblasen, nicht ausreichend zeitstabil ist, um in formgebenden Werkzeugen verarbeitet zu werden.The dissolving or blowing in of propellant gases in molten metal is not suitable for the production of near-net shape workpieces, because a System consisting of the melt with occluded gas bubbles, is not sufficiently stable in time to be used in shaping tools to be processed.
Vor diesem Hintergrund war es Aufgabe der Erfindung, ein einfaches und zugleich für die Massenfertigung taugliches Verfahren zur Herstellung von Metallschäumen bereitzustellen, das mit geringem Aufwand die Produktion von endkonturnahen Teilen gestattet und auf der Verwendung fester, gasgenerierender Treibmittel beruht.Against this background, it was an object of the invention to make a simple one and at the same time process suitable for mass production to provide for the production of metal foams that with low effort allows the production of near net shape parts and on the use of solid, gas-generating propellants based.
Erstaunlicherweise wurde nun gefunden, daß die Erzeugung metallischer Schäume weder mit Treibmittel versehene, kompaktierte Grünkörper noch das Eintragen von Treibmitteln in schmelzflüssige Metalle benötigt, wenn bestimmte verfahrenstechnische Randbedingungen eingehalten werden.Surprisingly, it has now been found that the production of metallic Foams neither compacted with blowing agents Green bodies still the introduction of blowing agents in molten Metals needed when certain process engineering Boundary conditions are observed.
In der einfachsten Ausführungsform des erfindungsgemäßen Verfahrens ist es zur Erzeugung eines porösen Metallkörpers hinreichend, eine geringe Menge des gasliefernden Treibmittels unter das zu verschäumende, pulverförmige Metall zu mischen und dieses Gemisch zügig zu erwärmen. Erhalten wird ein poröser Metallkörper.In the simplest embodiment of the method according to the invention it is sufficient to create a porous metal body, a small amount of the gas-producing propellant to mix the powdery metal to be foamed and to warm this mixture quickly. A porous metal body is obtained.
Die vorgenannte Aufgabe wird somit in einer ersten Ausführungsform
gelöst durch ein Verfahren zur Herstellung von Metallschäumen,
wobei man
ein oder mehrere Metallpulver, gegebenenfalls beaufschlagt mit
mehr oder minder stückigen metallischen oder nichtmetallischen,
z. B. mineralischen Zuschlagstoffen, mit einem gasabspaltenden
Treibmittel vermischt,
das Gemisch in einer offenen oder geschlossenen Form gegebenenfalls
auf eine Temperatur unterhalb der Zersetzungstemperatur
des Treibmittels vorerhitzt,
das Gemisch anschließend auf eine Temperatur oberhalb der
Schmelztemperatur des niedrigstschmelzenden Metalls so erhitzt,
daß die Temperaturdifferenz zwischen der Gleichgewichtszersetzungstemperatur
des Treibmittels und der Schmelztemperatur des
Metalls
bzw. der Schmelztemperatur des niedrigstschmelzenden metalls
in einem metallgemisch in einer Zeitspanne überbrückt wird, die kürzer ist als
die Zeit, die zur Erreichung des Gleichgewichtszustandes im System
Treibmittel//Treibgas bei dieser Temperatur erforderlich
ist und
den erhaltenen Metallschaum auf eine Temperatur unterhalb des
Schmelzpunktes des niedrigstschmelzenden Metalls abkühlt.The above object is thus achieved in a first embodiment by a method for producing metal foams, wherein
one or more metal powders, optionally applied with more or less lumpy metallic or non-metallic, e.g. B. mineral aggregates, mixed with a gas-releasing blowing agent,
the mixture in an open or closed form, if necessary preheated to a temperature below the decomposition temperature of the blowing agent,
the mixture is then heated to a temperature above the melting temperature of the low-melting metal,
that the temperature difference between the equilibrium decomposition temperature of the blowing agent and the melting temperature of the metal or the melting temperature of the lowest-melting metal in a metal mixture is bridged in a period of time that is shorter than the time required to reach the equilibrium state in the blowing agent / propellant system at this temperature is required and
cools the metal foam obtained to a temperature below the melting point of the lowest-melting metal.
Das erfindungsgemäße Verfahren verzichtet auf Methoden, die in der aufzuschäumenden Metallmatrix für den Aufbau eines dem Treibmitteldruck entgegenwirkenden, mechanischen Widerstandes verantwortlich sind. Essentiell für die vorliegende Erfindung ist jedoch, daß die Temperaturdifferenz zwischen der Gleichgewichtszersetzungstemperatur des Treibmittels und der Schmelztemperatur des Metalls bzw. der Schmelztemperatur des niedrigstschmelzenden Metalls in einem Metallgemisch in einer Zeitspanne überbrückt wird, die kürzer ist als die Zeit, die zur Erreichung des Gleichgewichtszustandes im System Treibmittel//Treibgas bei dieser Temperatur erforderlich ist.The method according to the invention dispenses with methods which are described in the metal matrix to be foamed for the construction of a Propellant pressure counteracting mechanical resistance are responsible. Essential to the present invention is, however, that the temperature difference between the equilibrium decomposition temperature of the blowing agent and the melting temperature of the metal or the melting temperature of the lowest melting point Metal in a metal mixture in one Time span that is shorter than the time that is to achieve equilibrium in the propellant // propellant system at this temperature is required.
Das rasche Erreichen der Schmelztemperatur des niedrigstschmelzenden Metalls in einem aufzuschäumenden Metallgemisch erlaubt in vorteilhafter Weise die Nutzung Endmatrix-verträglicher Komponenten (nichtgeschmolzene Metallpartikel) als die Gleichmäßigkeit des Metallschaums fördernde Keimbildner.The rapid reaching of the melting temperature of the lowest melting Metal in a metal mixture to be foamed advantageously allows the use of end matrix compatible Components (unmelted metal particles) than that Nucleation promoting the uniformity of the metal foam.
Zur schnellen Erhitzung der Reaktionsmasse dienen beispielsweise die Induktiverhitzung oder der Beschuß mit Laserstrahlung. In einer besonderen Modifizierung des vorgestellten Verfahrens kann aber auch anstelle oder zusätzlich zu dem externen Energieeintrag die Reaktionswärme eines schnellen, stark exothermen Prozesses (z. B. der aluminothermischen Reduktion) die Aufgabe übernehmen, sowohl Schmelzwärme für das zu verschäumende Metall als auch Zersetzungswärme für das verwendete Treibmittel zu liefern.For example, the reaction mass is heated quickly induction heating or bombardment with laser radiation. In a special modification of the method presented can also be used instead of or in addition to the external one Energy input the reaction heat of a fast, strongly exothermic Process (e.g. aluminothermic reduction) Take on the task of both melting heat for the foam to be foamed Metal as well as heat of decomposition for the used To deliver propellants.
Prinzipiell sind alle schmelzbaren Metalle oder Metall-Legierungen im Sinne der vorliegenden Erfindung schäumbar. Besonders bevorzugt im Sinne der vorliegenden Erfindung wird als Metallpulver Aluminium oder Eisen sowie deren Legierungen eingesetzt. Im Gegensatz zum üblichen Stand der Technik ist es somit möglich, nicht nur Leichtmetalle, sondern auch Schwermetalle in Schaumform herzustellen. In principle, all fusible metals or metal alloys foamable in the sense of the present invention. Especially preferred in the sense of the present invention is as metal powder Aluminum or iron and their alloys are used. In contrast to the usual state of the art, it is possible not only light metals but also heavy metals in To produce foam mold.
Besonders bevorzugt im Sinne der vorliegenden Erfindung wird Magnesiumhydrid als gasabspaltendes Treibmittel eingesetzt, das kommerziell erhältlich ist. Neben Magnesiumhydrid können aber auch an sich bekannte Metallhydride, beispielsweise Titanhydrid, sowie Carbonate, beispielsweise Calciumcarbonat, Kaliumcarbonat, Natriumcarbonat, Natriumbicarbonat, Hydrate, beispielsweise Aluminiumsulfathydrat, Alaun, Aluminiumhydroxid oder leicht verdampfende Stoffe, beispielsweise Quecksilberverbindungen oder pulverisierte organische Substanzen eingesetzt werden. Im Sinne der vorliegenden Erfindung ist es selbstverständlich besonders bevorzugt, wenn das gasabspaltende Treibmittel dieselben Metallionen enthält, die auch für das zu schmelzende Metall vorgesehen sind.Is particularly preferred in the sense of the present invention Magnesium hydride used as a gas-releasing blowing agent, the is commercially available. In addition to magnesium hydride, however also known metal hydrides, for example titanium hydride, and carbonates, for example calcium carbonate, potassium carbonate, Sodium carbonate, sodium bicarbonate, hydrates, for example Aluminum sulfate hydrate, alum, aluminum hydroxide or easily evaporating substances, for example mercury compounds or powdered organic substances used become. For the purposes of the present invention, it is Of course, particularly preferred if the gas-releasing Blowing agent contains the same metal ions as for the melting metal are provided.
Die erfindungsgemäß einzusetzende Menge des gasabspaltenden Treibmittels ist üblicherweise sehr gering. So reichen die Treibmittelanteile in der Größenordnung von mehreren Zehntel Gewichtsprozent üblicherweise aus. Als besonders günstig im Sinne der vorliegenden Erfindung haben sich Treibmittelmengen von 0,1 bis 10 Gew.-%, insbesondere 0,2 bis 5 Gew.-%, bezogen auf Metallpulver, erwiesen.The amount of gas-releasing to be used according to the invention Blowing agent is usually very low. So that's enough Blowing agent proportions in the order of several tenths Weight percent usually from. As particularly cheap in For the purposes of the present invention, amounts of blowing agent have increased from 0.1 to 10% by weight, in particular 0.2 to 5% by weight on metal powder.
Insbesondere im letztgenannten Fall war für den Fachmann vollkommen überraschend, daß sich beispielsweise Stahl mit einem Schmelzpunkt von 1500 °C bis 1600 °C mit Hilfe von Magnesiumhydrid (Tzersetzung ≥ 280 °C) als Treibmittel verschäumen läßt, wenn man eine kleine Menge MgH2 einer pulverförmigen THERMIT®-Mischung zusetzt und dann durch Zündung des Reaktionsgemisches die aluminothermische Reduktion von Eisenoxid zu Eisen initialisiert.In the latter case in particular, it was completely surprising to the person skilled in the art that steel with a melting point of 1500 ° C. to 1600 ° C., for example, can be foamed using magnesium hydride ( decomposition ≥ 280 ° C.) as a blowing agent if a small amount of MgH 2 is added to a powdered THERMIT® mixture and then the ignition of the reaction mixture initiates the aluminothermic reduction of iron oxide to iron.
Der nach dem Erkalten gewonnene und in der Längsrichtung aufgesägte Regulus gemäß Fig. 1 enthält auf Hydridzersetzung beruhende Gasporen im metallischen Eisen. The one obtained after cooling and sawed in the longitudinal direction Regulus according to FIG. 1 contains hydride decomposition Gas pores in metallic iron.
Diese Beobachtung ist absolut verblüffend, da weder eine Vorkompaktierung der Pulvermischung notwendig war, noch die Prämisse einer möglichst kleinen Temperaturdifferenz zwischen dem Schmelzpunkt des Metalls und der Zersetzungstemperatur des Treibmittels erfüllt wurde. Darüber hinaus grenzt sich diese Beobachtung von den Verfahren ab, die auf einem nachträglichen Eintrag von Treibmitteln in die metallische Schmelze beruht, da das Ausgangsmaterial als Festkörpermischung vorlag.This observation is absolutely astounding, since neither precompaction the powder mixture was still necessary, the premise the smallest possible temperature difference between the Melting point of the metal and the decomposition temperature of the Propellant was met. In addition, this limits itself Observation of the procedures based on an ex post The introduction of blowing agents into the metallic melt is based on the starting material was in the form of a solid mixture.
Zugleich eröffnet diese erfindungsgemäße Ausführungsform das weite Feld einer "Reaktivverschäumung" von Metallen, wobei ein exotherm verlaufender Vorgang (beispielsweise eine Reduktion) zeitlich und räumlich an den Aufschäumvorgang (Treibmittelzersetzung und Bildung der Metallschmelze) gekoppelt wird.At the same time, this embodiment of the invention opens that wide field of "reactive foaming" of metals, with a exothermic process (e.g. a reduction) temporally and spatially to the foaming process (blowing agent decomposition and formation of the molten metal) is coupled.
Die nach dem erfindungsgemäßen Verfahren entbehrliche, mechanische Vorbehandlung der schaumbildenden Mischung läßt nahezu beliebige Formgebung bei den geschäumten Halbzeugen zu und bereitet einer Massenfertigung den Weg.The mechanical dispensable according to the inventive method Pretreatment of the foam-forming mixture leaves almost Any shape for the foamed semi-finished products and prepares the way to mass production.
Eine weitere Ausführungsform der vorliegenden Erfindung betrifft daher ein schaumförmiges Metallhalbzeug, das unter Einsatz des erfindungsgemäßen Verfahrens erhältlich ist.Another embodiment of the present invention relates hence a foam-shaped semi-finished metal product that is used of the method according to the invention is available.
Die Qualität des nach dem neuen Verfahren gewonnenen Metallschaums (Porengröße, Porenverteilung, etc.) hängt beispielsweise von der Abkühlrate der Metallmasse ab.The quality of the metal foam obtained using the new process (Pore size, pore distribution, etc.) depends, for example on the cooling rate of the metal mass.
In einem Tiegel werden 6 kg einer handelsüblichen THERMIT®-Mischung mit 200 g (3,3 m-%) autokatalytisch hergestellten Magnesiumhydrids versetzt. Durch einen Thermitzünder wird die aluminothermische Reduktionsreaktion initialisiert. Nach Abklingen der heftigen Reaktionsphase läßt man den Ansatz im Tiegel erkalten. Der metallische Regulus wird von Schlackenresten befreit und in Längsrichtung aufgesägt. Fig. 1 zeigt das Längsprofil des porösen Stahlkörpers.6 kg of a commercially available THERMIT® mixture are placed in a crucible with 200 g (3.3 m%) of autocatalytically produced magnesium hydride added. With a thermal igniter aluminothermic reduction reaction initialized. After decay the violent reaction phase, the approach is left in the crucible cool. The metallic regulus is made of slag residues freed and sawn lengthways. Fig. 1 shows the longitudinal profile of the porous steel body.
Claims (4)
- Process for producing metal foams, in which one or more metal powders, if appropriate with the addition of more or less lumpy metallic or non-metallic, e.g. mineral additions, is/are mixed with a gas-releasing blowing agent,
the mixture, in an open or closed mould, is preheated if appropriate to a temperature below the decomposition temperature of the blowing agent,
the mixture is then heated to a temperature above the melting point of the lowest-melting metal, in such a way that the temperature difference between the equilibrium decomposition temperature of the blowing agent and the melting point of the metal or the melting point of the lowest-melting metal in a metal mixture is covered within a period of time which is shorter than the time which is required to reach the equilibrium state in the blowing agent/blowing gas system at this temperature, and
the metal foam obtained is cooled to a temperature below the melting point of the lowest-melting metal. - Process according to Claim 1, characterized in that the energy required to melt the metal is introduced by induction heating, laser radiation and/or chemical reaction heat.
- Process according to Claim 1, characterized in that the gas-releasing blowing agent used is metal hydrides, in particular magnesium hydrides, carbonates, hydrates and/or substances which evaporate at the reaction temperature.
- Process according to one or more of Claims 1 to 3, characterized in that the gas-releasing blowing agent is used in an amount of from 0.1 to 10% by weight, in particular 0.2 to 5% by weight, based on metal powder.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19907855A DE19907855C1 (en) | 1999-02-24 | 1999-02-24 | Manufacture of metal foams |
| DE19907855 | 1999-02-24 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP1031393A1 EP1031393A1 (en) | 2000-08-30 |
| EP1031393B1 true EP1031393B1 (en) | 2004-01-28 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP00102816A Expired - Lifetime EP1031393B1 (en) | 1999-02-24 | 2000-02-11 | Preparation of metal foams |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US6444007B1 (en) |
| EP (1) | EP1031393B1 (en) |
| AT (1) | ATE258477T1 (en) |
| CA (1) | CA2298348C (en) |
| DE (2) | DE19907855C1 (en) |
| NO (1) | NO20000848L (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6852272B2 (en) * | 2001-03-07 | 2005-02-08 | Advanced Ceramics Research, Inc. | Method for preparation of metallic and ceramic foam products and products made |
| ATE357304T1 (en) * | 2001-05-19 | 2007-04-15 | Goldschmidt Gmbh | PRODUCTION OF METAL FOAM |
| DE10161348A1 (en) * | 2001-12-13 | 2003-06-26 | Trw Automotive Safety Sys Gmbh | vehicle steering wheel |
| WO2005113179A2 (en) * | 2004-05-14 | 2005-12-01 | Jeanette Garr | A process and system for manufacturing a metal foam product, and uses thereof |
| US7582361B2 (en) * | 2004-06-21 | 2009-09-01 | Purgert Robert M | Lightweight structural members |
| TW201003024A (en) * | 2008-04-28 | 2010-01-16 | Basf Se | Open-cell porous shaped bodies for heat exchangers |
| US20110111251A1 (en) * | 2009-11-10 | 2011-05-12 | Ken Evans | Process for producing a foamed metal article and process for producing a foamable metal precursor |
| US20150321289A1 (en) * | 2014-05-12 | 2015-11-12 | Siemens Energy, Inc. | Laser deposition of metal foam |
| DE102014209408A1 (en) | 2014-05-19 | 2015-11-19 | Evonik Degussa Gmbh | Ethoxylate preparation using highly active double metal cyanide catalysts |
| ES2676430T3 (en) | 2015-11-11 | 2018-07-19 | Evonik Degussa Gmbh | Curable polymers |
| PL3321304T3 (en) | 2016-11-15 | 2019-11-29 | Evonik Degussa Gmbh | Mixtures of cyclic branched d/t-type siloxanes and their ensuing products |
| EP3415547B1 (en) | 2017-06-13 | 2020-03-25 | Evonik Operations GmbH | Method for producing sic-linked polyether siloxanes |
| EP3415548B1 (en) | 2017-06-13 | 2020-03-25 | Evonik Operations GmbH | Method for producing sic-linked polyether siloxanes |
| EP3438158B1 (en) | 2017-08-01 | 2020-11-25 | Evonik Operations GmbH | Production of sioc-linked siloxanes |
| EP3467006B1 (en) | 2017-10-09 | 2022-11-30 | Evonik Operations GmbH | Mixtures of cyclic branched d/t-type siloxanes and their ensuing products |
| EP3611215A1 (en) | 2018-08-15 | 2020-02-19 | Evonik Operations GmbH | Method for producing acetoxy groups carrying siloxanes |
| EP3611214A1 (en) | 2018-08-15 | 2020-02-19 | Evonik Operations GmbH | Sioc-linked, linear polydimethylsiloxane polyoxyalkylene block copolymers |
| CN111250707B (en) * | 2020-03-14 | 2022-04-01 | 中北大学 | Composite metal foaming powder material based on selective laser melting forming technology and preparation method thereof |
| CN112662908B (en) * | 2021-01-04 | 2023-09-12 | 云南迈特力医疗技术有限公司 | Preparation device and method of porous low-melting-point metal exoskeleton |
| CN114871433A (en) * | 2022-04-21 | 2022-08-09 | 湖北黄石科创模具技术研究院有限公司 | Preparation method of porous breathable steel based on sodium bicarbonate particles |
| CN115074569B (en) * | 2022-07-21 | 2023-03-31 | 内蒙古环投环保技术有限公司 | Preparation method of porous copper alloy |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2895819A (en) * | 1957-09-03 | 1959-07-21 | Bjorksten Res Lab Inc | Method for preparing a catalytic metal foam and use thereof |
| US2983597A (en) * | 1959-06-11 | 1961-05-09 | Lor Corp | Metal foam and method for making |
| US3087807A (en) * | 1959-12-04 | 1963-04-30 | United Aircraft Corp | Method of making foamed metal |
| US3300296A (en) * | 1963-07-31 | 1967-01-24 | American Can Co | Method of producing a lightweight foamed metal |
| US3297431A (en) * | 1965-06-02 | 1967-01-10 | Standard Oil Co | Cellarized metal and method of producing same |
| EP0362411A4 (en) * | 1988-04-05 | 1991-03-27 | Kanegafuchi Kagaku Kogyo Kabushiki Kaisha | Foamable composition, process for its production, rigid foam, and process for its production |
| JPH0317236A (en) * | 1989-06-14 | 1991-01-25 | Nkk Corp | Manufacture of foamed metal |
| US4973358A (en) * | 1989-09-06 | 1990-11-27 | Alcan International Limited | Method of producing lightweight foamed metal |
| DE4101630A1 (en) * | 1990-06-08 | 1991-12-12 | Fraunhofer Ges Forschung | METHOD FOR PRODUCING FOAMABLE METAL BODIES AND USE THEREOF |
| CA2109957C (en) * | 1991-05-31 | 1998-12-15 | Harry Sang | Process and apparatus for producing shaped slabs of particle stabilized foamed metal |
| US5213612A (en) * | 1991-10-17 | 1993-05-25 | General Electric Company | Method of forming porous bodies of molybdenum or tungsten |
| DE4206303C1 (en) * | 1992-02-28 | 1993-06-17 | Mepura Metallpulver Ges.M.B.H., Ranshofen, At | |
| CH686413A5 (en) * | 1992-06-09 | 1996-03-29 | Matec Holding Ag | A process for the production of molded parts and application thereof. |
| DE19651197C2 (en) * | 1995-12-15 | 1999-10-28 | Susan Dietzschold | Material for producing porous metal bodies |
| JP3352584B2 (en) * | 1996-03-11 | 2002-12-03 | 神鋼鋼線工業株式会社 | Manufacturing method of metal foam |
| DE19734394C2 (en) * | 1996-08-13 | 2003-06-18 | Friedrich Wilhelm Bessel Inst | Method and device for producing metal foam |
| AT408076B (en) * | 1996-10-07 | 2001-08-27 | Mepura Metallpulver | METHOD FOR THE PRODUCTION OF FOAM METAL OR FOAM / METAL COMPOSITE MOLDED BODIES, SYSTEM FOR THE PRODUCTION AND USE THEREOF |
| EP0884123B1 (en) * | 1997-06-10 | 2003-03-26 | Goldschmidt AG | Foamable metal body |
-
1999
- 1999-02-24 DE DE19907855A patent/DE19907855C1/en not_active Expired - Fee Related
-
2000
- 2000-02-11 EP EP00102816A patent/EP1031393B1/en not_active Expired - Lifetime
- 2000-02-11 AT AT00102816T patent/ATE258477T1/en not_active IP Right Cessation
- 2000-02-11 DE DE50005107T patent/DE50005107D1/en not_active Expired - Lifetime
- 2000-02-14 CA CA002298348A patent/CA2298348C/en not_active Expired - Fee Related
- 2000-02-21 NO NO20000848A patent/NO20000848L/en not_active Application Discontinuation
- 2000-02-23 US US09/511,216 patent/US6444007B1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP1031393A1 (en) | 2000-08-30 |
| US6444007B1 (en) | 2002-09-03 |
| NO20000848L (en) | 2000-08-25 |
| CA2298348C (en) | 2008-06-17 |
| ATE258477T1 (en) | 2004-02-15 |
| NO20000848D0 (en) | 2000-02-21 |
| DE50005107D1 (en) | 2004-03-04 |
| DE19907855C1 (en) | 2000-09-21 |
| CA2298348A1 (en) | 2000-08-24 |
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