EP0334065A1 - Process for preparing porous elements - Google Patents

Process for preparing porous elements Download PDF

Info

Publication number
EP0334065A1
EP0334065A1 EP89103620A EP89103620A EP0334065A1 EP 0334065 A1 EP0334065 A1 EP 0334065A1 EP 89103620 A EP89103620 A EP 89103620A EP 89103620 A EP89103620 A EP 89103620A EP 0334065 A1 EP0334065 A1 EP 0334065A1
Authority
EP
European Patent Office
Prior art keywords
aluminum
sintering
powder
mixed
additive
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Withdrawn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
EP89103620A
Other languages
German (de)
French (fr)
Inventor
Michael Laumen
Kniep Prof. Dr. Rüdiger
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.)
Bayerische Motoren Werke AG
Original Assignee
Bayerische Motoren Werke 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 Bayerische Motoren Werke AG filed Critical Bayerische Motoren Werke AG
Publication of EP0334065A1 publication Critical patent/EP0334065A1/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Withdrawn legal-status Critical Current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
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/002—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature
    • B22F7/004—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature comprising at least one non-porous part
    • 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
    • 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
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0408—Light metal alloys
    • C22C1/0416—Aluminium-based alloys
    • 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
    • C22C1/10—Alloys containing non-metals
    • C22C1/1084—Alloys containing non-metals by mechanical alloying (blending, milling)
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/003—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by using permeable mass, perforated or porous materials
    • 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
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy

Definitions

  • the invention relates to a method for producing porous components from aluminum powder or grit according to the preamble of the first claim.
  • Porous components made of metal powder are widely used in the fields of filtering, heat transfer, sound insulation and as maintenance-free plain bearings. Such components are usually made of bronze or stainless steel powder. Disadvantages here are the high densities of the materials used, which lead to the high weight of such components, and the resulting high price per unit volume.
  • each aluminum powder contacted with a normal atmosphere has an oxide layer on the aluminum particles, the melting or flow temperature of which is substantially above the corresponding temperature of the aluminum or an aluminum alloy.
  • two-component systems ie to add additives to the aluminum powder compacted and evaporated during or after sintering or eliminated by chemical means.
  • the resulting voids form the porous volume fraction.
  • components sintered in this way have the disadvantage that neither channels and thus the desired flowability, nor a uniform pore diameter of a certain bandwidth are obtained. Therefore these components are not suitable for use in filter technology.
  • the object of the present invention is to provide a sintering process for components made from aluminum powder which is simple and inexpensive to carry out.
  • this object is achieved by the characterizing features of the first claim.
  • the invention is based on the knowledge that only one additive is necessary if care is taken to ensure that the additive and the aluminum powder can form a eutectic below the melting temperature of the aluminum.
  • Aluminum powder oxidized in air can thus be used, since the aggregate can render the oxide skin ineffective, so that a firm connection of the aluminum grains can be achieved. This can remove the oxide layer on the aluminum grains.
  • a metallic composite is thus obtained by forming a mixed crystal in contact with a eutectic structure. The structure of the powder layers, in particular their porosity, is retained.
  • the development according to claim 2 describes a preferred material with the process parameters for the aggregate.
  • the use of silicon as an additive is particularly advantageous since it can penetrate through the passivating oxide layer at sintering temperature.
  • the diffusion of the silicon can be further supported by mixing the two components, e.g. B. is carried out in a ball mill in a non-oxidizing atmosphere, whereby mechanical fractures in the oxide layer are achieved and obtained (claim 3).
  • the sintering temperature to be set depends on the silicon content in the aluminum and the amount of the aggregate.
  • the powder's morphology and sieve line, which determines the contact area, must also be taken into account. By varying the temperature, the proportion of the liquid phase rises or falls, so that the pore diameter of the component to be produced can be influenced in this way.
  • the oxide layer of the aluminum powder can essentially be broken up by the additive silicon in various ways.
  • the first way lies at the temperature specified in claim 2 in the ability of the silicon to diffuse through the oxide layer and thus to come into contact with the aluminum.
  • the second way consists in the direct contact of the silicon with the aluminum through fractures in the oxide layer or through mecha African pressure. This is supported in particular by mixing the two components in a ball mill, as taught in claim 3.
  • the third way consists in the formation of melting processes on the surface of the aluminum caused by the first two ways and the associated detachment of the oxide layer.
  • the actual sintering then takes place by melting aluminum-silicon on the surface or the area near the surface of the aluminum particles with subsequent solidification (crystallization) during cooling and a homogeneous connection of the contact surfaces.
  • the connection between the aluminum particles and the solidified melts is particularly good when very pure aluminum is sintered. This is primarily due to the mixed crystal formation of the silicon with the aluminum via diffusion and crystallization processes, which lead to continuous concentration gradients.
  • the non-oxidizing furnace atmosphere can be achieved by a protective gas. This increases the economics of the process, since the furnace heating times in an argon atmosphere are significantly shorter than, for example, in a vacuum furnace, since heat transfer by radiation and convection can be effective in the argon atmosphere.
  • the development according to claim 5 describes a further possible application of the method according to the invention.
  • This enables complete components to be made from solid metal units and porous sintered aluminum powder.
  • the metallic bond is achieved through the formation of mixed crystals in the boundary layer area. This is advantageous, for example, in the manufacture of heat exchangers for the purpose of better heat dissipation. It is important to ensure that the aggregate used can form a mixed crystal or a eutectic with both the aluminum powder and the component material.
  • a suitable material for this is described in claim 6.
  • the limit values already described for the aluminum powder with regard to the permissible additives are then to be taken into account.
  • the use of non-tempered aluminum components can prevent the embrittlement that otherwise occurs with commercially available aluminum due to the sintering temperatures. The remuneration takes place during the sintering process, so that the components coming out of the furnace system correspond to commercially available goods and thus, in addition to the property of having a metallic bond with the porous component, otherwise have normal material properties.
  • the sintering temperature must increase with a higher silicon content in the aluminum alloy, since diffusion processes are impeded by the already existing saturation.
  • the sintering temperature can be reduced by increasing the silicon content as an additive.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Composite Materials (AREA)
  • Dispersion Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Powder Metallurgy (AREA)

Abstract

The invention relates to a process for the production of heat exchangers from untreated, oxidised aluminium powder or aluminium grit by sintering, in which an additive which forms a mixed crystal or a eutectic mixture with the aluminium, below the melting point of the aluminium, in a non-oxidising furnace atmosphere at sinter temperatures is mixed with the aluminium powder or aluminium grit.

Description

Die Erfindung bezieht sich auf ein Verfahren zur Her­stellung poröser Bauteile aus Aluminiumpulver oder -gries nach dem Oberbegriff des ersten Anspruchs.The invention relates to a method for producing porous components from aluminum powder or grit according to the preamble of the first claim.

Aus Metallpulver gefertigte, poröse Bauteile finden im Bereich der Filterung, der Wärmeübertragung, der Schall­dämmung sowie als wartungsfreie Gleitlager vielfach Verwendung. Üblicherweise werden solche Bauteile aus Bronze- oder Edelstahlpulver hergestellt. Nachteilig sind hier die hohen Dichten der verwendeten Materialien, die zu einem hohen Gewicht solcher Bauteile führen sowie der daraus resultierende hohe Preis pro Volumeneinheit.Porous components made of metal powder are widely used in the fields of filtering, heat transfer, sound insulation and as maintenance-free plain bearings. Such components are usually made of bronze or stainless steel powder. Disadvantages here are the high densities of the materials used, which lead to the high weight of such components, and the resulting high price per unit volume.

Man ist deshalb schon dazu übergegangen, Aluminiumpulver einzusetzen, das neben ansonsten vergleichbaren Stoff­daten eine wesentlich bessere Wärmeleitfähigkeit auf­weist.It has therefore already started to use aluminum powder, which, in addition to comparable material data, has a much better thermal conductivity.

Hier besteht jedoch das Problem, daß jedes mit Normal­atmosphäre kontaktierte Aluminiumpulver eine Oxidschicht auf den Alumiumpartikeln aufweist, deren Schmelz- oder Fließtemperatur wesentlich oberhalb der entsprechenden Temperatur des Aluminiums oder einer Aluminiumlegierung liegt. Um hier Abhilfe zu schaffen, ist schon vorge­schlagen worden, Zweikomponentensysteme anzuwenden, also dem Aluminiumpulver Zuschlagstoffe beizumischen, die verdichtet und während oder nach der Sinterung ausge­dampft oder auf chemischem Wege eliminiert werden. Die hierbei entstehenden Hohlräume bilden den porösen Volumenanteil. Derart gesinterte Bauteile haben jedoch den Nachteil, daß man weder durchgängig Kanäle und somit die gewünschte Durchströmbarkeit, noch einen einheitlichen Porendurchmesser bestimmter Bandbreite erhält. Deshalb eignen sich diese Bauteile nicht zum Einsatz in der Filtertechnik.Here, however, there is the problem that each aluminum powder contacted with a normal atmosphere has an oxide layer on the aluminum particles, the melting or flow temperature of which is substantially above the corresponding temperature of the aluminum or an aluminum alloy. In order to remedy this, it has already been proposed to use two-component systems, ie to add additives to the aluminum powder compacted and evaporated during or after sintering or eliminated by chemical means. The resulting voids form the porous volume fraction. However, components sintered in this way have the disadvantage that neither channels and thus the desired flowability, nor a uniform pore diameter of a certain bandwidth are obtained. Therefore these components are not suitable for use in filter technology.

Aus der JP-A 61-174353 ist es bekannt, Aluminiumpulver mit anderen Zuschlagstoffen in Pulverform vor dem Sintern zu vermischen. Hierbei werden neben Aluminium­pulver einer nicht beschriebenen Qualität. Zuschlags­stoffe wie Kupfer, Mangan, Magnesium und Silicium in ebenfalls nicht beschriebenen Mengenverhältnissen beigefügt, wobei immer vom Zusatz von mindestens zwei dieser Stoffe ausgegangen wird. Weiterhin fehlen Angaben über Sintertemperaturen und Sinterzeiten.From JP-A 61-174353 it is known to mix aluminum powder with other additives in powder form before sintering. In addition to aluminum powder, the quality is not described here. Additives such as copper, manganese, magnesium and silicon are also added in proportions not described, whereby it is always assumed that at least two of these substances are added. Furthermore, information about sintering temperatures and sintering times is missing.

Aufgabe der vorliegenden Erfindung ist es, ein Sinter­verfahren für aus Aluminiumpulver hergestellte Bauteile bereitzustellen, das einfach und preiswert durchzuführen ist.The object of the present invention is to provide a sintering process for components made from aluminum powder which is simple and inexpensive to carry out.

Diese Aufgabe wird erfindungsgemäß durch die kennzeich­nenden Merkmale des ersten Anspruchs gelöst. Die Erfin­dung beruht auf der Erkenntnis, daß nur in einziger Zuschlagsstoff notwendig ist, wenn darauf geachtet wird, daß der Zuschlagsstoff sowie das Aluminiumpulver ein Eutektikum unterhalb der Schmelztemperatur des Alumi­niums bilden können. Damit kann an der Luft oxidiertes Aluminiumpulver Verwendung finden, da durch den Zu­schlagsstoff die Oxidhaut unwirksam gemacht werden kann, so daß eine feste Verbindung der Aluminiumkörner zu erzielen ist. Damit kann die Entfernung der Oxidschicht auf den Aluminiumkörnern entfallen. Man erhält somit einen metallischen Verbund durch Bildung eines Misch­kristalls in Kontakt mit einem eutektischen Gefüge. Hierbei bleibt die Struktur der Pulverschichten, ins­besondere deren Porösität erhalten.According to the invention, this object is achieved by the characterizing features of the first claim. The invention is based on the knowledge that only one additive is necessary if care is taken to ensure that the additive and the aluminum powder can form a eutectic below the melting temperature of the aluminum. Aluminum powder oxidized in air can thus be used, since the aggregate can render the oxide skin ineffective, so that a firm connection of the aluminum grains can be achieved. This can remove the oxide layer on the aluminum grains. A metallic composite is thus obtained by forming a mixed crystal in contact with a eutectic structure. The structure of the powder layers, in particular their porosity, is retained.

Die Weiterbildung nach Anspruch 2 beschreibt ein bevor­zugtes Material mit den Verfahrensparametern für den Zuschlagsstoff. Die Verwendung von Silicium als Zu­schlagsstoff ist insbesondere vorteilhaft, da es durch die passivierende Oxidschicht bei Sintertemperatur dringen kann. Die Diffusion des Siliciums kann weiterhin dadurch unterstützt werden, daß die Vermischung der beiden Komponenten, z. B. in einer Kugelmühle in nicht oxidierender Atmosphäre durchgeführt wird, wodurch mechanische Bruchstellen in der Oxidschicht erzielt und erhalten werden (Anspruch 3).The development according to claim 2 describes a preferred material with the process parameters for the aggregate. The use of silicon as an additive is particularly advantageous since it can penetrate through the passivating oxide layer at sintering temperature. The diffusion of the silicon can be further supported by mixing the two components, e.g. B. is carried out in a ball mill in a non-oxidizing atmosphere, whereby mechanical fractures in the oxide layer are achieved and obtained (claim 3).

Die einzustellende Sintertemperatur hängt ab von dem Siliciumanteil im Aluminium sowie der Menge des Zu­schlagsstoffes. Auch die Morphologie und die Sieblinie des Pulvers, durch die die Kontaktfläche bestimmt wird, ist zu berücksichtigen. Durch Variierung der Temperatur steigt oder fällt der Anteil der flüssigen Phase, so daß auf diese Weise der Porendurchmesser des herzustellenden Bauteils beeinflußt werden kann.The sintering temperature to be set depends on the silicon content in the aluminum and the amount of the aggregate. The powder's morphology and sieve line, which determines the contact area, must also be taken into account. By varying the temperature, the proportion of the liquid phase rises or falls, so that the pore diameter of the component to be produced can be influenced in this way.

Die Oxidschicht des Aluminiumpulvers kann also gemäß der Erfindung von dem Zuschlagsstoff Silicium auf verschie­dene Arten im wesentlichen aufgebrochen werden. Der erste Weg liegt bei der nach Anspruch 2 angegebenen Temperatur in der Fähigkeit des Siliciums, durch die Oxidschicht zu diffundieren und damit in Kontakt zu dem Aluminium zu gelangen. Der zweite Weg besteht in dem unmittelbaren Kontakt des Siliciums mit dem Aluminium durch Bruchstellen in der Oxidschicht bzw. durch mecha­ nischen Druck. Dies wird insbesondere durch das Ver­mischen der beiden Komponenten in einer Kugelmühle unterstützt, wie Anspruch 3 lehrt. Der dritte Weg besteht in dem durch die beiden ersten Wege hervor­gerufenen Entstehen von Schmelzprozessen auf der Ober­fläche des Aluminiums und der damit verbundenen Ablösung der Oxidschicht. Die eigentliche Versinterung erfolgt dann durch ein Aluminium-Silicium-Schmelzen auf der Oberfläche bzw. dem oberflächennahen Bereich der Alu­miniumpartikel mit anschließendem Erstarren (Kristal­lisation) beim Abkühlen und homogener Verbindung der Kontaktflächen. Die Verbindung zwischen den Aluminium­teilchen und den erstarrten Schmelzen ist dann besonders gut, wenn sehr reines Aluminium versintert wird. Dies beruht in erster Linie auf der Mischkristallbildung des Siliciums mit dem Aluminium über Diffusions- und Kristallisationsprozesse, die zu kontinuierlichen Konzentrationsgradienten führen.According to the invention, the oxide layer of the aluminum powder can essentially be broken up by the additive silicon in various ways. The first way lies at the temperature specified in claim 2 in the ability of the silicon to diffuse through the oxide layer and thus to come into contact with the aluminum. The second way consists in the direct contact of the silicon with the aluminum through fractures in the oxide layer or through mecha African pressure. This is supported in particular by mixing the two components in a ball mill, as taught in claim 3. The third way consists in the formation of melting processes on the surface of the aluminum caused by the first two ways and the associated detachment of the oxide layer. The actual sintering then takes place by melting aluminum-silicon on the surface or the area near the surface of the aluminum particles with subsequent solidification (crystallization) during cooling and a homogeneous connection of the contact surfaces. The connection between the aluminum particles and the solidified melts is particularly good when very pure aluminum is sintered. This is primarily due to the mixed crystal formation of the silicon with the aluminum via diffusion and crystallization processes, which lead to continuous concentration gradients.

Kontinuierliche Konzentrationsgradienten in den Kon­taktbereichen sind nicht mehr zu verwirklichen, wenn der Gesamtsiliciumanteil bei Silicium als Zuschlagswerkstoff und dem Siliciumlegierungsanteil in dem Aluminiumaus­gangswerkstoff 12 Gewichtsprozent übersteigt.Continuous concentration gradients in the contact areas can no longer be achieved if the total silicon content in silicon as the additive material and the silicon alloy content in the aluminum starting material exceeds 12 percent by weight.

Die nicht oxidierende Ofenatmosphäre kann nach einer Weiterbildung (Anspruch 4) der Erfindung durch ein Schutzgas erreicht werden. Dadurch wird die Wirtschaft­lichkeit des Verfahrens erhöht, da die Ofenaufheizzeiten in Argonatmosphäre wesentlich kürzer sind als z.B. in einem Vakuumofen, da bei der Argonatmosphäre eine Wärmeübertragung durch Strahlung und Konvektion wirksam werden kann.According to a further development (claim 4) of the invention, the non-oxidizing furnace atmosphere can be achieved by a protective gas. This increases the economics of the process, since the furnace heating times in an argon atmosphere are significantly shorter than, for example, in a vacuum furnace, since heat transfer by radiation and convection can be effective in the argon atmosphere.

Die Weiterbildung nach Anspruch 5 beschreibt eine weitere Einsatzmöglichkeit des erfindungsgemäßen Ver­fahrens. Dadurch können komplette Bauteile aus massiven Metalleinheiten und porös gesintertem Aluminiumpulver hergestellt werden. Hier wird der metallische Verbund durch die Bildung von Mischkristallen im Grenzschicht­bereich erzielt. Dies ist beispielsweise bei der Her­stellung von Wärmetauschern zwecks besserer Wärmeab­leitung günstig. Hierbei ist darauf zu achten, daß der verwendete Zuschlagsstoff sowohl mit dem Aluminiumpulver als auch mit dem Bauteilmaterial einen Mischkristall bzw. ein Eutektikum bilden kann.The development according to claim 5 describes a further possible application of the method according to the invention. This enables complete components to be made from solid metal units and porous sintered aluminum powder. Here, the metallic bond is achieved through the formation of mixed crystals in the boundary layer area. This is advantageous, for example, in the manufacture of heat exchangers for the purpose of better heat dissipation. It is important to ensure that the aggregate used can form a mixed crystal or a eutectic with both the aluminum powder and the component material.

Ein geeignetes Material hierfür beschreibt Anspruch 6. Hierbei sind dann die bereits für das Aluminiumpulver geschilderten Grenzwerte hinsichtlich der zulässigen Zuschlagsstoffe zu berücksichtigen. Durch die Verwendung unvergüteter Aluminiumbauteile kann die sonst bei handelsüblichen Aluminium auftretende Versprödung aufgrund der Sintertemperaturen verhindert werden. Die Vergütung findet hierbei während des Sinterprozesses statt, so daß die aus der Ofenanlage gelangenden Bau­teile handelsüblicher Ware entsprechen und somit neben der Eigenschaft, einen metallischen Verbund mit dem porösen Bauteil aufzuweisen, ansonsten normale Werk­stoffeigenschaften haben.A suitable material for this is described in claim 6. The limit values already described for the aluminum powder with regard to the permissible additives are then to be taken into account. The use of non-tempered aluminum components can prevent the embrittlement that otherwise occurs with commercially available aluminum due to the sintering temperatures. The remuneration takes place during the sintering process, so that the components coming out of the furnace system correspond to commercially available goods and thus, in addition to the property of having a metallic bond with the porous component, otherwise have normal material properties.

Im folgenden wird ein Beispiel des erfindungsgemäßen Verfahrens beschrieben.An example of the method according to the invention is described below.

Beispiel:Example:

Es wurde Aluminiumpulver mit einem Reinaluminiumanteil von 99,9 %, einer glatten Oberfläche und einer Korngröße von 200 - 500 µm mit einem Siliciumanteil von 5 Ge­wichtsprozenten gemischt. Dieses Gemisch wurde einer Sintertemperatur von 600°C fünf Minuten ausgesetzt. Die fünf Minuten Haltezeit beziehen sich auf einen auf 600°C vorgeheizten Ofen. Es wurden formstabile Sinterkörper erzielt.It was mixed aluminum powder with a pure aluminum content of 99.9%, a smooth surface and a grain size of 200 - 500 microns with a silicon content of 5 percent by weight. This mixture was exposed to a sintering temperature of 600 ° C for five minutes. The a five minute hold time refers to an oven preheated to 600 ° C. Dimensionally stable sintered bodies were achieved.

Allgemein kann festgehalten werden, daß mit höherem Siliciumanteil in der Aluminiumlegierung die Sintertem­peratur steigen muß, da durch die bereits vorliegende Sättigung Diffusionsvorgänge behindert werden. Anderer­seits kann bei reinem Aluminium durch Erhöhung des Siliciumanteils als Zuschlagsstoff die Sintertemperatur erniedrigt werden.In general, it can be stated that the sintering temperature must increase with a higher silicon content in the aluminum alloy, since diffusion processes are impeded by the already existing saturation. On the other hand, in the case of pure aluminum, the sintering temperature can be reduced by increasing the silicon content as an additive.

Claims (6)

1. Verfahren zum Herstellen poröser Bauteile aus unbehandeltem, oxidiertem Aluminiumpulver oder -gries durch Sintern,
dadurch gekennzeichnet, daß dem Aluminiumpulver oder -gries ein Zuschlagstoff beigemischt wird, der in einer nicht oxidierenden Ofenatmosphäre bei Sintertemperaturen einen Mischkristall bzw. ein Eutektikum mit dem Aluminium, unterhalb der Schmelztemperatur des Aluminiums, bildet.1. A method for producing porous components from untreated, oxidized aluminum powder or grit by sintering,
characterized in that an additive is mixed with the aluminum powder or grit, which forms a mixed crystal or a eutectic with the aluminum, below the melting temperature of the aluminum, in a non-oxidizing furnace atmosphere at sintering temperatures. 2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet, daß das Aluminiumaus­gangsmaterial eine Aluminiumlegierung aus Rein­aluminiumanteilen größer 96 % und Siliciumanteilen kleiner 0,5 % ist, daß als Zuschlagsstoff ge­pulvertes Silicium von 0,5 - 5 Gewichtsprozenten als Dispersion beigemischt wird und daß abhängig von der gewählten Aluminiumpulverfraktion eine Sintertemperatur zwischen 577° und 650°C einge­stellt wird.2. The method according to claim 1,
characterized in that the aluminum starting material is an aluminum alloy of pure aluminum portions greater than 96% and silicon portions less than 0.5%, that powdered silicon of 0.5-5 percent by weight is added as a dispersion and that, depending on the aluminum powder fraction chosen, a sintering temperature between 577 ° and 650 ° C is set. 3. Verfahren nach Anspruch 1 oder 2,
dadurch gekennzeichnet, daß das Aluminiumaus­gangsmaterial und der Zuschlagstoff in einer kugelmühle in nicht oxidierender Atmosphäre ge­mischt werden.3. The method according to claim 1 or 2,
characterized in that the aluminum raw material and the additive are mixed in a ball mill in a non-oxidizing atmosphere. 4. Verfahren nach einem der vorangegangenen Ansprüche,
dadurch gekennzeichnet, daß zur Erzeugung der nicht oxidierenden Ofenatmosphäre Argon als Schutzgas verwendet wird.4. The method according to any one of the preceding claims,
characterized in that argon is used as the protective gas to generate the non-oxidizing furnace atmosphere. 5. Verfahren nach einem der vorangegangenen Ansprüche,
dadurch gekennzeichnet, daß während des Sintervor­ganges das zu versinternde Pulvermaterial mit einem Bauteil in Kontakt gelangt, dessen chemische Beschaffenheit eine Reaktion an seiner Oberfläche im Bereich der Sintertemperatur erlaubt.5. The method according to any one of the preceding claims,
characterized in that during the sintering process the powder material to be sintered comes into contact with a component whose chemical nature allows a reaction on its surface in the range of the sintering temperature. 6. Verfahren nach Anspruch 5,
dadurch gekennzeichnet, daß das Bauteil aus unver­gütetem Aluminium besteht.6. The method according to claim 5,
characterized in that the component consists of unrefined aluminum.
EP89103620A 1988-03-19 1989-03-02 Process for preparing porous elements Withdrawn EP0334065A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3809345A DE3809345A1 (en) 1988-03-19 1988-03-19 METHOD FOR PRODUCING POROUS COMPONENTS
DE3809345 1988-03-19

Publications (1)

Publication Number Publication Date
EP0334065A1 true EP0334065A1 (en) 1989-09-27

Family

ID=6350221

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89103620A Withdrawn EP0334065A1 (en) 1988-03-19 1989-03-02 Process for preparing porous elements

Country Status (2)

Country Link
EP (1) EP0334065A1 (en)
DE (1) DE3809345A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4034637A1 (en) * 1989-10-31 1991-05-02 Eckart Standard Bronzepulver Porous sintered aluminium (alloy) body prodn. - from ground mixt. contg. eutectic-forming additive
JP3007868B2 (en) * 1997-03-11 2000-02-07 マツダ株式会社 Porous metal body, light alloy composite member, and production method thereof

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1588346A (en) * 1968-02-12 1970-04-10
FR2260405A1 (en) * 1974-02-13 1975-09-05 Alcan Res & Dev
JPS5524937A (en) * 1978-08-10 1980-02-22 N D C Kk Manufacture of porous sintered body
JPS5966918A (en) * 1982-10-12 1984-04-16 Showa Denko Kk Double layer structure hollow member made of aluminum alloy
EP0180144A1 (en) * 1984-10-23 1986-05-07 Inco Alloys International, Inc. Dispersion strengthened aluminum alloys
JPS61174353A (en) * 1985-01-29 1986-08-06 N D C Kk Porous al-type sintered material
JPS62188708A (en) * 1986-02-15 1987-08-18 Sumitomo Metal Ind Ltd Production of low-oxygen low-carbon metallic powder for sintering

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1588346A (en) * 1968-02-12 1970-04-10
FR2260405A1 (en) * 1974-02-13 1975-09-05 Alcan Res & Dev
JPS5524937A (en) * 1978-08-10 1980-02-22 N D C Kk Manufacture of porous sintered body
JPS5966918A (en) * 1982-10-12 1984-04-16 Showa Denko Kk Double layer structure hollow member made of aluminum alloy
EP0180144A1 (en) * 1984-10-23 1986-05-07 Inco Alloys International, Inc. Dispersion strengthened aluminum alloys
JPS61174353A (en) * 1985-01-29 1986-08-06 N D C Kk Porous al-type sintered material
JPS62188708A (en) * 1986-02-15 1987-08-18 Sumitomo Metal Ind Ltd Production of low-oxygen low-carbon metallic powder for sintering

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Band 10, Nr. 383 (C-393)[2440], 23. Dezember 1984; & JP-A-61 174 353 (NDC K.K.) 06-08-1986 *
PATENT ABSTRACTS OF JAPAN, Band 12, Nr. 36 (M-664)[2883], 3. Februar 1988; & JP-A-62 188 708 (SUMITOMO METAL IND. LTD) 18-08-1987 *
PATENT ABSTRACTS OF JAPAN, Band 4, Nr. 57 (M-009)[539], 26. April 1980, Seite 140 M 9; & JP-A-55 24 937 (NIPPON DIA CLEVITE K.K.) 22-02-1980 *
PATENT ABSTRACTS OF JAPAN, Band 8, Nr. 174 (M-316)[1611], 10. August 1984; & JP-A-59 66 918 (SHOWA DENKO K.K.) 16-04-1984 *

Also Published As

Publication number Publication date
DE3809345A1 (en) 1989-10-05

Similar Documents

Publication Publication Date Title
DE2940290C2 (en)
DE2942345C2 (en)
DE3514997A1 (en) METHOD FOR PRODUCING ALUMINUM ALLOY STRUCTURES
WO2006131129A1 (en) Aluminium plain bearing alloy
DE19950595C1 (en) Production of sintered parts made of aluminum sintered mixture comprises mixing pure aluminum powder and aluminum alloy powder to form a sintered mixture, mixing with a pressing auxiliary agent, pressing, and sintering
DE3344450A1 (en) ENGINE FASTENERS BASED ON ALUMINUM ALLOYS AND INTERMETALLIC COMPOUNDS AND METHOD FOR THE PRODUCTION THEREOF
DE2643091C2 (en) Non-hygroscopic phosphate-containing grain refiner for aluminum alloys with a high silicon content and process for its manufacture
EP0554808A1 (en) Method to produce metal parts
EP1017867A1 (en) Aluminium based alloy and method for subjecting it to heat treatment
DE2749215C2 (en) Process for the production of a copper-containing iron powder
DE2520865C3 (en) Process for reducing the grain sizes in aluminum or aluminum alloys
CH646999A5 (en) OBJECT OF A HIGH-STRENGTH ALUMINUM ALLOY AND METHOD FOR THE PRODUCTION THEREOF.
DE1458349B2 (en) SINTERED MATERIAL MADE FROM ALUMINUM OR AN ALUMINUM ALLOY POWDER AND GLASS POWDER
DE2217897A1 (en) Master alloys for aluminum alloys and processes for their manufacture
CH497535A (en) Process for the production of a beryllium-aluminum-silver alloy and the alloy produced according to this process
EP0219629A1 (en) Heat-resisting aluminium alloy and process for its manufacture
DE2339747A1 (en) PROCESS FOR PREPARING A LIQUID SOLID MIXTURE BASED ON METAL ALLOYS FOR THE CASTING PROCESS
EP0334065A1 (en) Process for preparing porous elements
DE3729509C2 (en) Improved copper alloy, especially for the production of electronic components
DE1817038B2 (en) Process for the production of a material for plain bearings
DE19800433C2 (en) Continuous casting process for casting an aluminum plain bearing alloy
DE2728287A1 (en) STEEL POWDER CONTAINING PHOSPHORUS AND METHOD FOR MANUFACTURING IT
DE2241243C2 (en) Process for increasing the resistance of brass to dezincification
DE4193445C1 (en) Beryllium / beryllium oxide mixed materials
DE2508450A1 (en) PROCESS FOR PRODUCING MAGNESIUM COMPOUNDS AND FOR GENERATING HYDROGEN FROM THESE COMPOUNDS

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE ES FR GB IT SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19900328