WO2008086930A1 - Ceramic preform for the production of metal-ceramic composite materials - Google Patents

Ceramic preform for the production of metal-ceramic composite materials Download PDF

Info

Publication number
WO2008086930A1
WO2008086930A1 PCT/EP2007/064070 EP2007064070W WO2008086930A1 WO 2008086930 A1 WO2008086930 A1 WO 2008086930A1 EP 2007064070 W EP2007064070 W EP 2007064070W WO 2008086930 A1 WO2008086930 A1 WO 2008086930A1
Authority
WO
WIPO (PCT)
Prior art keywords
metal
ceramic
preform
volume
produced
Prior art date
Application number
PCT/EP2007/064070
Other languages
German (de)
French (fr)
Inventor
Gert Lindemann
Matthias Leonhardt
Original Assignee
Robert Bosch Gmbh
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 Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2008086930A1 publication Critical patent/WO2008086930A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
    • C04B41/51—Metallising, e.g. infiltration of sintered ceramic preforms with molten metal
    • C04B41/5127—Cu, e.g. Cu-CuO eutectic
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
    • C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/581—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on aluminium nitride
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/71—Ceramic products containing macroscopic reinforcing agents
    • C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
    • C04B35/80—Fibres, filaments, whiskers, platelets, or the like
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
    • C04B38/063—Preparing or treating the raw materials individually or as batches
    • C04B38/0635—Compounding ingredients
    • C04B38/0645—Burnable, meltable, sublimable materials
    • C04B38/0675—Vegetable refuse; Cellulosic materials, e.g. wood chips, cork, peat, paper
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
    • C04B38/063—Preparing or treating the raw materials individually or as batches
    • C04B38/0635—Compounding ingredients
    • C04B38/0645—Burnable, meltable, sublimable materials
    • C04B38/068—Carbonaceous materials, e.g. coal, carbon, graphite, hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/81—Coating or impregnation
    • C04B41/89—Coating or impregnation for obtaining at least two superposed coatings having different compositions
    • C04B41/90—Coating or impregnation for obtaining at least two superposed coatings having different compositions at least one coating being a metal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
    • F16D69/02—Compositions of linings; Methods of manufacturing
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00241—Physical properties of the materials not provided for elsewhere in C04B2111/00
    • C04B2111/00362—Friction materials, e.g. used as brake linings, anti-skid materials

Definitions

  • the present invention relates to a ceramic preform for the production of metal-ceramic composite materials according to the preamble of claim 1.
  • tribologically (i.e., on friction) loaded components in particular on the brake discs used in vehicles require materials with high corrosion and wear resistance, high thermal conductivity and high mechanical strength up to temperatures of 800 ° C.
  • Usual materials, such as Gray cast iron, can no longer meet these high future requirements.
  • a new material approach is composites based on corrosion-resistant metal phases and temperature-resistant and wear-reducing ceramic components, in particular copper-based metal-ceramic composites (MMC) or ceramic-matrix composites (CMC)).
  • the published patent application DE 103 50 035 A1 describes a method for producing a composite component, preferably a brake disk, which is provided by pressure-assisted infiltration of a ceramic preform made of oxides, metal carbides or nitrides with a melt of copper alloy such as CuAl, CuMg or CuSi. It was relevant here that the element alloyed with the copper reacts with at least one of the ceramic phases in the course of the infiltration.
  • a ceramic preform made of oxides, metal carbides or nitrides with a melt of copper alloy such as CuAl, CuMg or CuSi.
  • Copper alloy allowed the use of much lower melting temperature than that of pure copper, while reactive infiltration improved the infiltratability while at the same time improving the thermal conductivity of the metal in the composite by dissociating the alloy.
  • the desired reaction of the melting temperature-reducing alloying constituents with the ceramic and thereby to achieve an increase in the temperature resistance of the composite body proves to be difficult to accomplish.
  • the reaction is very incomplete, therefore, especially in large-volume components results in a very inhomogeneous microstructure.
  • a strength-reducing porosity can not be excluded, since the volume fractions of the reaction products are always smaller than those of the educts. Even small residual components of mixed crystals of unreacted Cu alloy reduce the required thermal conductivity inadmissibly.
  • the preform has only a relatively low strength and therefore only small pressures can be applied to the infiltration.
  • Object of the present invention is therefore, a A process for producing a preform for the production of metal-ceramic composites, in particular for tribological applications, to provide, which allows the production of precursors, which have a higher strength and a higher thermal shock resistance and thus allow infiltration, in particular with refractory metals or metal alloys ,
  • a method for producing a ceramic preform for producing a metal-ceramic composite material in particular for tribological applications, wherein a starting ceramic powder, a glass frit having substantially silicate and / or oxidic constituents in a volume fraction of 1 to 15% by volume inclusive is added.
  • glass frit is understood to mean an intermediate in the production of glass melts.
  • the glass frit is formed by superficial melting of glass powder, whereby the glass grains cake together. The result is a porous material with a large inner surface.
  • Sintering temperatures are between 1000 ° C and 1700 ° C, preferred sintering times between 1 and 6 hours.
  • the porosity of the preform is 20-70% by volume, preferably 25-60% by volume. Porosity is to be understood as meaning the ratio of the volume of all cavities of a porous solid to its outer volume, the cavities being generally networked together and being in exchange or interconnected with the atmosphere surrounding the porous solid (so-called open porosity). It is therefore a measure of how much space the actual solid fills within a certain volume or which cavities it leaves in this volume. The pores are usually filled with air.
  • the pore diameter is preferably 0.5-10 ⁇ m, and more preferably 1-5 ⁇ m.
  • the volume fraction of the glass frit is particularly preferably 2-8 vol .-%.
  • the glass frit according to the invention consists of silicate and / or oxidic constituents. These ingredients are selected such that the glass frit has a softening interval that is below the original sintering temperature of 1000 ° C to 1700 ° C.
  • the sintering temperature can be reduced in comparison to green bodies without glass frit, since sintered necks of glass material form during sintering. Because the glass frit softened at the set sintering temperatures, moreover, there is a proportionate liquid phase sintering.
  • the resulting ceramic body has an increased high-temperature strength and thermal shock resistance, which has a positive effect in particular in the course of the preheating procedure of the ceramic preform preceding the infiltration as well as the infiltration with refractory metals or metal alloys.
  • ceramic fibers in a volume fraction of 1 to 60 vol .-%, and / or pore forming agent in a volume fraction of 1 to 30 vol .-% are added to the ceramic starting powder.
  • the ceramic fibers not only significantly increase the mechanical strength, in particular the high-temperature mechanical strength, of the metal-ceramic composite, but also that of the ceramic preform prior to infiltration. The latter in turn has a positive effect on the precursor stability in the course of the infiltration.
  • the ceramic fibers are metallic or ceramic fibers, preferably oxide-ceramic fibers, more preferably fibers consisting essentially of Al 2 O 3 . It may be continuous or short fibers with a diameter of about 2 microns to 20 microns. These are preferably added to the starting ceramic powder in a volume fraction of 10 to 50% by volume. These fibers can be added loosely to the starting powder, or in the form of an insert of woven continuous Al 2 O 3 fibers.
  • the pore builders are elongated, easily burnable substances that burn during sintering, creating a network of channels and pores that facilitate subsequent infiltration of the molten metal and allow intimate bonding between the preform and the solidifying metal.
  • the channels produced in this way can have widths of 2 to 50 ⁇ m, preferably 5 to 30 ⁇ m. By the channels filling in the finished body metal channels, the strength and toughness of the body is further increased.
  • the pore formers have - besides the set sintering parameters - a significant influence on the setting of a certain porosity.
  • pore formers can also be used in particular in the production of ceramic preforms in order to produce a network of pore channels, which result in a better infiltrability of the preform; the pore channels act as infiltration channels here.
  • the resulting metal channels increase the strength and toughness of the material, and create a large internal surface that provides space for reactions between the ceramic material of the preform and the metal phase.
  • Cellulose flakes or fibers having a volume fraction of 1 to 30%, preferably 2 to 20%, are particularly preferably used here.
  • pore formers are, for example, soot particles, rice starch or organic macromolecules, such as, for example, fullerenes or nanotubes. In essence, pore formers are all those materials that burn during sintering, disintegrate or outgas, thus creating voids in the material.
  • the ceramic starting material is one or more materials selected from the group consisting of oxides, carbides, nitrides, borides and / or silicates.
  • oxides such as e.g. Al 2 O 3 or TiO 2, carbides, e.g. SiC, or nitrides, e.g. Si3N4 or AlN, or mixtures of the aforementioned substances in question.
  • a ceramic preform for producing a metal-ceramic composite material which is produced according to one of the preceding methods.
  • the preform has a pore structure with a total porosity of 20-70% by volume, preferably 25-60% by volume.
  • the pores have diameters between 0.5 and 10 .mu.m, preferably 1-5 .mu.m.
  • a method for producing a metal-ceramic composite material from a preform according to one of the preceding claims is provided according to the invention, wherein the preform is infiltrated with a melt of metal or a metal alloy.
  • refractory metals or high-melting metal alloys are used, such as copper or copper alloys.
  • a refractory metal phase is compared to low-melting metal phases - eg aluminum-based alloys - a significantly higher operating temperature of metal-ceramic composites possible.
  • the materials according to the invention can therefore be used, for example, as friction materials such as brake materials for a much wider range of applications.
  • Metal-ceramic composites based on lower melting metal phases such as cast aluminum alloys
  • high-stress friction materials e.g., in brake discs in heavy and powerful vehicles, so in particular middle and luxury vehicles, SUVs, vans and sports cars, high
  • the ceramic preform produced by the method of the present invention has a microstructure and composition involving infiltration with a refractory metal or refractory metal alloy, e.g. pure copper, favors or only allows.
  • a refractory metal or refractory metal alloy e.g. pure copper
  • the inventive method At the same time an improvement of the application-specific property profile is achieved by the inventive method.
  • the ceramic preforms have to withstand the high pressures and high temperatures required in the infiltration process.
  • the inventively achievable defined pore structure of the preform supports melt infiltration. As a result, a high infiltration quality is achieved resulting in metal-ceramic composites with little to no residual porosity.
  • lower infiltration pressures can also be used.
  • the preform has previously been brought to a temperature close to the melting temperature of the metal or the metal alloy (infiltration step).
  • the temperature difference should not be greater than 350 ° C, preferably not greater than 100 ° C. This can be ensured, for example, by preheating the preform prior to infiltration.
  • An additional measure may be to surround the preheated ceramic preform with an insulating sheath, e.g. with ceramic paper or fleece.
  • the infiltration with molten metal is preferably reaction-assisted, i. it finds a suitable choice of ceramic and metal phase on the surface zone of the
  • Ceramic phase limited reaction with the metal phase instead.
  • an alloying element may also be reactive in connection with ceramic fractions.
  • the quality of infiltration can be improved and the infiltration pressure can be lowered. The reason for this is the released Reaction heat or the changed surface tension due to the newly formed interface phase.
  • the melt of metal or a metal alloy is infiltrated by applying an external pressure.
  • gas pressure infiltration or melt-infiltration come here means of the known technique of "squeeze casting" in question.
  • the metal alloy it is preferably copper or a copper alloy selected from the group consisting of Cu-ETP, CuMg x, CuAl x, CuSi x , CuZr x , CuTi x , CuZn x and / or CuAl x Fe ⁇ Ni z .
  • a metal-ceramic composite material is provided, which was produced by a method according to one of the preceding claims.
  • Ceramic preforms were produced from a ceramic starting powder, which consists of 60% by volume of TiO 2,
  • the sintering temperature is reduced compared to green bodies without glass frit, as formed during sintering sintered necks of glass material. Since the glass frit softens at the set sintering temperatures, a proportionate liquid phase sintering takes place. As a result, there is a reduction in sintering shrinkage at high temperatures, e.g. occur during preheating of the preform prior to infiltration or during infiltration, resulting in an improvement in process stability. Also, such processed composite materials show higher strength and higher thermal shock resistance.
  • micrograph of a metal-ceramic composite body produced by the method according to the invention shown in FIG. 1 shows the resulting microstructure:

Abstract

The object of the invention is a method for producing a ceramic preform for the production of a metal-ceramic composite material, particularly for tribological applications, wherein to a ceramic starting powder a glass frit is added, having substantially siliceous and/or oxidic components, in a volume percentage of 1 to 15% by volume, and/or ceramic fibers, in a volume percentage of 1 to 60% by volume, and/or pore-forming agents, in a volume percentage of 1 to 30% by volume, from which a green body is produced using the mixture obtained in this way, and a ceramic preform is produced by sintering the green body.

Description

Beschreibungdescription
Titeltitle
Keramischer Vorkörper zur Herstellung von Metall-Keramik VerbundwerkstoffenCeramic preform for the production of metal-ceramic composites
Die vorliegende Erfindung betrifft einen Keramischen Vorkörper zur Herstellung von Metall-Keramik Verbundwerkstoffen gemäß dem Oberbegriff des Anspruchs 1.The present invention relates to a ceramic preform for the production of metal-ceramic composite materials according to the preamble of claim 1.
Stand der TechnikState of the art
Steigende Anforderungen an tribologisch (d.h. auf Reibung) belastete Bauteile, insbesondere an die in Fahrzeugen eingesetzten Bremsscheiben, erfordern Werkstoffe mit hoher Korrosions- und Verschleißbeständigkeit, hoher Wärmeleitfähigkeit und hoher mechanischer Festigkeit bis hin zu Temperaturen von 800°C. Übliche Materialien, wie z.B. Grauguss, können diese hohen zukünftigen Anforderungen nicht mehr erfüllen. Ein neuer Material-Ansatz sind Verbundwerkstoffe auf Basis korrosionsbeständiger Metallphasen und temperaturbeständiger und verschleißmindernder Keramikanteilen, insbesondere kupferbasierte Metall-Keramik Verbundwerkstoffe (Metal-Matrix Composites (MMC) oder Ceramic-Matrix Composites (CMC) ) .Increasing demands on tribologically (i.e., on friction) loaded components, in particular on the brake discs used in vehicles require materials with high corrosion and wear resistance, high thermal conductivity and high mechanical strength up to temperatures of 800 ° C. Usual materials, such as Gray cast iron, can no longer meet these high future requirements. A new material approach is composites based on corrosion-resistant metal phases and temperature-resistant and wear-reducing ceramic components, in particular copper-based metal-ceramic composites (MMC) or ceramic-matrix composites (CMC)).
Die Offenlegungsschrift DE 103 50 035 Al beschreibt ein Verfahren zur Herstellung eines Verbundbauteils, vorzugsweise einer Bremsscheibe, welches durch druckunterstütze Infiltration eines keramischen Vorkörpers aus Oxiden, Metallcarbiden oder -nitriden mit einer Schmelze aus Kupferlegierung wie z.B. CuAl, CuMg oder CuSi, hergestellt wird. Hierbei war relevant, dass das dem Kupfer zulegierte Element im Verlauf der Infiltration mit mindestens einer der Keramikphasen reagiert. Die Verwendung einerThe published patent application DE 103 50 035 A1 describes a method for producing a composite component, preferably a brake disk, which is provided by pressure-assisted infiltration of a ceramic preform made of oxides, metal carbides or nitrides with a melt of copper alloy such as CuAl, CuMg or CuSi. It was relevant here that the element alloyed with the copper reacts with at least one of the ceramic phases in the course of the infiltration. The use of a
Kupferlegierung ermöglichte dabei die Anwendung einer gegenüber reinem Kupfer deutlich niedrigeren Schmelztemperatur, während die reaktive Infiltration zu einer Verbesserung der Infiltrierbarkeit führen und gleichzeitig durch das Wegreagieren des Legierungszusatzes die Wärmeleitfähigkeit des Metallanteils im Verbundwerkstoff verbessern sollte.Copper alloy allowed the use of much lower melting temperature than that of pure copper, while reactive infiltration improved the infiltratability while at the same time improving the thermal conductivity of the metal in the composite by dissociating the alloy.
Die angestrebte Reaktion der die Schmelztemperatur herabsetzenden Legierungsbestandteile mit der Keramik und eine dadurch zu erreichende Erhöhung der Temperaturbeständigkeit des Verbundkörpers erweist sich jedoch als schwierig zu bewerkstelligen. Die Reaktion verläuft nur sehr unvollständig, insbesondere bei großvolumigen Bauteilen resultiert daher eine sehr inhomogene Gefügestruktur. Überdies kann eine festigkeitsmindernde Porosität nicht ausgeschlossen werden, da die Volumenanteile der Reaktionsprodukte stets kleiner sind als die der Edukte. Dabei vermindern bereits geringe Restbestandteile an Mischkristallen aus nichtreagierter Cu-Legierung die erforderliche Wärmeleitfähigkeit unzulässig.However, the desired reaction of the melting temperature-reducing alloying constituents with the ceramic and thereby to achieve an increase in the temperature resistance of the composite body proves to be difficult to accomplish. The reaction is very incomplete, therefore, especially in large-volume components results in a very inhomogeneous microstructure. Moreover, a strength-reducing porosity can not be excluded, since the volume fractions of the reaction products are always smaller than those of the educts. Even small residual components of mixed crystals of unreacted Cu alloy reduce the required thermal conductivity inadmissibly.
Hinzu kommt, dass der Vorkörper nur eine relativ geringe Festigkeit aufweist und daher bei der Infiltration nur geringe Drücke angewandt werden können.In addition, the preform has only a relatively low strength and therefore only small pressures can be applied to the infiltration.
Offenbarung der ErfindungDisclosure of the invention
Aufgabe der vorliegenden Erfindung ist es daher, ein Verfahren zur Herstellung eines Vorkörpers zur Herstellung von Metall-Keramik-Verbundwerkstoffen, insbesondere für tribologische Anwendungen, bereit zu stellen, das die Herstellung von Vorkörpern ermöglicht, die eine höhere Festigkeit und eine höhere Thermoschockresistenz aufweisen und so eine Infiltration insbesondere mit hochschmelzenden Metallen oder Metalllegierungen ermöglichen .Object of the present invention is therefore, a A process for producing a preform for the production of metal-ceramic composites, in particular for tribological applications, to provide, which allows the production of precursors, which have a higher strength and a higher thermal shock resistance and thus allow infiltration, in particular with refractory metals or metal alloys ,
Diese Aufgabe wird mit den Merkmalen des vorliegenden Anspruchs 1 gelöst. Die Unteransprüche geben bevorzugte Ausführungsformen an. Dabei ist zu beachten, dass die genannten Bereichsangaben durchweg einschließlich der jeweiligen Grenzwerte zu verstehen sind.This object is achieved with the features of present claim 1. The subclaims indicate preferred embodiments. It should be noted that the specified area information is to be understood throughout including the respective limit values.
Demnach ist ein Verfahren zur Herstellung eines Keramischen Vorkörpers zur Herstellung eines Metall-Keramik- Verbundwerkstoffs, insbesondere für tribologische Anwendungen, wobei einem keramischen Ausgangspulver eine Glasfritte mit im wesentlichen silikatischen und/oder oxidischen Bestandteilen in einem Volumenanteil von 1 bis einschließlich 15 Vol.-% beigegeben wird.Accordingly, a method for producing a ceramic preform for producing a metal-ceramic composite material, in particular for tribological applications, wherein a starting ceramic powder, a glass frit having substantially silicate and / or oxidic constituents in a volume fraction of 1 to 15% by volume inclusive is added.
Unter dem Begriff Glasfritte versteht man ein Zwischenprodukt bei der Herstellung von Glasschmelzen. Die Glasfritte entsteht durch oberflächliches Schmelzen von Glaspulver, wobei die Glaskörner zusammenbacken. Es entsteht ein poröses Material mit einer großen inneren Oberfläche.The term glass frit is understood to mean an intermediate in the production of glass melts. The glass frit is formed by superficial melting of glass powder, whereby the glass grains cake together. The result is a porous material with a large inner surface.
Aus dem auf diese Weise hergestellten Gemisch wird ein Grünkörper hergestellt, und durch Sintern des Grünkörpers wird anschließend ein keramischer Vorkörper hergestellt. Die bevorzugten - A -From the mixture prepared in this way, a green body is produced, and by sintering the green body, a ceramic preform is subsequently produced. The preferred ones - A -
Sintertemperaturen liegen dabei zwischen 1000°C und 1700°C, bevorzugte Sinterzeiten zwischen 1 und 6 Stunden. Die Porosität des Vorkörpers beträgt dabei 20 - 70 Vol.-%, bevorzugt 25 - 60 Vol.-%. Unter Porosität soll das Verhältnis des Volumens aller Hohlräume eines porösen Festkörpers zu dessen äußerem Volumen verstanden werden, wobei die Hohlräume hierbei im Allgemeinen netzwerkartig miteinander verbunden sind und mit der den porösen Festkörper umgebenden Atmosphäre im Austausch stehen bzw. verbunden sind (sogenannte offene Porosität) . Es handelt sich also um ein Maß dafür, wie viel Raum der eigentliche Feststoff innerhalb eines bestimmten Volumens ausfüllt bzw. welche Hohlräume er in diesem hinterlässt. Die Poren sind dabei in der Regel mit Luft gefüllt.Sintering temperatures are between 1000 ° C and 1700 ° C, preferred sintering times between 1 and 6 hours. The porosity of the preform is 20-70% by volume, preferably 25-60% by volume. Porosity is to be understood as meaning the ratio of the volume of all cavities of a porous solid to its outer volume, the cavities being generally networked together and being in exchange or interconnected with the atmosphere surrounding the porous solid (so-called open porosity). It is therefore a measure of how much space the actual solid fills within a certain volume or which cavities it leaves in this volume. The pores are usually filled with air.
Durch die Porosität des Vorkörpers werden daher in der Regel bereits die später zu erwartenden Volumenanteile der Keramik- und der Metallkomponente eines Metall-Keramik-Verbundwerkstoffs festgelegt. Der Porendurchmesser beträgt dabei bevorzugt 0.5 - 10 μm, und besonders bevorzugt 1 - 5 μm.Due to the porosity of the preform, therefore, the volume fractions of the ceramic and metal components of a metal-ceramic composite material which are to be expected later are usually already established. The pore diameter is preferably 0.5-10 μm, and more preferably 1-5 μm.
Der Volumenanteil der Glasfritte beträgt besonders bevorzugt 2 - 8 Vol.-%. Die Glasfritte besteht erfindungsgemäß aus silikatischen und/oder oxidischen Bestandteilen. Diese Bestandteile werden so ausgewählt, dass die Glasfritte ein Erweichungsintervall aufweist, das unterhalb der ursprünglichen Sintertemperatur von 1000°C bis 1700°C liegt.The volume fraction of the glass frit is particularly preferably 2-8 vol .-%. The glass frit according to the invention consists of silicate and / or oxidic constituents. These ingredients are selected such that the glass frit has a softening interval that is below the original sintering temperature of 1000 ° C to 1700 ° C.
Durch die erfindungsgemäße Hinzufügung der Glasfritte zum keramischen Ausgangspulver kann die Sintertemperatur im Vergleich zu Grünkörpern ohne Glasfritte herabgesetzt werden, da sich beim Sintern Sinterhälse aus Glasmaterial ausbilden. Da die Glasfritte bei den eingestellten Sintertemperaturen erweicht, findet überdies anteilig ein Flüssigphasensintern statt.By adding the glass frit according to the invention to the ceramic starting powder, the sintering temperature can be reduced in comparison to green bodies without glass frit, since sintered necks of glass material form during sintering. Because the glass frit softened at the set sintering temperatures, moreover, there is a proportionate liquid phase sintering.
Beides führt zu einer Reduktion der Sinterschwindung bei hohen Temperaturen, so dass der Grünkörper bereits endkonturnah gefertigt werden kann. Zudem weist der erhaltene keramische Körper eine erhöhte Hochtemperatur-Festigkeit und Thermoschockresistenz auf, was sich insbesondere im Verlauf der der Infiltration vorgeschalteten Vorwärmprozedur des keramischen Vorkörpers sowie auch der Infiltration mit hochschmelzenden Metallen bzw. Metalllegierungen positiv auswirkt.Both lead to a reduction of the sintering shrinkage at high temperatures, so that the green body can already be produced close to final contour. In addition, the resulting ceramic body has an increased high-temperature strength and thermal shock resistance, which has a positive effect in particular in the course of the preheating procedure of the ceramic preform preceding the infiltration as well as the infiltration with refractory metals or metal alloys.
In einer bevorzugten Ausgestaltung des erfindungsgemäßen Verfahrens werden dem keramischen Ausgangspulver keramische Fasern in einem Volumenanteil von 1 bis 60 Vol.-%, und/oder Porenbildner in einem Volumenanteil von 1 bis 30 Vol.-% hinzugegeben .In a preferred embodiment of the method according to the invention ceramic fibers in a volume fraction of 1 to 60 vol .-%, and / or pore forming agent in a volume fraction of 1 to 30 vol .-% are added to the ceramic starting powder.
Die keramischen Fasern erhöhen nicht nur die mechanische Belastbarkeit, insbesondere die mechanische Hochtemperatur- Belastbarkeit, des Metall-Keramik Verbundwerkstoffs, sondern auch die des keramischen Vorkörpers vor der Infiltration erheblich. Letzteres wirkt sich wiederum positiv auf die Vorkörperstabilität im Verlauf der Infiltration aus . Bei den keramischen Fasern handelt es sich um metallische oder keramische Fasern, bevorzugt um oxidkeramische Fasern, besonders bevorzugt um Fasern, die im wesentlichen aus AI2O3 bestehen. Es kann sich dabei um kontinuierliche oder Kurzfasern mit einem Durchmesser von ca. 2 μm bis 20 μm handeln. Diese werden dem keramischen Ausgangspulver bevorzugt in einem Volumenanteil von 10 - 50 Vol.-% hinzugegeben. Diese Fasern können lose in das Ausgangspulver gegeben werden, oder aber in Form eines Inserts aus gewobenen, kontinuierlichen Al2O3-Fasern .The ceramic fibers not only significantly increase the mechanical strength, in particular the high-temperature mechanical strength, of the metal-ceramic composite, but also that of the ceramic preform prior to infiltration. The latter in turn has a positive effect on the precursor stability in the course of the infiltration. The ceramic fibers are metallic or ceramic fibers, preferably oxide-ceramic fibers, more preferably fibers consisting essentially of Al 2 O 3 . It may be continuous or short fibers with a diameter of about 2 microns to 20 microns. These are preferably added to the starting ceramic powder in a volume fraction of 10 to 50% by volume. These fibers can be added loosely to the starting powder, or in the form of an insert of woven continuous Al 2 O 3 fibers.
Bei den Porenbildnern handelt es sich um längliche, leicht ausbrennbare Stoffe, die während des Sinterns verbrennen und so ein Netzwerk von Kanälen und Poren erzeugen, das die anschließende Infiltration der Metallschmelze erleichtert und eine innige Verbindung zwischen dem Vorkörper und dem erstarrenden Metall ermöglicht. Die auf diese Weise erzeugten Kanäle können Breiten von 2 - 50 μm, bevorzugt 5 - 30 μm aufweisen. Durch die die Kanäle im fertigen Körper ausfüllenden Metallkanäle wird die Festigkeit und Zähigkeit der Körper weiter erhöht .The pore builders are elongated, easily burnable substances that burn during sintering, creating a network of channels and pores that facilitate subsequent infiltration of the molten metal and allow intimate bonding between the preform and the solidifying metal. The channels produced in this way can have widths of 2 to 50 μm, preferably 5 to 30 μm. By the channels filling in the finished body metal channels, the strength and toughness of the body is further increased.
Die Porenbildner haben - neben den eingestellten Sinterparametern - einen wesentlichen Einfluss auf die Einstellung einer bestimmten Porosität. Porenbildner können aber auch insbesondere bei der Herstellung keramischer Vorkörper verwendet werden, um ein Netzwerk von Porenkanälen zu erzeugen, die eine bessere Infiltrierbarkeit des Vorkörpers zur Folge haben; die Porenkanäle fungieren hier als Infiltrationskanäle. Zudem werden durch die so entstandenen Metallkanäle Festigkeit und Zähigkeit des Werkstoffes erhöht, und es wird eine große innere Oberfläche geschaffen, die Raum bietet für Reaktionen zwischen dem Keramikmaterial des Vorkörpers und der Metallphase.The pore formers have - besides the set sintering parameters - a significant influence on the setting of a certain porosity. However, pore formers can also be used in particular in the production of ceramic preforms in order to produce a network of pore channels, which result in a better infiltrability of the preform; the pore channels act as infiltration channels here. In addition, the resulting metal channels increase the strength and toughness of the material, and create a large internal surface that provides space for reactions between the ceramic material of the preform and the metal phase.
Besonders bevorzugt werden hier Zelluloseplättchen oder -fasern mit einem Volumenanteil von 1 - 30 %, bevorzugt 2 - 20 % verwendet. Weiterhin sind als Porenbildner z.B. auch Rußpartikel, Reisstärke oder organische Makromoleküle, wie z.B. Fullerene oder Nanotubes denkbar. Im Wesentlichen eignen sich als Porenbildner all solche Materialien, die während des Sinterns verbrennen, zerfallen oder ausgasen und auf diese Weise Hohlräume in dem Material erzeugen.Cellulose flakes or fibers having a volume fraction of 1 to 30%, preferably 2 to 20%, are particularly preferably used here. Also suitable as pore formers are, for example, soot particles, rice starch or organic macromolecules, such as, for example, fullerenes or nanotubes. In essence, pore formers are all those materials that burn during sintering, disintegrate or outgas, thus creating voids in the material.
Im Übrigen sind auch Stoffe denkbar, die beim Sintern Gas freisetzen und so eine Porenbildung hervorrufen. Hier käme z.B. NaHCC>3 in Frage, das unter Hitze CO2 freisetzt.Incidentally, substances are also conceivable which release gas during sintering and thus cause pore formation. Here would come, for example NaHCC> 3, which releases CO2 under heat.
Besonders bevorzugt handelt es sich bei dem keramischen Ausgangsmaterial um ein oder mehrere Materialien ausgewählt aus der Gruppe bestehend aus Oxiden, Carbiden, Nitriden, Boriden und/oder Silikaten.Particularly preferably, the ceramic starting material is one or more materials selected from the group consisting of oxides, carbides, nitrides, borides and / or silicates.
Hier kommen insbesondere Oxide, wie z.B. AI2O3 oder Tiθ2, Karbide wie z.B. SiC, oder Nitride wie z.B. Si3N4 oder AlN, bzw. Gemische der vorgenannten Stoffe in Frage.In particular, oxides such as e.g. Al 2 O 3 or TiO 2, carbides, e.g. SiC, or nitrides, e.g. Si3N4 or AlN, or mixtures of the aforementioned substances in question.
Weiterhin ist erfindungsgemäß ein keramischer Vorkörper zur Herstellung eines Metall-Keramik-Verbundwerkstoffs vorgesehen, der gemäß einem der vorherigen Verfahren hergestellt wird. Der Vorkörper weist ein Porengefüge mit einer Gesamtporosität von 20 - 70 Vol.-%, bevorzugt 25 - 60 Vol.-% auf. Die Poren weisen Durchmesser zwischen 0.5 und 10 μm, bevorzugt 1 - 5 μm auf.Furthermore, according to the invention, a ceramic preform is provided for producing a metal-ceramic composite material which is produced according to one of the preceding methods. The preform has a pore structure with a total porosity of 20-70% by volume, preferably 25-60% by volume. The pores have diameters between 0.5 and 10 .mu.m, preferably 1-5 .mu.m.
Ebenso ist erfindungsgemäß ein Verfahren zur Herstellung eines Metall-Keramik-Verbundwerkstoff aus einem Vorkörper gemäß einem der vorherigen Ansprüche vorgesehen, wobei der Vorkörper mit einer Schmelze aus Metall oder einer Metalllegierung infiltriert wird.Likewise, a method for producing a metal-ceramic composite material from a preform according to one of the preceding claims is provided according to the invention, wherein the preform is infiltrated with a melt of metal or a metal alloy.
Bevorzugt kommen hierbei hochschmelzende Metalle bzw. hochschmelzende Metalllegierungen zum Einsatz, wie z.B. Kupfer oder Kupferlegierungen. Durch Verwendung einer hochschmelzenden Metallphase wird gegenüber niedrigschmelzenden Metallphasen - z.B. aluminiumbasierten Legierungen - eine deutlich höhere Einsatztemperatur der Metall-Keramik-Verbundwerkstoffe ermöglicht. Die erfindungsgemäßen Werkstoffe sind daher z.B. als Friktionswerkstoffe wie Bremsenmaterialien für ein sehr viel breiteres Einsatzspektrum verwendbar.Preference is given here to refractory metals or high-melting metal alloys are used, such as copper or copper alloys. By using a refractory metal phase is compared to low-melting metal phases - eg aluminum-based alloys - a significantly higher operating temperature of metal-ceramic composites possible. The materials according to the invention can therefore be used, for example, as friction materials such as brake materials for a much wider range of applications.
Hingegen sind z.B. Metall-Keramik-Verbundwerkstoffe, die auf niedriger schmelzenden Metallphasen wie Aluminium-Gusslegierungen basieren, für einen Einsatz als hochbelastete Friktionswerkstoffe nicht denkbar. Beispielsweise sind bei Bremsscheiben in schweren und leistungsstarken Fahrzeugen, also insbesondere Mittel- und Oberklassefahrzeugen, SUV, Vans und Sportwagen, hoheOn the other hand, e.g. Metal-ceramic composites based on lower melting metal phases, such as cast aluminum alloys, are unimaginable for use as highly stressed friction materials. For example, in brake discs in heavy and powerful vehicles, so in particular middle and luxury vehicles, SUVs, vans and sports cars, high
Bremsscheibentemperaturen von teilweise über 600°C zu erwarten, was über der Schmelztemperatur der gebräuchlichen Aluminium- Gusslegierungen liegt.Brake disc temperatures of more than 600 ° C to expect, which is above the melting temperature of the common aluminum casting alloys.
Der mit dem erfindungsgemäßen Verfahren hergestellte keramische Vorkörper weist eine Gefügestruktur und Zusammensetzung auf, die eine Infiltration mit einem hochschmelzenden Metall bzw. einer hochschmelzenden Metalllegierung, z.B. reinen Kupfer, begünstigt bzw. erst ermöglicht.The ceramic preform produced by the method of the present invention has a microstructure and composition involving infiltration with a refractory metal or refractory metal alloy, e.g. pure copper, favors or only allows.
Zugleich wird durch das erfindungsgemäße Verfahren eine Verbesserung des anwendungsspezifischen Eigenschaftsprofils erreicht. Hierbei wird insbesondere berücksichtigt, dass die keramischen Vorkörper den im Infiltrationsprozess erforderlichen hohen Drücken und hohen Temperaturen standhalten müssen. Durch die erfindungsgemäß erzielbare definierte Porenstruktur des Vorkörpers wird überdies die Schmelzinfiltration unterstützt. Im Ergebnis wird eine hohe Infiltrationsqualität erzielt, die zu Metall-Keramik-Verbundwerkstoffen mit geringer bis nicht vorhandener Restporosität führt. Zudem können auch geringere Infiltrationsdrucke angewandt werden.At the same time an improvement of the application-specific property profile is achieved by the inventive method. In this case, it is particularly taken into account that the ceramic preforms have to withstand the high pressures and high temperatures required in the infiltration process. Moreover, the inventively achievable defined pore structure of the preform supports melt infiltration. As a result, a high infiltration quality is achieved resulting in metal-ceramic composites with little to no residual porosity. In addition, lower infiltration pressures can also be used.
Weiterhin ist bevorzugt vorgesehen, dass der Vorkörper zuvor auf eine Temperatur nahe der Schmelztemperatur des Metalls oder der Metalllegierung gebracht wurde (Infiltrationsschritt) .Furthermore, it is preferably provided that the preform has previously been brought to a temperature close to the melting temperature of the metal or the metal alloy (infiltration step).
Dies dient zur Vermeidung von Thermoschocks und einem vorzeitigen Erstarren der Metallschmelze in der Infiltrationsfront. Dabei sollte die Temperaturdifferenz nicht größer als 350°C, bevorzugt nicht größer als 100°C sein. Dies kann beispielsweise durch ein Vorwärmen des Vorkörpers vor der Infiltration gewährleistet werden .This is to avoid thermal shock and premature solidification of the molten metal in the infiltration front. In this case, the temperature difference should not be greater than 350 ° C, preferably not greater than 100 ° C. This can be ensured, for example, by preheating the preform prior to infiltration.
Eine zusätzliche Maßnahme kann darin bestehen, den vorgewärmten keramischen Vorkörper mit einer isolierenden Umhüllung zu umgeben, z.B. mit Keramikpapier oder -Vlies.An additional measure may be to surround the preheated ceramic preform with an insulating sheath, e.g. with ceramic paper or fleece.
Die Infiltration mit Metallschmelze erfolgt dabei bevorzugt reaktionsunterstützt, d.h. es findet bei geeigneter Wahl der Keramik- und Metallphase eine auf die Oberflächenzone derThe infiltration with molten metal is preferably reaction-assisted, i. it finds a suitable choice of ceramic and metal phase on the surface zone of the
Keramikphase beschränkte Reaktion mit der Metallphase statt. Hierbei kann neben dem Hauptbestandteil der Metallphase auch ein Legierungselemnt in Verbindung mit keramischen Anteilen reaktiv sein. Durch eine Oberflächenreaktion der Keramikphase kann die Infiltrationsqualität verbessert und der Infiltrationsdruck erniedrigt werden. Ursache hierfür ist die freigesetzte Reaktionswärme bzw. die veränderte Oberflächenspannung aufgrund der neu gebildeten Grenzflächenphase.Ceramic phase limited reaction with the metal phase instead. In this case, in addition to the main constituent of the metal phase, an alloying element may also be reactive in connection with ceramic fractions. By a surface reaction of the ceramic phase, the quality of infiltration can be improved and the infiltration pressure can be lowered. The reason for this is the released Reaction heat or the changed surface tension due to the newly formed interface phase.
Weiterhin ist bevorzugt vorgesehen, dass die Schmelze aus Metall oder einer Metalllegierung unter Aufwendung eines äußeren Druckes infiltriert wird. Als mögliche Verfahren kommen hier insbesondere Gasdruckinfiltration oder Schmelzinfiltration mittels der bekannten Technik des „Squeeze Casting" in Frage. Bei der Metalllegierung handelt es sich bevorzugt um Kupfer bzw. eine Kupferlegierung ausgewählt aus der Gruppe enthaltend Cu-ETP, CuMgx, CuAlx, CuSix, CuZrx, CuTix, CuZnx und/oder CuAlxFeγNiz .Furthermore, it is preferably provided that the melt of metal or a metal alloy is infiltrated by applying an external pressure. As a possible method, in particular gas pressure infiltration or melt-infiltration come here means of the known technique of "squeeze casting" in question. In the metal alloy it is preferably copper or a copper alloy selected from the group consisting of Cu-ETP, CuMg x, CuAl x, CuSi x , CuZr x , CuTi x , CuZn x and / or CuAl x Fe γ Ni z .
Weiterhin ist ein Metall-Keramik-Verbundwerkstoff vorgesehen, der mit einem Verfahren gemäß einem der vorherigen Ansprüche hergestellt wurde.Furthermore, a metal-ceramic composite material is provided, which was produced by a method according to one of the preceding claims.
Beispielexample
Das erfindungsgemäße Verfahren soll im Folgenden anhand eines Beispiels dargestellt werden. Dabei ist zu beachten, dass das Beispiel in keiner Weise den Schutzbereich der vorliegenden Erfindung einschränken soll.The method according to the invention will be illustrated below by way of example. It should be noted that the example is in no way intended to limit the scope of the present invention.
Es wurden keramische Vorkörper aus einem keramischen Ausgangspulver hergestellt, welches aus 60 Vol.-% Tiθ2,Ceramic preforms were produced from a ceramic starting powder, which consists of 60% by volume of TiO 2,
23 Vol.-% Al2O3-Kurzfasern und 7 Vol.-% Cellulose bestand. Dem Ausgangspulver wurden 10 Vol.-% einer Glasfritte mit im Wesentlichen silikatischen und oxidischen Bestandteilen hinzugefügt. Nach definiertem Pressen und Sintern ergaben sich keramische Vorkörper mit 50% Porosität, die anschließend mit reiner Kupferschmelze bei 1200°C infiltriert wurden. Die Ausprägung der Infiltrationskanäle durch die ausgebrannten Celluloseplättchen ermöglichte dabei eine vollständige und reproduzierbar homogene Kupferinfiltration. Die Keramikfasern erhöhten die Hochtemperaturfestigkeit der Keramik-Vorkörper und ermöglichten somit eine druckunterstützte Schmelzinfiltration ohne Rissbildung im keramischen Vorkörper.23 vol.% Al 2 O 3 short fibers and 7 vol.% Cellulose. To the starting powder was added 10% by volume of a glass frit having substantially siliceous and oxidic components. After defined pressing and sintering, ceramic preforms with 50% porosity were obtained, which were then infiltrated with pure copper melt at 1200 ° C. The expression of the infiltration channels by the burnt out Cellulose platelets allowed a complete and reproducible homogeneous copper infiltration. The ceramic fibers increased the high-temperature strength of the ceramic preforms and thus enabled pressure-assisted melt infiltration without cracking in the ceramic preform.
Durch die Hinzufügung der Glasfritte wird, wie oben beschrieben, die Sintertemperatur im Vergleich zu Grünkörpern ohne Glasfritte herabgesetzt, da sich beim Sintern Sinterhälse aus Glasmaterial ausbilden. Da die Glasfritte bei den eingestellten Sintertemperaturen erweicht, findet anteilig ein Flüssigphasensintern statt. Im Ergebnis kommt es zu einer Reduktion der Sinterschwindung bei hohen Temperaturen, wie sie z.B. beim Vorwärmen des Vorkörpers vor der Infiltration bzw. während der Infiltration auftreten, was zu einer Verbesserung der Prozessstabilität führt. Auch zeigen solchermaßen prozessierte Verbundwerkstoffe eine höhere Festigkeit und eine höhere Thermoschockresistenz .The addition of the glass frit, as described above, the sintering temperature is reduced compared to green bodies without glass frit, as formed during sintering sintered necks of glass material. Since the glass frit softens at the set sintering temperatures, a proportionate liquid phase sintering takes place. As a result, there is a reduction in sintering shrinkage at high temperatures, e.g. occur during preheating of the preform prior to infiltration or during infiltration, resulting in an improvement in process stability. Also, such processed composite materials show higher strength and higher thermal shock resistance.
Das in Fig. 1 dargestellte Schliffbild eines mit dem erfindungsgemäßen Verfahren hergestellten Körpers aus Metall- Keramik-Verbundwerkstoff zeigt die erhaltene Gefügestruktur: The micrograph of a metal-ceramic composite body produced by the method according to the invention shown in FIG. 1 shows the resulting microstructure:

Claims

Ansprüche : Claims :
1. Verfahren zur Herstellung eines Keramischen Vorkörpers zur Herstellung eines Metall-Keramik Verbundwerkstoffs, insbesondere für tribologische Anwendungen, wobei einem keramischen Ausgangspulver1. A process for producing a ceramic preform body for producing a metal-ceramic composite material, in particular for tribological applications, wherein a ceramic starting powder
a) eine Glasfritte mit im wesentlichen silikatischen und/oder oxidischen Bestandteilen in einem Volumenanteil von 1 bis 15 Vol.-% und/odera) a glass frit having substantially silicate and / or oxidic constituents in a volume fraction of 1 to 15% by volume and / or
beigegeben wird,is added,
b) aus dem auf diese Weise hergestellten Gemisch ein Grünkörper hergestellt wird, und c) durch Sintern des Grünkörpers ein keramischer Vorkörper hergestellt wird.b) a green body is produced from the mixture produced in this way, and c) a ceramic preform is produced by sintering the green body.
2. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, dass dem keramischen Ausgangspulver weiterhin2. The method according to claim 1, characterized in that the ceramic starting powder continue
d) keramische Fasern in einem Volumenanteil von 1 bis 60 Vol.-%, und/oder e) Porenbildner in einem Volumenanteil von 1 bis 30 Vol.-%d) ceramic fibers in a volume fraction of 1 to 60% by volume, and / or e) pore formers in a volume fraction of 1 to 30% by volume
beigegeben werden.be added.
3. Verfahren gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, dass dem sich bei dem keramischen Ausgangsmaterial um ein oder mehrere Materialien ausgewählt aus der Gruppe bestehend aus Oxiden, Carbiden, Nitriden, Boriden und/oder Silikaten handelt .3. The method according to claim 1 or 2, characterized in that in the ceramic starting material to a or more materials selected from the group consisting of oxides, carbides, nitrides, borides and / or silicates.
4. Keramischer Vorkörper zur Herstellung eines Metall-Keramik- Verbundwerkstoffs, der gemäß einem der vorherigen Verfahren hergestellt wird, aufweisend4. A ceramic preform for producing a metal-ceramic composite produced according to one of the preceding methods, comprising
a) ein Porengefüge mit einer Gesamtporosität von 20 bis 70 Vol.-%, b) wobei die Poren Durchmesser zwischen 0.5 und 10 μm aufweisen .a) a pore structure with a total porosity of 20 to 70 vol .-%, b) wherein the pores have diameters between 0.5 and 10 microns.
5. Verfahren zur Herstellung eines Metall-Keramik- Verbundwerkstoff aus einem Vorkörper gemäß Anspruch 3, wobei der Vorkörpers mit einer Schmelze aus Metall oder einer Metalllegierung infiltriert wird5. A method for producing a metal-ceramic composite material from a preform according to claim 3, wherein the preform is infiltrated with a melt of metal or a metal alloy
6. Verfahren gemäß Anspruch 5, dadurch gekennzeichnet, dass der Vorkörper zuvor auf eine Temperatur nahe der6. The method according to claim 5, characterized in that the preform previously to a temperature close to
Schmelztemperatur des Metalls oder der Metalllegierung gebracht wurde (Infiltrationsschritt).Melting temperature of the metal or metal alloy was brought (infiltration step).
7. Verfahren gemäß einem der Ansprüche 5 - 6, dadurch gekennzeichnet, dass die Schmelze aus Metall oder einer Metalllegierung unter Aufwendung eines äußeren Druckes infiltriert wird.7. The method according to any one of claims 5-6, characterized in that the melt of metal or a metal alloy is infiltrated by applying an external pressure.
8. Verfahren gemäß einem der Ansprüche 5 - 7, dadurch gekennzeichnet, dass es sich bei dem Metall bzw. der8. The method according to any one of claims 5-7, characterized in that it is in the metal or the
Metalllegierung um Kupfer bzw. eine Kupferlegierung ausgewählt aus der Gruppe enthaltend Cu-ETP, CuMgx, CuAlx, CuSix, CuZrx, CuTix, CuZnx und/oder CuAlxFeYNiz handelt.Metal alloy around copper or a copper alloy selected from the group consisting of Cu-ETP, CuMg x , CuAl x , CuSi x , CuZr x , CuTi x , CuZn x and / or CuAl x Fe Y Ni z is.
9. Metall-Keramik-Verbundwerkstoff, hergestellt mit einem Verfahren gemäß einem der Ansprüche 5 - 8.9. metal-ceramic composite material, produced by a method according to any one of claims 5-8.
10. Bauteil für tribologische Anwendungen, insbesondere im Fahrzeugbau, aufweisend einen Metall-Keramik-Verbundwerkstoff gemäß Anspruch 9.10. Component for tribological applications, in particular in vehicle construction, comprising a metal-ceramic composite material according to claim 9.
11. Metall-Keramik-Verbundwerkstoff bzw. Bauteil für tribologische Anwendungen aus einem Metall-Keramik- Verbundwerkstoff, dadurch gekennzeichnet, dass dieser bzw. dieses Glasbestandteile aufweist, die aus der Verwendung einer Glasfritte bei der Herstellung desselben herrühren. 11. A metal-ceramic composite component for tribological applications of a metal-ceramic composite, characterized in that it comprises glass components resulting from the use of a glass frit in the manufacture thereof.
PCT/EP2007/064070 2007-01-19 2007-12-17 Ceramic preform for the production of metal-ceramic composite materials WO2008086930A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007002833.6 2007-01-19
DE102007002833A DE102007002833A1 (en) 2007-01-19 2007-01-19 Ceramic preform for the production of metal-ceramic composites

Publications (1)

Publication Number Publication Date
WO2008086930A1 true WO2008086930A1 (en) 2008-07-24

Family

ID=39135296

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2007/064070 WO2008086930A1 (en) 2007-01-19 2007-12-17 Ceramic preform for the production of metal-ceramic composite materials

Country Status (2)

Country Link
DE (1) DE102007002833A1 (en)
WO (1) WO2008086930A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021004325A1 (en) 2021-08-24 2023-03-02 HiPer Medical AG Multiphase ceramic-ceramic composite and method of making same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2225060A2 (en) * 2007-12-21 2010-09-08 CeramTec AG Method for producing preforms for metal-matrix composites

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4409298A (en) * 1982-07-21 1983-10-11 Borg-Warner Corporation Castable metal composite friction materials
JPH0382724A (en) * 1989-08-25 1991-04-08 Suzuki Motor Corp Manufacture of preform of metal matrix composite
JP2000204454A (en) * 1999-01-14 2000-07-25 Nichias Corp Preform for metal matrix composite material and its production
JP2000234157A (en) * 1999-02-10 2000-08-29 Nichias Corp Preform for metal matrix composite material and its production
EP1059133A1 (en) * 1999-06-11 2000-12-13 Nichias Corporation Preform for metal matrix composite material and cylinder block made of the same
JP2001003146A (en) * 1999-06-22 2001-01-09 Nichias Corp Reform for metal matrix composite material and its production
EP1433553A1 (en) * 2002-12-20 2004-06-30 Ceramtec AG Composite material and method for its manufacture
EP1510720A2 (en) * 2003-08-27 2005-03-02 Robert Bosch Gmbh Method for producing a brake disc and brake disc
WO2005042439A1 (en) * 2003-10-27 2005-05-12 Robert Bosch Gmbh Method for producing a composite part and metal/ceramic part
EP1538134A1 (en) * 2003-12-04 2005-06-08 Ceramtec AG Porous Fibre-Ceramic-Composite Material

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4409298A (en) * 1982-07-21 1983-10-11 Borg-Warner Corporation Castable metal composite friction materials
JPH0382724A (en) * 1989-08-25 1991-04-08 Suzuki Motor Corp Manufacture of preform of metal matrix composite
JP2000204454A (en) * 1999-01-14 2000-07-25 Nichias Corp Preform for metal matrix composite material and its production
JP2000234157A (en) * 1999-02-10 2000-08-29 Nichias Corp Preform for metal matrix composite material and its production
EP1059133A1 (en) * 1999-06-11 2000-12-13 Nichias Corporation Preform for metal matrix composite material and cylinder block made of the same
JP2001003146A (en) * 1999-06-22 2001-01-09 Nichias Corp Reform for metal matrix composite material and its production
EP1433553A1 (en) * 2002-12-20 2004-06-30 Ceramtec AG Composite material and method for its manufacture
EP1510720A2 (en) * 2003-08-27 2005-03-02 Robert Bosch Gmbh Method for producing a brake disc and brake disc
WO2005042439A1 (en) * 2003-10-27 2005-05-12 Robert Bosch Gmbh Method for producing a composite part and metal/ceramic part
EP1538134A1 (en) * 2003-12-04 2005-06-08 Ceramtec AG Porous Fibre-Ceramic-Composite Material

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021004325A1 (en) 2021-08-24 2023-03-02 HiPer Medical AG Multiphase ceramic-ceramic composite and method of making same

Also Published As

Publication number Publication date
DE102007002833A1 (en) 2008-07-24

Similar Documents

Publication Publication Date Title
DE10203285C1 (en) Sinterable powder mixture for the production of sintered components
DE3914010C2 (en) Process for the production of metal-ceramic composites and use of the process for controlling the material properties of composites
DE3817350C2 (en)
WO2008052833A1 (en) Material for tribological applications
EP1685081B1 (en) Method for producing a composite part and metal/ceramic part
WO2014114714A1 (en) Method for producing spray powders containing chromium nitride
DE102006051200A1 (en) Method for producing a body from metal-ceramic composite materials
DE102011012142B3 (en) Aluminum matrix composite, semi-finished aluminum matrix composite material and process for its production
DE19752776C1 (en) Production of metal-ceramic composite parts, e.g. brake discs
EP3150304A1 (en) Method for the production of a valve seat insert
EP3027341A1 (en) Insert part that can be infiltrated
EP1433553B1 (en) Method for manufacture of composite material
WO2008086930A1 (en) Ceramic preform for the production of metal-ceramic composite materials
EP1390321B1 (en) Metal-ceramic composite material and method for production thereof
DE102009050025A1 (en) Ceramic brake disk for use in high speed brake system, has friction layers made of silicon and silicon carbide, where part of silicon carbide and/or carbon components of layers and/or carrier body is encapsulated in envelope
DE102006040120B3 (en) Composite materials comprise ceramic or carbon fibers with a metal coating which are embedded in metal matrix whose melting point is lower than that of coating
DE102004002714B3 (en) To produce sintered components, of light metal alloys, the powder is compressed into a green compact to be give a low temperature sintering followed by further compression and high temperature sintering
EP1560799A2 (en) Ceramic-metal or metal-ceramic composite
EP1525330A1 (en) Method for producing a component, component and use thereof
DE102005029039B4 (en) Production process for mold with non-stick coating
DE10354655A1 (en) Composite component is formed by placing a reactive material powder in a mould, pressing, sintering, and infiltration with a metal melt
DE10222788B4 (en) Method for producing a ceramic material with an at least substantially oxide-ceramic matrix and pores embedded therein
DE19750600A1 (en) New constructional element consists of a magnesium-infiltrated porous metal reinforcing element body
DE10117394A1 (en) Metal-ceramic brake disk used for brakes comprises a matrix made from column and/or crystal-like silicon nitride infiltrated with an aluminum alloy in a squeeze-casting method
DE10045049A1 (en) Process for the production of metal-ceramic brake discs

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07857700

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 07857700

Country of ref document: EP

Kind code of ref document: A1