WO2004035309A1 - Composite metal/ceramic product having surface compressive stresses - Google Patents

Composite metal/ceramic product having surface compressive stresses Download PDF

Info

Publication number
WO2004035309A1
WO2004035309A1 PCT/EP2003/011374 EP0311374W WO2004035309A1 WO 2004035309 A1 WO2004035309 A1 WO 2004035309A1 EP 0311374 W EP0311374 W EP 0311374W WO 2004035309 A1 WO2004035309 A1 WO 2004035309A1
Authority
WO
WIPO (PCT)
Prior art keywords
layers
composite product
volume
product according
metal
Prior art date
Application number
PCT/EP2003/011374
Other languages
German (de)
French (fr)
Inventor
Sven Scheppokat
Rolf Janssen
Nils Claussen
Original Assignee
Tuhh-Technonologie Gmbh
Technische Universität Hamburg-Harburg
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 Tuhh-Technonologie Gmbh, Technische Universität Hamburg-Harburg filed Critical Tuhh-Technonologie Gmbh
Priority to AU2003274003A priority Critical patent/AU2003274003A1/en
Publication of WO2004035309A1 publication Critical patent/WO2004035309A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • 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
    • B22F7/02—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 composite layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B18/00—Layered products essentially comprising ceramics, e.g. refractory products
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C24/00—Coating starting from inorganic powder
    • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/02—Pretreatment of the material to be coated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/10—Oxidising
    • 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
    • B22F2998/10—Processes characterised by the sequence of their steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/658—Atmosphere during thermal treatment
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/66—Specific sintering techniques, e.g. centrifugal sintering
    • C04B2235/668—Pressureless sintering
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
    • 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
    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
    • C04B2237/32—Ceramic
    • C04B2237/34—Oxidic
    • C04B2237/343—Alumina or aluminates
    • 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
    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
    • C04B2237/58—Forming a gradient in composition or in properties across the laminate or the joined articles
    • C04B2237/582—Forming a gradient in composition or in properties across the laminate or the joined articles by joining layers or articles of the same composition but having different additives
    • 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
    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
    • C04B2237/70—Forming laminates or joined articles comprising layers of a specific, unusual thickness
    • C04B2237/704—Forming laminates or joined articles comprising layers of a specific, unusual thickness of one or more of the ceramic layers or articles

Definitions

  • the invention relates to a metal / ceramic composite product made of powder metallurgy, reactive sintered metal / ceramic composite materials in which compressive stresses are generated in the surface and its production.
  • Surface compressive stresses are suitable for significantly increasing the damage tolerance of components. This is an effective method, particularly with brittle materials such as ceramics, to increase the reliability and service life of components, especially under operating conditions in which surface damage can be expected. Otherwise damage to the surface of ceramic components can be drastically reduced or even catastrophic failure of the entire component can result. This can largely be avoided by surface compressive stresses. Surface compressive stresses are multifunctional; in addition to an increase in damage tolerance, higher strength and improved wear resistance are also to be expected. The principle is universally applicable; possible applications are e.g. Rolling bearings, engine parts and hydraulic components.
  • surface compressive stresses can be generated in components in various ways, e.g. by applying an outer layer with a lower coefficient of thermal expansion on a material with a higher coefficient of expansion. If the material is plastically deformable at high temperature, it is then stress-free at high temperature (typically> 1000 ° C for ceramics) due to plastic deformation. When it cools, the plasticity disappears and forms compressive stresses in the surface area.
  • systems with surface compressive stresses for example in the case of glass, are already state of the art and are used in a variety of ways (safety glass).
  • the invention has for its object to produce a metal / ceramic composite product with surface tensions, which reach deep into the material in a controlled manner, so that crack growth is reliably hindered and layer detachments are avoided.
  • a metal / ceramic composite product with surface tensions which is characterized by the structure of several layers with different expansion coefficients of the adjacent layers, the layers containing Al 2 O 3 and up to 70% by volume of at least one metal ,
  • the metal portion of the layers preferably consists of at least one of the metals Cr, Fe, Mo, Al, aluminide, Al alloys of Cr, Fe or Mo or mixtures thereof.
  • such a composite product can advantageously still contain up to 80% by volume of ZrO 2 .
  • the properties of the composite product can also be regulated by adding carbides and / or nitrides, these being present in an amount of 1 to 20% by volume.
  • the carbides or nitrides are preferably selected from Cr 3 C 2 , SiC, TiC, B 4 C, TaC and BN.
  • the outer layer of a composite product according to the invention can have a lower metal content than the underlying layer, here referred to as substrate, or a metal with a lower thermal expansion coefficient than the substrate, which consequently contains a higher metal content or / and one metal or more metals with a higher thermal expansion coefficient.
  • the outer layer of the composite products according to the invention is generally harder than the inner layer or. the interior of the material in a two-layer construction. A proportion of metals that form alloys with one another results in good interfacial strength.
  • a composite product according to the invention can be produced by several processes.
  • a densely sintered s-3A composite material as is known from EP 0 902 771, is made of 2 to 70% by volume Cr, 0.1 to 20% by volume Al and up to 80 vol .-% ZrO 2 consists of, annealed in an oxygen-containing atmosphere until the Cr is oxidized in the surface layer.
  • the Al 2 O 3 / Cr 2 O 3 mixed crystals have a lower thermal expansion coefficient than pure Al 2 O 3 .
  • 5 to 60 is preferred Annealed in air at a temperature of 1000 to 1500 ° C for minutes. However, the annealing treatment can also be extended to several hours.
  • heat treatment can also be carried out in a vacuum or under protective gas in order to bring about structural changes without changing the composition of the layers of the composite product itself.
  • powder layers with different compositions are produced dry or wet by powder metallurgy and densely sintered in an inert atmosphere.
  • different powder mixtures are pressed sequentially and then sintered as described.
  • this procedure can also be carried out by immersing a green body made of a material with a higher coefficient of thermal expansion, for example Fe / Al / Al 2 O 3 , into a suspension of a metal with a lower coefficient of expansion such as Cr / Al / Al 2 O 3 , so that a coating of the green body is achieved (dip coating).
  • the material is then densely sintered.
  • the coefficient of thermal expansion can be adjusted by adding ZrO 2 , carbides and / or nitrides in different amounts as described above.
  • this procedure uses an inner layer composed of 35 to 40% by weight of Fe, 2.5 to 3.5% by weight of Al and 57 to 59% by weight of Al 2 O 3 with the composition 37 to 38 wt .-% Cr, 0.5 to 1 wt .-% Al and 61, 5 to 62.5 wt .-% Al 2 O 3 coated, this being done dry or wet powder metallurgy can.
  • the coated body is then densely sintered at at least 1450 ° C.
  • a composite product according to the invention can be produced in two layers by the above methods, so that an inner body is completely covered with an outer layer.
  • the layers can also be built up so that e.g. further layers with different coefficients of expansion are applied to a plate of an inner layer with a certain composition on one or both sides and then densely sintered in an inert atmosphere.
  • the cover layers in turn have different compositions in order to be able to correspond in a special way to the intended later use.
  • a multiplicity of layers can also be provided, the only important thing is that each layer differs from the other layer. a n l i e g e n s e ch i c hte n i m expansion coefficient.
  • the starting materials were used in the form of fine powders produced in attritor mills, which were produced by the process of EP 0 902 771 (s-3A process).
  • the process is based on the aluminothermic reduction of metal oxides or oxide layers.
  • powder mixtures of Al 2 O 3 , a metal (for example Cr, Fe, Mo) and aluminum are ground intensively, compacted by pressure and densely sintered in a vacuum or protective gas.
  • ZrO 2 is often added to improve the mechanical properties.
  • the aluminum serves to reduce the oxide layer on the particles of the other metal and thus to achieve a higher sintering activity.
  • pressure-assisted sintering processes are usually used Compaction must be used, the s-3A process allows an unpressurized and therefore much cheaper sintering.
  • 0.35 g of a powder mixture of 37.20% by weight of Cr, 0.75% by weight of Al and 62.06% by weight of Al 2 O 3 were placed in a press die of the base area 4.3 mm ⁇ 47 mm and lightly pressed with approx. 5 N. Subsequently, 3.3 g of a powder mixture of 38.26% by weight of Fe, 3.82% by weight of Al and 57.92% by weight of Al 2 O 3 were added to the first layer contained in the press die and mixed with approx. 5 N lightly pressed.
  • a third layer was then placed on the two layers in the press mold, the quantity and composition of which was identical to the first layer, so that a symmetrical three-layer composite was formed, which was then uniaxially with a pressure of 50 MPa and then isostatically with a pressure of 900 MPa and then densely sintered at 1,500 ° C in argon.
  • the resulting samples showed no delamination of the layers and consisted of a central inner layer about 6 mm thick with two outer layers each about 0.6 mm thick.
  • Bending rods produced in this way in which a Vickers impression was made in the surface layer with a load of up to 294 N, showed a significantly higher residual strength compared to samples not constructed in layers and a reduced crack growth around the Vickers impression perpendicular to the longitudinal axis of the bending rod.
  • the first was placed in the die Layer 2.5 g of a powder mixture of 25.09 wt .-% Fe, 2.51 wt .-% Al, 20.09 wt .-% ZrO 2 and 52.31 wt .-% Al 2 O 3 and with approx. 5 N lightly pressed.
  • a third layer was then placed on the two layers in the press mold, the quantity and composition of which was identical to the first layer, so that a symmetrical three-layer composite was formed, which was then uniaxially with a pressure of 50 MPa and then isostatically with a pressure of 900 MPa and then densely sintered at 1,500 ° C in argon.
  • the resulting samples showed no delamination of the layers and consisted of a central inner layer about 5 mm thick with two outer layers each about 0.5 mm thick.
  • a composite material already sintered to a density of approx. 96% of the theoretical density, produced from a powder mixture of 28.71% by weight Cr, 0.57% by weight Al, 1 9.62% by weight ZrO 2 and 51.1% by weight Al 2 0 3 was annealed in air at a temperature of 1,500 ° C. for 30 minutes.
  • the glow in air caused an oxidation of Cr in the edge area of the sample and an approximately 600 ⁇ m thick edge layer was formed, in which microscopic Cr could no longer be detected.
  • a Vickers impression introduced into this boundary layer with a load of 98.1 N showed no cracks.
  • a composite material already sintered to a density of approx. 97% of the theoretical density, produced from a powder mixture of 1 6.60% by weight Cr, 0.33% by weight Al and 83.07% by weight Al 2 O. 3 was annealed in air at a temperature of 1,500 ° C for 15 minutes.
  • the glow in air caused an oxidation of Cr in the edge area of the sample and an approx. 300 ⁇ m thick edge layer was formed, in which microscopic Cr could no longer be detected.
  • One in this Edge layer with a load of 98.1 N introduced Vickers impression showed no cracks in contrast to the otherwise usual behavior of brittle materials.

Abstract

Disclosed is a composite metal/ceramic product which has surface compressive stresses and is provided with a structure comprising several layers, neighboring layers having different expansion coefficients. Said layers contain Al2O3 and up to 70 percent by volume of at least one metal. The inventive composite metal/ceramic product can be obtained by producing in a dry or wet powder-metallurgical manner layers of powder having a different composition and dense sintering said layers in an inert atmosphere.

Description

METALL/KERAMIK- VERBUND PRODUKT MIT OBERFLÄCHENDRUCKSPANNUNGEN METAL / CERAMIC COMPOSITE PRODUCT WITH SURFACE PRESSURE TENSIONS
Beschreibungdescription
Die Erfindung betrifft ein Metall/Keramik-Verbundprodukt aus pulvermetallurgisch hergestellten, reaktiv gesinterten Metall/Keramik- Verbundwerkstoffen, bei denen Druckspannungen in der Oberfläche erzeugt sind und dessen Herstellung.The invention relates to a metal / ceramic composite product made of powder metallurgy, reactive sintered metal / ceramic composite materials in which compressive stresses are generated in the surface and its production.
Oberflächendruckspannungen sind geeignet, die Schadenstoleranz von Bauteilen deutlich zu steigern. Dies ist insbesondere bei spröden Werkstoffen wie Keramiken eine wirkungsvolle Methode, die Zuverlässigkeit und Lebensdauer von Bauteilen zu erhöhen, speziell unter Einsatzbedingungen, bei denen mit einer Oberflächenschädigung zu rechnen ist. Durch eine Oberflächenschädigung kann ansonsten bei Keramikbauteilen die Festigkeit drastisch vermindert oder sogar ein katastrophales Versagen des gesamten Bauteils herbeigeführt werden. Durch Oberflächendruckspannungen lässt sich dieses weitgehend vermeiden. Oberflächendruckspannungen sind dabei multifunktional; neben einer Erhöhung der Schadenstoleranz ist dabei auch eine höhere Festigkeit und eine verbesserte Verschleissfestigkeit zu erwarten. Das Prinzip ist universell anwendbar; mögliche Anwendungen sind z.B. Wälzlager, Motorteile und Hydraulikkomponenten.Surface compressive stresses are suitable for significantly increasing the damage tolerance of components. This is an effective method, particularly with brittle materials such as ceramics, to increase the reliability and service life of components, especially under operating conditions in which surface damage can be expected. Otherwise damage to the surface of ceramic components can be drastically reduced or even catastrophic failure of the entire component can result. This can largely be avoided by surface compressive stresses. Surface compressive stresses are multifunctional; in addition to an increase in damage tolerance, higher strength and improved wear resistance are also to be expected. The principle is universally applicable; possible applications are e.g. Rolling bearings, engine parts and hydraulic components.
Prinzipiell lassen sich in Bauteilen Oberflächendruckspannungen auf verschiedene Weise erzeugen, z.b. durch Aufbringen einer Außenschicht mit niedrigerem thermischen Ausdehnungskoeffizienten auf einem Material mit höherem Ausdehnungskoffizienten. Sofern das Material bei hoher Temperatur plastisch verformbar ist, ist es bei hoher Temperatur (bei Keramik typisch > 1000 °C) dann durch plastische Verformung spannungsfrei, beim Abkühlen verschwindet die Plastizität und es bilden sich Druckspannungen im Oberflächenbereich. Grundsätzlich sind Systeme mit Oberflächendruckspannungen z.B. bei Glas bereits Stand der Technik und werden vielfältig genutzt (Sicherheitsglas) .In principle, surface compressive stresses can be generated in components in various ways, e.g. by applying an outer layer with a lower coefficient of thermal expansion on a material with a higher coefficient of expansion. If the material is plastically deformable at high temperature, it is then stress-free at high temperature (typically> 1000 ° C for ceramics) due to plastic deformation. When it cools, the plasticity disappears and forms compressive stresses in the surface area. In principle, systems with surface compressive stresses, for example in the case of glass, are already state of the art and are used in a variety of ways (safety glass).
Sofern bei Keramiken Oberflächendruckspannungen erzeugt werden, geschieht dies durch eine Oberflächenbehandlung (z.B. Schleifen) . Die dadurch erzeugten Spannungen reichen jedoch nicht tief genug in das Material (einige 10 μm), um bei einer Oberflächenschädigung ein Wachsen des Risses in die zwangsläufig (Kräftegleichgewicht) unter einer Druckspannungszone befindliche Zugspannungszone zu verhindern. Die Herstellung von Schichtverbunden mit Druckspannungen aus konventionellen Keramikwerkstoffen scheitert bisher an der mangelnden plastischen Verformbarkeit des Materials sowie an einer nicht ausreichenden Festigkeit der Grenzflächen zwischen den verschiedenen Materialien, die zu einer Ablösung der Schichten führt.If surface compressive stresses are generated in ceramics, this is done by surface treatment (e.g. grinding). However, the stresses generated in this way do not reach deep enough in the material (a few 10 μm) to prevent the crack from growing into the tensile stress zone which is inevitably (balance of forces) under a compressive stress zone if the surface is damaged. The production of layer composites with compressive stresses from conventional ceramic materials has so far failed due to the lack of plastic deformability of the material and the insufficient strength of the interfaces between the different materials, which leads to the layers becoming detached.
Der Erfindung liegt die Aufgabe zugrunde ein Metall/Keramik- Verbundprodukt mit Oberflächenspannungen zu erzeugen, welche in geregelter Weise tief in das Material hineinreichen, sodass ein Risswachstum zuverlässig behindert wird und Schichtenablösungen vermieden werden. Insbesondere ist es ein Ziel der Erfindung durch Reaktionssintern hergestellte Materialien wie sie in EP 0 902 771 und DE 44 47 1 30 beschrieben sind und als s-3A-Produkte (sintered alumina aluminide alloys) bezeichnet werden hinsichtlich der Materialeigenschaften wesentlich zu verbessern.The invention has for its object to produce a metal / ceramic composite product with surface tensions, which reach deep into the material in a controlled manner, so that crack growth is reliably hindered and layer detachments are avoided. In particular, it is an object of the invention to improve materials produced by reaction sintering as described in EP 0 902 771 and DE 44 47 1 30 and referred to as s-3A products (sintered alumina aluminide alloys).
Erfindungsgemäß wird dies erreicht durch ein Metall/Keramik- Verbundprodukt mit Oberflächenspannungen, welches durch den Aufbau aus mehreren Schichten mit unterschiedlichem Ausdehnungskoeffizienten der benachbarten Schichten, wobei die Schichten AI2O3 und bis zu 70 Vol.- % mindestens eines Metalls enthalten, gekennzeichnet ist. Bevorzugt besteht der Metallanteil der Schichten aus mindestens einem der Metalle Cr, Fe, Mo, AI, Aluminid, AI-Legierungen von Cr, Fe oder Mo oder Mischungen davon. Zusätzlich kann ein derartiges Verbundprodukt vorteilhaft noch bis zu 80 Vol.-% ZrO2 enthalten.According to the invention this is achieved by a metal / ceramic composite product with surface tensions, which is characterized by the structure of several layers with different expansion coefficients of the adjacent layers, the layers containing Al 2 O 3 and up to 70% by volume of at least one metal , The metal portion of the layers preferably consists of at least one of the metals Cr, Fe, Mo, Al, aluminide, Al alloys of Cr, Fe or Mo or mixtures thereof. In addition, such a composite product can advantageously still contain up to 80% by volume of ZrO 2 .
Die Eigenschaften des Verbundproduktes lassen sich weiterhin durch einen Zusatz von Carbiden oder/und Nitriden regeln, wobei diese in einer Menge von 1 bis 20 Vol.-% vorliegen können. Bevorzugt werden die Carbide bzw. Nitride ausgewählt unter Cr3C2, SiC, TiC, B4C, TaC und BN.The properties of the composite product can also be regulated by adding carbides and / or nitrides, these being present in an amount of 1 to 20% by volume. The carbides or nitrides are preferably selected from Cr 3 C 2 , SiC, TiC, B 4 C, TaC and BN.
Die Außenschicht eines erfindungsgemäßen Verbundproduktes kann einen geringeren Metallanteil als die darunterliegende, hier als Substrat bezeichnete Schicht oder ein Metall mit niedrigerem thermischen Ausdehnungskoeffizienten als das Substrat aufweisen, welches demzufolge einen höheren Metallanteil oder/und ein Metall oder mehrere Metalle mit höherem thermischen Ausdehnungskoeffizienten enthält. Die Außenschicht der erfindungsgemäßen Verbundprodukte ist in der Regel härter als die I nnensch icht bzw . das I nnere des Materials bei einem Zweischichtenaufbau. Ein Anteil an Metallen, die miteinander Legierungen bilden, ergibt eine gute Grenzflächenfestigkeit.The outer layer of a composite product according to the invention can have a lower metal content than the underlying layer, here referred to as substrate, or a metal with a lower thermal expansion coefficient than the substrate, which consequently contains a higher metal content or / and one metal or more metals with a higher thermal expansion coefficient. The outer layer of the composite products according to the invention is generally harder than the inner layer or. the interior of the material in a two-layer construction. A proportion of metals that form alloys with one another results in good interfacial strength.
Die Herstellung eines erfindungsgemäßen Verbundproduktes kann im Prinzip nach mehreren Verfahren erfolgen. Gemäß einer bevorzugten Ausführungsform des Herstellungsverfahrens wird ein dicht gesinterter s- 3A-Verbundwerkstoff, wie er aus EP 0 902 771 bekannt ist, der aus 2 bis 70 Vol.-% Cr, 0, 1 bis 20 Vol.-% AI und bis zu 80 Vol.-% ZrO2 besteht, in sauerstoffhaltiger Atmosphäre geglüht bis das Cr in der Oberflächenschicht oxidiert ist. Dabei entsteht Cr2O3, welches mit AI2O3 eine lückenlose Mischkristallreihe bildet. Die AI2O3/Cr2O3-Mischkristalle besitzen einen niedrigeren thermischen Ausdehnungskoeffizienten als reines AI2O3. Beim Abkühlen des Produktes entstehen daher in der Außenschicht Druckspannungen. Vorzugsweise wird bei dieser Verfahrensart 5 bis 60 Minuten bei einer Temperatur von 1000 bis 1 500 °C an der Luft geglüht. Die Glühbehandlung kann jedoch auch bis auf mehrere Stunden ausgedehnt werden.In principle, a composite product according to the invention can be produced by several processes. According to a preferred embodiment of the production process, a densely sintered s-3A composite material, as is known from EP 0 902 771, is made of 2 to 70% by volume Cr, 0.1 to 20% by volume Al and up to 80 vol .-% ZrO 2 consists of, annealed in an oxygen-containing atmosphere until the Cr is oxidized in the surface layer. This produces Cr 2 O 3 , which forms a complete mixed crystal row with Al 2 O 3 . The Al 2 O 3 / Cr 2 O 3 mixed crystals have a lower thermal expansion coefficient than pure Al 2 O 3 . When the product cools down, compressive stresses develop in the outer layer. In this type of process, 5 to 60 is preferred Annealed in air at a temperature of 1000 to 1500 ° C for minutes. However, the annealing treatment can also be extended to several hours.
Im Anschluss an die Glühbehandlung an Luft kann auch eine Wärmebehandlung im Vakuum oder unter Schutzgas erfolgen, um Strukturänderungen herbeizuführen ohne dabei auch die Zusammensetzung der Schichten des Verbundproduktes an sich zu ändern.Following the annealing treatment in air, heat treatment can also be carried out in a vacuum or under protective gas in order to bring about structural changes without changing the composition of the layers of the composite product itself.
Gemäß einer weiteren Ausführungsforms des erfindungsgemäßen Verfahrens werden Pu lversc h ichten mit u ntersch iedlicher Zusammensetzung trocken oder nass pulvermetallurgisch hergestellt und in inerter Atmosphäre dicht gesintert. Typischerweise werden dabei verschiedene Pulvermischungen sequenziell verpresst und anschließend wie beschrieben gesintert. Diese Verfahrensweise lässt sich aber auch so durchführen, dass ein Grünkörper aus einem Material mit höherem thermischen Ausdehnungskoeffizienten, beispielsweise Fe/AI/AI2O3, in eine Suspension eines Metalls mit niedrigerem Ausdehnungskoeffizienten wie z.B. Cr/AI/AI2O3 getaucht werden, sodass eine Beschichtung des Grünkörpers erzielt wird (dip coating) . Anschließend wird das Material dicht gesintert. Neben Cr und Fe eignen sich dazu auch die anderen oben schon erwähnten Metalle wie insbesondere Mo, Nb und Ta. Ferner kann der thermische Ausdehnungskoeffizient durch Zusatz von ZrO2, Carbiden oder/und Nitriden in unterschiedlichen Mengen wie oben schon beschrieben, eingestellt werden.According to a further embodiment of the method according to the invention, powder layers with different compositions are produced dry or wet by powder metallurgy and densely sintered in an inert atmosphere. Typically, different powder mixtures are pressed sequentially and then sintered as described. However, this procedure can also be carried out by immersing a green body made of a material with a higher coefficient of thermal expansion, for example Fe / Al / Al 2 O 3 , into a suspension of a metal with a lower coefficient of expansion such as Cr / Al / Al 2 O 3 , so that a coating of the green body is achieved (dip coating). The material is then densely sintered. In addition to Cr and Fe, the other metals already mentioned above, such as in particular Mo, Nb and Ta, are also suitable for this purpose. Furthermore, the coefficient of thermal expansion can be adjusted by adding ZrO 2 , carbides and / or nitrides in different amounts as described above.
Bei dieser Verfahrensweise wird gemäß einer besonders bevorzugten Ausführungsform eine Innenschicht aus 35 bis 40 Gew.-% Fe, 2,5 bis 3,5 Gew.-% AI und 57 bis 59 Gew.-% AI2O3 mit der Zusammensetzung 37 bis 38 Gew.-% Cr, 0,5 bis 1 Gew.-% AI und 61 ,5 bis 62,5 Gew.-% AI2O3 beschichtet, wobei dies trocken oder nass pulvermetallurgisch erfolgen kann. Der beschichtete Körper wird dann bei mindestens 1450 °C dicht gesintert.According to a particularly preferred embodiment, this procedure uses an inner layer composed of 35 to 40% by weight of Fe, 2.5 to 3.5% by weight of Al and 57 to 59% by weight of Al 2 O 3 with the composition 37 to 38 wt .-% Cr, 0.5 to 1 wt .-% Al and 61, 5 to 62.5 wt .-% Al 2 O 3 coated, this being done dry or wet powder metallurgy can. The coated body is then densely sintered at at least 1450 ° C.
Ein erfindungsgemäßes Verbundprodukt kann nach den obigen Verfahren zweischichtig hergestellt werden, sodass ein Innenkörper vollständig mit einer Außenschicht bedeckt ist. Der Schichtenaufbau kann aber auch so erfolgen, dass z.B. auf eine Platte einer Innenschicht mit bestimmter Zusammensetzung auf einer oder beiden Seiten weitere Schichten mit unterschiedlichem Ausdehnungskoeffizienten aufgebracht und dann in inerter Atmosphäre dicht gesintert werden. Dabei können z.B. die Deckschichten ihrerseits unterschiedliche Zusammensetzung aufweisen, um dem beabsichtigten späteren Verwendungszweck in besonderer Weise entsprechen zu können. Es können auch eine Vielzahl von Schichten vorgesehen werden, wesentlich ist lediglich, dass jede Schicht sich von der a n l ieg e n d e n S c h i c ht b z w . a n l i e g e n d e n Sc h i c hte n i m Ausdehnungskoeffizienten unterscheidet.A composite product according to the invention can be produced in two layers by the above methods, so that an inner body is completely covered with an outer layer. The layers can also be built up so that e.g. further layers with different coefficients of expansion are applied to a plate of an inner layer with a certain composition on one or both sides and then densely sintered in an inert atmosphere. Here, e.g. the cover layers in turn have different compositions in order to be able to correspond in a special way to the intended later use. A multiplicity of layers can also be provided, the only important thing is that each layer differs from the other layer. a n l i e g e n s e ch i c hte n i m expansion coefficient.
Die folgenden Beispiele erläutern die Erfindung weiter. Die Ausgangsmaterialien wurden hierbei jeweils in Form von in Attritormühlen hergestellten feinen Pulvern eingesetzt, die nach dem Verfahren des EP 0 902 771 hergestellt waren (s-3A-Verfahren). Das Verfahren beruht auf der aluminothermischen Reduktion von Metalloxiden bzw. Oxidschichten. Bei der in den Beispielen angewendeten Variante des Verfahrens werden Pulvermischungen aus AI2O3, einem Metall (z.B. Cr, Fe, Mo) und Aluminium intensiv vermählen, durch Druck kompaktiert und in Vakuum oder Schutzgas dichtgesintert. Zur Verbesserung der mechanischen Eigenschaften wird oftmals ZrO2 zugegeben. Dabei dient das Aluminium dazu, die auf den Partikeln des anderen Metalls befindliche Oxidschicht zu reduzieren und so eine höhere Sinteraktivität zu erzielen. Während bei nicht reaktiver pulvermetallurgischer Herstellung von Metall/Keramik- Verbundwerkstoffen üblicherweise druckunterstützte Sinterverfahren zur Verdichtung eingesetzt werden müssen, gestattet das s-3A-Verfahren eine drucklose und damit wesentlich kostengünstigere Sinterung.The following examples further illustrate the invention. The starting materials were used in the form of fine powders produced in attritor mills, which were produced by the process of EP 0 902 771 (s-3A process). The process is based on the aluminothermic reduction of metal oxides or oxide layers. In the variant of the method used in the examples, powder mixtures of Al 2 O 3 , a metal (for example Cr, Fe, Mo) and aluminum are ground intensively, compacted by pressure and densely sintered in a vacuum or protective gas. ZrO 2 is often added to improve the mechanical properties. The aluminum serves to reduce the oxide layer on the particles of the other metal and thus to achieve a higher sintering activity. While in non-reactive powder metallurgical production of metal / ceramic composites, pressure-assisted sintering processes are usually used Compaction must be used, the s-3A process allows an unpressurized and therefore much cheaper sintering.
BeispieleExamples
Beispiel 1example 1
In eine Pressmatrize der Grundfläche 4,3 mm x 47 mm wurden 0,35 g einer Pulvermischung aus 37,20 Gew.-% Cr, 0,75 Gew.-% AI und 62,06 Gew.-% AI2O3 gegeben und mit ca. 5 N leicht angepresst. Anschließend wurden in die Pressmatrize auf die darin befindliche erste Schicht 3,3 g einer Pulvermischung aus 38,26 Gew.-% Fe, 3,82 Gew.-% AI und 57,92 Gew.-% AI2O3 gegeben und mit ca. 5 N leicht angepresst. Daraufhin wurde auf die beiden in der Pressform befindlichen Schichten eine dritte Schicht gegeben, die in ihrer Menge und Zusammensetzung identisch mit der ersten Schicht war, sodass ein symmetrischer Dreischichtverbund entstand, der dann zunächst uniaxial mit einem Druck von 50 MPa und anschließend isostatisch mit einem Druck von 900 MPa verpresst und anschließend bei 1 500 °C in Argon dichtgesintert wurde. Die entstehenden Proben zeigten keine Delamination der Schichten und bestanden aus einer zentralen ca. 6 mm dicken inneren Schicht mit zwei Randschichten von je ca. 0,6 mm Dicke. Auf diese Weise hergestellte Biegestäbchen, bei denen in die Randschicht mit einer Last von bis zu 294 N ein Vickerseindruck eingebracht wurde, zeigten im Vergleich zu nicht schichtartig aufgebauten Proben eine deutlich höhere Restfestigkeit sowie ein reduziertes Risswachstum um den Vickerseindruck senkrecht zur Längsachse des Biegestäbchens.0.35 g of a powder mixture of 37.20% by weight of Cr, 0.75% by weight of Al and 62.06% by weight of Al 2 O 3 were placed in a press die of the base area 4.3 mm × 47 mm and lightly pressed with approx. 5 N. Subsequently, 3.3 g of a powder mixture of 38.26% by weight of Fe, 3.82% by weight of Al and 57.92% by weight of Al 2 O 3 were added to the first layer contained in the press die and mixed with approx. 5 N lightly pressed. A third layer was then placed on the two layers in the press mold, the quantity and composition of which was identical to the first layer, so that a symmetrical three-layer composite was formed, which was then uniaxially with a pressure of 50 MPa and then isostatically with a pressure of 900 MPa and then densely sintered at 1,500 ° C in argon. The resulting samples showed no delamination of the layers and consisted of a central inner layer about 6 mm thick with two outer layers each about 0.6 mm thick. Bending rods produced in this way, in which a Vickers impression was made in the surface layer with a load of up to 294 N, showed a significantly higher residual strength compared to samples not constructed in layers and a reduced crack growth around the Vickers impression perpendicular to the longitudinal axis of the bending rod.
Beispiel 2Example 2
In eine Pressmatrize der Grundfläche 4,3 mm x 47 mm wurden 0,4 g einer Pulvermischung aus 28,71 Gew.-% Cr, 0,57 Gew.-% AI, 1 9,62 Gew.-%0.4 g of a powder mixture of 28.71% by weight Cr, 0.57% by weight Al, 1 9.62% by weight were placed in a press die with a base area of 4.3 mm × 47 mm.
ZrO2 und 51 , 1 0 Gew.-% AI2O3 gegeben und mit ca. 5 N leicht angepresst.ZrO 2 and 51, 1 0 wt .-% Al 2 O 3 and slightly pressed with about 5 N.
Anschließend wurden in die Pressmatrize auf die darin befindliche erste Schicht 2,5 g einer Pulvermischung aus 25,09 Gew.-% Fe, 2,51 Gew.-% AI, 20,09 Gew.-% ZrO2 und 52,31 Gew.-% AI2O3 gegeben und mit ca. 5 N leicht angepresst. Daraufhin wurde auf die beiden in der Pressform befindlichen Schichten eine dritte Schicht gegeben, die in ihrer Menge und Zusammensetzung identisch mit der ersten Schicht war, sodass ein symmetrischer Dreischichtverbund entstand, der dann zunächst uniaxial mit einem Druck von 50 MPa und anschließend isostatisch mit einem Druck von 900 MPa verpresst und anschließend bei 1 500 °C in Argon dichtgesintert wurde. Die entstehenden Proben zeigten keine Delamination der Schichten und bestanden aus einer zentralen ca. 5 mm dicken inneren Schicht mit zwei Randschichten von je ca. 0,5 mm Dicke.Then the first was placed in the die Layer 2.5 g of a powder mixture of 25.09 wt .-% Fe, 2.51 wt .-% Al, 20.09 wt .-% ZrO 2 and 52.31 wt .-% Al 2 O 3 and with approx. 5 N lightly pressed. A third layer was then placed on the two layers in the press mold, the quantity and composition of which was identical to the first layer, so that a symmetrical three-layer composite was formed, which was then uniaxially with a pressure of 50 MPa and then isostatically with a pressure of 900 MPa and then densely sintered at 1,500 ° C in argon. The resulting samples showed no delamination of the layers and consisted of a central inner layer about 5 mm thick with two outer layers each about 0.5 mm thick.
Beispiel 3Example 3
Ein bereits auf eine Dichte von ca. 96 % der theoretischen Dichte gesinterter Verbundwerkstoff, hergestellt aus einer Pulvermischung aus 28,71 Gew.-% Cr, 0,57 Gew. -% AI, 1 9,62 Gew. -% ZrO2 und 51 , 1 0 Gew. - % Al203, wurde bei einer Temperatur von 1 500 °C für 30 Minuten an Luft geglüht. Durch das Glühen an Luft kam es zu einer Oxidation von Cr im Randbereich der Probe und es bildete sich eine ca. 600 μm dicke Randschicht, in der mikroskopisch kein metallisches Cr mehr nachweisbar war. Ein in diese Randschicht mit einer Last von 98, 1 N eingebrachter Vickerseindruck zeigte im Gegensatz zum sonst üblichen Verhalten spröder Werkstoffe keine Risse.A composite material already sintered to a density of approx. 96% of the theoretical density, produced from a powder mixture of 28.71% by weight Cr, 0.57% by weight Al, 1 9.62% by weight ZrO 2 and 51.1% by weight Al 2 0 3 was annealed in air at a temperature of 1,500 ° C. for 30 minutes. The glow in air caused an oxidation of Cr in the edge area of the sample and an approximately 600 μm thick edge layer was formed, in which microscopic Cr could no longer be detected. In contrast to the otherwise usual behavior of brittle materials, a Vickers impression introduced into this boundary layer with a load of 98.1 N showed no cracks.
Beispiel 4Example 4
Ein bereits auf eine Dichte von ca. 97 % der theoretischen Dichte gesinterter Verbundwerkstoff, hergestellt aus einer Pulvermischung aus 1 6,60 Gew.-% Cr, 0,33 Gew.-% AI und 83,07 Gew.-% AI2O3 wurde bei einer Temperatur von 1 500 °C für 1 5 Minuten an Luft geglüht. Durch das Glühen an Luft kam es zu einer Oxidation von Cr im Randbereich der Probe und es bildete sich eine ca. 300 μm dicke Randschicht, in der mikroskopisch kein metallisches Cr mehr nachweisbar war. Ein in diese Randschicht mit einer Last von 98, 1 N eingebrachter Vickerseindruck zeigte im Gegensatz zum sonst üblichen Verhalten spröder Werkstoffe keine Risse. A composite material already sintered to a density of approx. 97% of the theoretical density, produced from a powder mixture of 1 6.60% by weight Cr, 0.33% by weight Al and 83.07% by weight Al 2 O. 3 was annealed in air at a temperature of 1,500 ° C for 15 minutes. The glow in air caused an oxidation of Cr in the edge area of the sample and an approx. 300 μm thick edge layer was formed, in which microscopic Cr could no longer be detected. One in this Edge layer with a load of 98.1 N introduced Vickers impression showed no cracks in contrast to the otherwise usual behavior of brittle materials.

Claims

Ansprüche Expectations
1. Metall/Keramik-Verbundprodukt mit Oberflächendruckspannungen, g e ke n n ze i c h n et d u rc h den Aufbau aus mehreren Schichten mit unterschiedlichem Ausdehnungskoeffizienten der benachbarten Schichten, wobei die Schichten AI2O3 und bis zu 70 Vol.-% mindestens eines Metalls enthalten.1. Metal / ceramic composite product with surface compressive stresses, ge ke nn ze ichn et du rc h the structure of several layers with different expansion coefficients of the adjacent layers, the layers containing Al 2 O 3 and up to 70 vol .-% of at least one metal ,
2. Verbundprodukt nach Anspruch 1, d a d u rc h g e ke n n z e i c h n et, dass der Metallanteil der Schichten aus mindestens einem der Metalle Cr, Fe, Mo, AI, Aluminid, AI-Legierungen von Cr, Fe oder Mo oder Mischungen davon besteht.2. Composite product according to claim 1, so that the metal portion of the layers consists of at least one of the metals Cr, Fe, Mo, Al, aluminide, Al alloys of Cr, Fe or Mo or mixtures thereof.
3. Verbundprodukt nach Anspruch 1 oder 2, d a d u rc h g e ke n n ze ic h n et, dass es zusätzlich bis 80 Vol.-% ZrO2 enthält.3. Composite product according to claim 1 or 2, so that it additionally contains up to 80% by volume of ZrO 2 .
4. Verbundprodukt nach Anspruch 1, 2 oder 3, d a d u r c h g e ke n n ze ic h n et, dass es zusätzlich 1 bis 20 Vol.-% Carbide oder Nitride enthält.4. Composite product according to claim 1, 2 or 3, so that it additionally contains 1 to 20% by volume of carbides or nitrides.
5. Verbundprodukt nach Anspruch 4, d ad u rc h g e ken n ze ic h n et, dass die Carbide oder Nitride ausgewählt sind unter Cr3C2, SiC, TiC,5. Composite product according to claim 4, so that the carbides or nitrides are selected from Cr 3 C 2 , SiC, TiC,
B4C, TaC und BN.B 4 C, TaC and BN.
6. Verfahren zur Herstellung eines Verbundproduktes nach einem der Ansprüche 1 bis 5, d a d u r c h g e ke n n z e i c h n et , dass ein dicht gesinterter s-3A-Verbundwerkstoff aus AI2O3 mit 2 bis 70 Vol.-% Cr, 0,1 bis 20 Vol.-% AI und bis 80 Vol.-% ZrO in sauerstoffhaltiger Atmosphäre geglüht wird, bis das Cr in der Oberflächenschicht oxidiert ist.6. A method for producing a composite product according to one of claims 1 to 5, dadurchge ke nnzeichn et, that a densely sintered s-3A composite material made of Al 2 O 3 with 2 to 70% by volume Cr, 0.1 to 20% by volume Al and up to 80% by volume ZrO is annealed in an oxygen-containing atmosphere until the Cr is oxidized in the surface layer.
7. Verfahren nach Anspruch 6, d a d u rc h g e k e n n ze i c h n et , dass 5 bis 60 Minuten bei 1000 bis 1500 °C geglüht wird.7. The method of claim 6, d a d u rc h g e k e n n ze i c h n et that is annealed at 1000 to 1500 ° C for 5 to 60 minutes.
8. Verfahren zur Herstellung eines Verbundprodukts nach einem der8. A method for producing a composite product according to one of the
Ansprüche 1 bis 5, d a d u rc h g e ke n n ze i c h n et, dass Pulverschichten mit unterschiedlicher Zusammensetzung trocken oder nass pulvermetallurgisch hergestellt und in inerter Atmosphäre dichtgesintert werden.Claims 1 to 5, namely that powder layers with different compositions are produced dry or wet by powder metallurgy and densely sintered in an inert atmosphere.
9. Verfahren nach Anspruch 8, d a d u r c h g e k e n n z e i c h n e t , dass in den Pulverschichten enthaltene Metalle miteinander Legierungen bilden.9. The method according to claim 8, so that the metals contained in the powder layers form alloys with one another.
10. Verfahren nach Anspruch 8 oder 9, d a d u rc h g e ke n n ze i c h n et , dass eine Innenschicht aus 35 bis 40 Gew.-% Fe, 2,5 bis 3,5 Gew.- % AI und 57 bis 59 Gew.-% AI2O3 mit Schichten der10. The method of claim 8 or 9, so that an inner layer of 35 to 40 wt .-% Fe, 2.5 to 3.5 wt .-% Al and 57 to 59 wt .-% % AI 2 O 3 with layers of
Zusammensetzung 37 bis 38 Gew.-% Cr, 0,5 bis 1 Gew.-% AI und 61,5 bis 62,5 Gew.-% AI2O3 trocken oder nass pulvermetallurgisch hergestellt und bei mindestens 1450 °C dichtgesintert werden. Composition 37 to 38 wt .-% Cr, 0.5 to 1 wt .-% Al and 61.5 to 62.5 wt .-% Al 2 O 3 dry or wet powder metallurgy and densely sintered at at least 1450 ° C.
PCT/EP2003/011374 2002-10-14 2003-10-14 Composite metal/ceramic product having surface compressive stresses WO2004035309A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003274003A AU2003274003A1 (en) 2002-10-14 2003-10-14 Composite metal/ceramic product having surface compressive stresses

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10247807.4 2002-10-14
DE2002147807 DE10247807A1 (en) 2002-10-14 2002-10-14 Metal/ceramic composite product with surface strains used in the production of engine parts and hydraulic components comprises a structure composed of several layers with different expansion coefficients

Publications (1)

Publication Number Publication Date
WO2004035309A1 true WO2004035309A1 (en) 2004-04-29

Family

ID=32038638

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2003/011374 WO2004035309A1 (en) 2002-10-14 2003-10-14 Composite metal/ceramic product having surface compressive stresses

Country Status (3)

Country Link
AU (1) AU2003274003A1 (en)
DE (1) DE10247807A1 (en)
WO (1) WO2004035309A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113061793A (en) * 2021-02-26 2021-07-02 成都虹波实业股份有限公司 Refractory metal-based high-volume-ratio ceramic material and preparation process thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB788918A (en) * 1953-06-09 1958-01-08 Union Carbide Corp Laminated ceramic articles and slip casting method of producing the same
US4602956A (en) * 1984-12-17 1986-07-29 North American Philips Lighting Corporation Cermet composites, process for producing them and arc tube incorporating them
US4659547A (en) * 1984-05-24 1987-04-21 Hoganas Ab Inhomogeneous sintered body
DE4119705A1 (en) * 1991-06-14 1992-12-17 Claussen Nils Ceramic composite body with metallic components - comprising wear resistant gas tight outer ceramic layer, inner structure of cement and intermediate layer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB788918A (en) * 1953-06-09 1958-01-08 Union Carbide Corp Laminated ceramic articles and slip casting method of producing the same
US4659547A (en) * 1984-05-24 1987-04-21 Hoganas Ab Inhomogeneous sintered body
US4602956A (en) * 1984-12-17 1986-07-29 North American Philips Lighting Corporation Cermet composites, process for producing them and arc tube incorporating them
DE4119705A1 (en) * 1991-06-14 1992-12-17 Claussen Nils Ceramic composite body with metallic components - comprising wear resistant gas tight outer ceramic layer, inner structure of cement and intermediate layer

Also Published As

Publication number Publication date
AU2003274003A1 (en) 2004-05-04
DE10247807A1 (en) 2004-04-22
AU2003274003A8 (en) 2004-05-04

Similar Documents

Publication Publication Date Title
EP0800495B1 (en) Production of an aluminide-containing ceramic moulding
EP0984839B1 (en) Metal-ceramic graded-index material, product produced from said material, and method for producing the material
EP1364732B1 (en) Hard metal part with graded structure
EP1718777B1 (en) Method for the production of a molybdenum alloy
DE112007000923B4 (en) Composite material of metal and ceramic, process for its production, its use and energy absorption component
DE112009000280B4 (en) Polycrystalline MgO sintered body and MgO sputtering target
EP0902771B1 (en) Metal-ceramic shaped body and process for manufacturing the same
WO1996020902A9 (en) Production of an aluminide-containing ceramic moulding
DE3010545C2 (en) Sintered ceramics, in particular for cutting tools, and processes for producing the same
EP1685081B1 (en) Method for producing a composite part and metal/ceramic part
EP0433856A1 (en) Mixed hard metal materials based on borides, nitrides and iron group matrix metals
DE102012021906A1 (en) Ceramic composite material for metallurgy-material-affecting conservation, comprises composite obtained by mixing substance portions of silicon nitride and zirconium oxide, and surface layer obtained by heat-treating composite
EP2730551B1 (en) Method for the production of a refractory material based of magnesia or magnesia spinel and a refractory material based of magnesia or magnesia spinel
EP1412113A2 (en) Sinter metal parts with homogeneous distribution of non-homogeneously melting components and method for the production thereof
EP1560799A2 (en) Ceramic-metal or metal-ceramic composite
DE3924267C1 (en) Arrangement for use as protection against projectiles
WO2004035309A1 (en) Composite metal/ceramic product having surface compressive stresses
AT10479U1 (en) FLUID-DENSITY SINTERED METAL PARTS AND METHOD FOR THE PRODUCTION THEREOF
DE202012010696U1 (en) Ceramic composite material and formed by this component
DE10354655A1 (en) Composite component is formed by placing a reactive material powder in a mould, pressing, sintering, and infiltration with a metal melt
EP1548137B1 (en) Use of a hard metal for tools
WO2008086930A1 (en) Ceramic preform for the production of metal-ceramic composite materials
DE4440544C2 (en) Sintered hard material molded body and process for its production
DE4437463A1 (en) Creep resistant high temp. nickel@-aluminium@ material
EP0776872A1 (en) Metal-ceramic composite material and process for its preparation

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP