Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/008—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 characterised by the composition
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C47/00—Making alloys containing metallic or non-metallic fibres or filaments
  • C22C47/14—Making alloys containing metallic or non-metallic fibres or filaments by powder metallurgy, i.e. by processing mixtures of metal powder and fibres or filaments
• • 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
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/043—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of metal
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C26/00—Alloys containing diamond or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C49/00—Alloys containing metallic or non-metallic fibres or filaments
  • C22C49/02—Alloys containing metallic or non-metallic fibres or filaments characterised by the matrix material
  • C22C49/04—Light metals
  • C22C49/06—Aluminium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C49/00—Alloys containing metallic or non-metallic fibres or filaments
  • C22C49/14—Alloys containing metallic or non-metallic fibres or filaments characterised by the fibres or filaments
• • 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
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/0408—Light metal alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/0408—Light metal alloys
  • C22C1/0416—Aluminium-based alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C26/00—Alloys containing diamond or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes
  • C22C2026/002—Carbon nanotubes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12639—Adjacent, identical composition, components
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12986—Adjacent functionally defined components
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/19—Gearing

Definitions

• a compound material comprising a metal and nanoparticles and a method for producing the same
• the present invention relates to compound materials comprising a metal and nanoparticles, in particular carbon nano tubes (CNT) as well as to methods for producing the same.
• CNT carbon nano tubes
• Carbon nano tubes sometimes also referred to as “carbon fibrils” or “hollow carbon fibrils”, are typically cylindrical carbon tubes having a diameter of 3 to 100 ran and a length which is a multiple of their diameter.
• CNTs may consist of one or more layers of carbon atoms and are characterized by cores having different morphologies.
• CNTs have been known from the literature for a long time. While Iijima (s. Iijima, Nature 354, 56 - 58, 1991) is generally regarded as the first to discover CNTs, in fact fibre shaped graphite materials having several graphite layers have been known since the 1970s and 1980s. For example, in GB 14 699 30 Al and EP 56 004 A2, Tates and Baker described for the first time the deposition of very fine fibrous carbon from a catalytic decomposition of hydrocarbons. However, in these publications the carbon filaments which are produced based on short- chained carbohydrates are not further characterized with respect to their diameter.
• the most common structure of carbon nano tubes is cylindrical, wherein the CNT may be either comprised of a single graphene layer (single- wall carbon nano tubes) or of a plurality of concentric graphene layers (multi-wall carbon nano tubes).
• Standard ways to produce such cylindrical CNTs are based on arch discharge, laser ablation, CVD and catalytic CVD proc- esses.
• Iijima Nature 354, 56 - 58, 1991
• the formation of CNTs having two or more graphene layers in the form of concentric seamless cylinders using the arch discharge method is described.
• chiral and antichiral arrangements of the carbon atoms with respect to the CNT longitudinal axis are possible.
• CNTs have truly remarkable characteristics with regard to electric conductivity, heat conductivity and strength.
• CNTs have a hardness exceeding that of diamond and a tensile strength ten times higher than steel. Consequently, there has been a continuous effort to use CNTs as constituent in compound or composite materials such as ceramics, polymer materials or metals trying to transfer some of these advantageous characteristics to the compound material.
• a method of producing a CNT dispersed composite material in which a mixed powder of ceramics and metal and long-chain carbon nano tubes are kneaded and dispersed by a ball mill, and the dispersed material is sintered using discharge plasma. If aluminum is used for the metal, the preferred particle size is 50 to 150 ⁇ m.
• WO 2006/123 859 Al Another related method of obtaining a metal-CNT-composite material is described in WO 2006/123 859 Al.
• metal powder and CNTs are mixed in a ball mill at a milling speed of 300 rpm or more.
• One of the main objects of this prior art is to ensure a directionality of the CNTs in order to enhance the mechanical and electrical properties.
• the directionality is imparted to the nano fibrils by application of a mechanical mass flowing process to the composite material with the nano fibrils uniformly dispersed in the metal, where the mass flowing process could for example be extrusion, rolling or injection of the composite material.
• WO 2008/052 642 and WO 2009/010 297 of the present inventors disclose a further method of producing a composite material containing CNTs and a metal.
• the composite material is produced by mechanical alloying using a ball mill, where the balls are accelerated to very high velocities up to 11 m/s or even 14 m/s.
• the resulting composite material is characterized by a layered structure of alternating metal and CNT layers, where the individual layers of the metal material may be between 20 and 200,000 nm thick and the individual layers of the CNT may be between 20 and 50,000 nm thickness.
• the layer structure of this prior art is shown in Fig. 11a.
• JP 2009 03 00 90 yet an alternative way of forming the CNT metal compound material is proposed.
• a metallic powder having an average primary particle size of 0.1 ⁇ m to 100 ⁇ m is immersed in a solution containing CNTs, and the CNTs are attached to the metal parti- cles by hydrophilization, thereby forming a mesh-shaped coating film on top of the metal powder particles.
• the CNT coated metallic powder can then be further processed in a sintering process.
• a stacked metal composite may be formed by stacking the coated metal composite on a substrate surface. The resultant composite is reported to have superior mechanical strength, electric conductivity and thermal conductivity.
• Fig. 5 is a graph showing the size distribution of CNT-agglomerates obtained with a production setup shown in Fig. 1
• the inventors have analyzed the kinetics of the balls using high speed stroboscopic cinematopography and could confirm that the maximum relative velocity of the balls corresponds approximately to the maximum velocity of the tips of the rotating arms 48. While in all types of ball mills the processed media are subjected to collision forces, shear forces and frictional forces, at higher kinetic energies the relative amount of energy transferred by collision increases. In the framework of the present invention, it is preferred that from the total mechanical work applied to the processed media, the relative contribution of collisions is as high as possible. For this reason, the high energy ball mill 42 shown in Fig. 8 is advantageous over ordinary drum-ball mills, planetary ball mills or attritors since the kinetic energy of the balls that can be reached is higher.
• the CNT will tend to be damaged to a degree that the envisaged nano- stabilization is greatly compromised.
• a powder composite material can be obtained in which metal crystallites having a high dislocation density and a mean size below 200 run, preferably below 100 nm are at least partially separated and micro-stabilized by homogeneously distributed CNTs.
• Fig. 11a shows a cut through a composite material particle according to an embodiment of the invention.
• the metal constituent is aluminum and the CNTs are of the multi-scroll type obtained in a process as described in section 1 above.
• the composite material is characterized by an isotropic distribution of nanoscopic metal crystallites located in a CNT mesh structure.
• the composite material of WO 2008/052642 shown in Fig. l ib has a non-isotropic layer structure, leading to non- isotropic mechanical properties.
• Passivation of the powder again facilitates the handling of the powder as a source material for fabrication of manufactured or semi-finished articles on an industrial scale.

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

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• 2010
  • 2010-01-28 EP EP10702606A patent/EP2396443A1/de not_active Withdrawn

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