WO2019120388A1 - Method for producing a sintered gradient material, sintered gradient material and use thereof - Google Patents

Method for producing a sintered gradient material, sintered gradient material and use thereof Download PDF

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Publication number
WO2019120388A1
WO2019120388A1 PCT/DE2018/101039 DE2018101039W WO2019120388A1 WO 2019120388 A1 WO2019120388 A1 WO 2019120388A1 DE 2018101039 W DE2018101039 W DE 2018101039W WO 2019120388 A1 WO2019120388 A1 WO 2019120388A1
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Prior art keywords
component
permanent
layer
carrier
permanent magnetic
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PCT/DE2018/101039
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German (de)
French (fr)
Inventor
Eberhard Burkel
Wiktor BODNAR
Kerstin Witte
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Universität Rostock
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Priority to DE112018006507.3T priority Critical patent/DE112018006507A5/en
Publication of WO2019120388A1 publication Critical patent/WO2019120388A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • 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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
    • B22F2003/1051—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding by electric discharge
    • 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
    • B22F2207/00—Aspects of the compositions, gradients
    • B22F2207/01—Composition gradients
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C2202/00—Physical properties
    • C22C2202/02—Magnetic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0273—Imparting anisotropy
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the invention relates to a method for producing a sintered gradient material comprising at least one permanent-magnetic component and at least one carrier component and a mechanically stable gradient material itself produced therefrom. According to the method, permanent-magnetic gradient materials can be produced for industrial applications.
  • Permanent magnets also referred to as permanent magnets
  • permanent magnets have long been used in industry for various applications u.a. used in electronics, mechanics and electromechanics.
  • permanent magnets e.g. in permanent magnet motors and the generators of wind turbines.
  • the permanent magnet is mechanically connected as a component on or with another component me.
  • bodies of permanent magnet material such as Nd 2 Fe 4 B
  • bodies made of steel or other materials because the bodies have different thermal expansion coefficients and also different magnetostriction coefficients, which makes it possible to contact the bodies of the body Stress formation comes, which leads to the formation of cracks in the sequence and thus reduces the life of the components and increases the risk of failure.
  • Gradient materials differ from conventional materials of a uniform nature, which change abruptly from one material to another at their abutting surfaces, in that at least one property changes continuously or stepwise with respect to a spatial direction of the gradient material.
  • Gradient materials are monolithic materials with altered properties in one or more directions.
  • the gradient material consists of pure components lying on opposite sides between which the structure, the composition and / or the morphology changes stepwise or continuously from one component to the other component.
  • the simplest structure of such a gradient material consists of two or more components, each representing different materials or mixtures of materials, wherein the concentration of the components changes in at least one direction.
  • Gradient materials are described, for example, in EP 1712657 B1, in which a method for the production of gradient materials from different metallic starting materials, such as e.g. Titanium, nickel, aluminum, magnesium or metal alloys by means of cold spraying is described.
  • the object of the present invention is to provide permanent magnets made of new materials with improved or at least new properties, in particular the problems known from the prior art, which are associated with the above-described stress and cracking, e.g. when mounting the permanent magnets in machines, to avoid.
  • sintered gradient materials comprising at least one permanent-magnetic component and at least one carrier component can be produced, with the sintered gradient material according to the invention compared to conventional components in which magnetic and non-magnetic bodies are connected to contact surfaces, show improved properties, in particular with regard to stress and crack formation.
  • the gradient material according to the invention is produced from two or more components which each represent different materials, wherein the concentration of the components in the gradient material changes in at least one direction and at least one component comprises a permanent magnetic material.
  • the gradient material is produced by building up a body or a layer to be consolidated with a layer-by-layer changing concentration of the components used, so that in at least one spatial direction an ascending and preferably for at least one other component in a different spatial direction, especially in the opposite direction, gives a decreasing concentration profile. It follows that there is a change in the properties with the concentration profile of the respective material.
  • the first component in this case comprises a material or a material mixture and the second component comprises a material or a material mixture, wherein at least one material in the first component is permanently magnetic and in particular at least one material in the first component is different from each material in the second component is.
  • the gradient material thus comprises at least two components, each of which may be made of one or more materials. At least one of the components is a permanent magnetic component.
  • the permanent-magnetic component comprises, for example, in powder form in each case:
  • Bismuth, manganese and iron alloys e.g. Bismanol
  • Yttrium can also play the role of a rare earth metal;
  • the most important representatives are neodymium-iron-boron (particularly Nd2Fei 4 B), samarium cobalt (especially SmCos and Srri2Coi7) and samarium-iron-nitrogen (Srri2Fei8N3).
  • the other component is the carrier component, which is chosen, for example, such that it corresponds to or at least resembles the material of the application construction on which the permanent magnet is to be fastened.
  • the carrier component is different from the permanent magnetic component used, in particular the carrier material is non-permanent magnetic and / or paramagnetic. According to one embodiment, the carrier component consists exclusively of the non-permanent magnetic and / or paramagnetic carrier material.
  • a suitable carrier component or excipient which may be used in the gradient are powders, e.g. various steels, titanium or aluminum alloys, metallic glasses or ceramics such as WC, AI2O3 or Zr02.
  • Powder or powder form means in the present case that it is one or more particulate, free-flowing components, in particular having particle sizes of less than 1000 ⁇ m, in particular of e.g. 10 nanometers to 500 microns, as can be determined by sieve analysis, static or dynamic light scattering, transmission electron microscopy and physisorption.
  • the method according to the invention comprises the step of sintering, in particular the so-called field-supported sintering or additive methods such as laser or electron beam melting.
  • sintering in particular the so-called field-supported sintering or additive methods such as laser or electron beam melting.
  • the process which is also referred to as (FAST)
  • at least one permanent-magnetic component having at least one carrier component is compacted to form a mechanically stable gradient material.
  • This is a pressure-assisted sintering process with pulsed direct current in a press tool.
  • the material to be processed is introduced into a sintering chamber and pressed.
  • a pulsed current flows directly through the introduced components / materials, which have the concentration profile described above.
  • electrically conductive materials a significant increase in the compression rate is achieved by the influence of the electric field and the current flow.
  • the pressing tool makes it possible according to one embodiment, to achieve heating rates up to 1000 K / min.
  • the advantages of the FAST method compared to other methods is the possibility to connect different materials with each other through the pulsed direct current as well as the induced electric and magnetic fields.
  • the pulsed direct current also means that, for example, by a suitable choice of the sintering chamber, additional temperature gradients can be caused, which also make it easier to connect different materials together.
  • At least the permanent-magnetic component and the carrier material component are introduced in layers in the form of mixtures of different concentrations in powder form into the chamber of the pressing tool and there precompressed in layers, so that the desired concentration profile is established. Thereafter, under a uniaxial pressure of e.g. 10 to 300 MPa and in particular 50 MPa to 80 MPa in a vacuum or a protective gas atmosphere at 600 to 1900 ° C, in particular 800 ° C to 1200 ° C heated by the flow of current.
  • a voltage of below 8 V, in particular below 5 V, and a current of 1 kA to 10 kA are typically selected.
  • Another big advantage of the FAST process for gradient material production is the short process time. This leads to a reduction of the grain growth in the sintering process, whereby a nano- and microstructure in the grain of the material is maintained. This has positive effects on the mechanical properties of the material.
  • gradient materials having a weight fraction of from 10% by weight to 90% by weight, preferably from 50% by weight to 90% by weight, of the permanent-magnetic component are formed relative to the total weight of the gradient material.
  • the starting components for the synthesis in the FAST process can be prepared in a ball mill to give powder mixtures of suitable concentration.
  • powder mixtures with a graduated concentration can be realized, for example from 100% by weight of the permanent-magnetic component, decreasing in steps (each forming one layer) of in each case 10% by weight (concentration gradient) up to 0% by weight of the permanent-magnetic component and correspondingly opposite increasing concentration of the carrier component.
  • the layers are each provided in the form of several layers of a powder mixture of respective powders containing on the one hand the carrier component and on the other hand the permanent-magnetic component.
  • the concentration of the carrier component and the permanent magnetic component changes from layer to layer along the spatial direction.
  • the layers in the spatial direction opposite to the layer-to-layer concentration of the permanent magnetic material from layer to layer, have a decreasing concentration of the carrier component, sloping from a first layer containing 100% of the carrier component. component.
  • the first layer consists exclusively of the carrier component or consists exclusively of the carrier material if the carrier component consists exclusively of the carrier material.
  • the concentration of the carrier material decreases in the spatial direction.
  • the concentration of the permanent magnetic material increases along the spatial direction.
  • the proportion of permanent magnetic material at the end of the gradient material is preferably 100%.
  • the gradient material according to the invention comprises at least four layers each of at least one permanent-magnetic component and at least one carrier component for obtaining a lamination, wherein the permanent-magnetic component comprises at least one permanent-magnetic material and the carrier component comprises at least one carrier material which differs from the permanent-magnetic component ,
  • the components are comminuted and mixed into particle sizes ranging from nanometers to micrometers.
  • this process can also be used to achieve ideal homogenization of the component mixtures of the intermediate layers.
  • the individual powder mixtures are then stacked in the FAST chamber.
  • the at least four layers are precompressed in the FAST chamber and then heated to 600 ° C - 1900 ° C under a uniaxial pressure of 10 MPa to 300 MPa in a vacuum or inert gas atmosphere.
  • a voltage of less than 8 V and a current of 1 kA - 10 kA are chosen.
  • the sintering can be done in an external magnetic field
  • the powders used are aligned during the application of the FAST method for obtaining a solid body in an electric or magnetic field.
  • an electromagnet in the wall surrounding the FAST chamber, or a coil around the graphite mold, which in operation causes a homogeneous magnetic field in the chamber and thus additionally by aligning during sintering the energy product of the Permanent magnets can maximize.
  • This may be particularly advantageous for aligning the permanent-magnetic gradient material in a single step after the sintering process, since the permanent-magnetic component of the gradient material loses its ferromagnetic or ferrimagnetic properties above the material-specific Curie temperature, so that they are only paramagnetic above.
  • additional temperature gradients can be obtained. This can be used, for example, if the ferromagnetic material and the carrier material have different sintering temperatures.
  • a graphite container in the shape of a truncated cone an additional temperature gradient can be produced. Due to the cone shape, the current density changes depending on the position of the cone and thus the resulting temperature in the mold. The narrower part of the truncated cone will have a lower temperature compared to the larger diameter section.
  • step by step powder layer for powder layer is compressed and FAST-sintered.
  • the sintered gradient material can be used as a permanent magnet.
  • a permanent magnet is a magnet made of one piece of ferromagnetic or ferrimagnetic material, for example alloys of iron, cobalt, nickel or certain ferrites. He has and retains a static magnetic field, without the need for an electric current flow as with electromagnets. Permanent magnets each have one or more north and south poles (e) on their surface.
  • Permanent magnets can be generated by the action of a magnetic field on a ferrimagic or ferromagnetic material.
  • a decaying alternating magnetic field, heating or impact can demagnetize permanent magnets.
  • Typical applications of the magnets according to the invention are holding magnets and field magnets of direct current motors, generators, wind power generators, magnetrons and electrodynamic loudspeakers, microphones or in particle accelerators as deflection or focusing magnets in wigglers and undulators or holders for such devices.
  • the required powder mixtures or the pure powders (in the end positions) were previously ground in a ball mill in hexane for 2 h at 200 rpm with a ball to powder weight ratio of 10: 1 and mixed together ,
  • the powder blends were then layered together in a graphite container (chamber of the press tool) with an inside diameter of 20 mm and the container with the graphite punches placed at both ends in the FAST chamber.
  • the powder was then subjected to an initial pressure of 10 MPa in the graphite container in the FAST chamber under vacuum (phase 1). In the following 6 min, a pressure of 80 MPa was steadily built up (phase 2).
  • the pulsed direct current used for the FAST process was up to 1.6 kA and the voltage up to 5 V and varied depending on the temperature during the sintering process.
  • the sample was brought to 420 ° C (phase 3) in a first heating process. This step is necessary for technical reasons, since the pyrometer used starts working at 400 ° C.
  • the body was heated at a heating rate of 100 K / min to a temperature of 800 ° C (Phase 4).
  • the holding time of the sintering process at 800 ° C was 5 min (phase 5).
  • the heating process including field-supported sintering, lasted for a total of 10 minutes. Thereafter, the power was turned off but the pressure on the body was maintained (phase 6). The layering of powders produced a body. After the sintering process was completed, sandblasting was used to free the body of any graphite residue and to obtain the gradient material.
  • the invention or the materials obtained according to the examples are further explained with reference to the following figures. Show it:
  • Fig. 1 Time course of the sintering process
  • FIG. 2 optical micrograph of a neodymium-iron-boron / steel gradient material
  • Fig. 3 XRD diffractograms of 7 exemplary layers of the gradient
  • FIG. 4 Phase components of the contributing main phases in the 1 1 layers of the gradient material
  • FIG. 5 lattice parameters of the contributing main phases in the 1 1 layers of the gradient material
  • FIG. 6 Thermal expansion of exemplary compositions as a function of the temperature.
  • the sintering process is essentially described by the 6 phases mentioned above in the text.
  • the obtained neodymium-iron-boron / steel sintered gradient material is shown in FIG.
  • the relative densities of the neodymium iron, stainless steel and each of the 9 interlayers are above 98% of theoretical.
  • the densities of the individual layers were determined on separately sintered specimens using the Archimedian principle. The gradual transition from Neodymeisenbor (left) to steel (right) can be seen in a total of 9 intermediate steps.
  • the structure along the gradient is shown by way of example on 7 layers in FIG. 3 on the basis of the X-ray diffractograms.
  • the phase composition can be obtained, for example, using the XRD data from the Rietveld analysis.
  • the scattering intensities of the individual phases as well as the total intensity of the individual phases in the diffractograms must be taken into account.
  • the phase composition of the gradient material is shown in FIG.
  • the main contributing phases were neodymium iron, austenitic steel and iron in the alpha phase (ferrite).
  • the ferrite phase occurred due to partial decomposition of the neodymium iron.
  • a neodymium-rich as well as a boron-rich phase is formed during the decomposition, but these have only a small phase fraction of less than 5% by volume at maximum, so that they were not taken into account in FIG. 4. It should be noted that the appearance of the ferrite does not adversely affect the magnetic properties of the neodymium iron.
  • the lattice parameters for the main phases, Figure 5 show slight changes along the 1 l layers, with the largest changes occurring at the transition from the initial pure neodymium iron borate phase to the next layer. These differences in the lattice parameters indicate internal stress in the material, which can reduce the stability of the gradient and also lead to cracks at these edges. Based on Flook's law, the changes in the lattice constants along the position of the gradient can be converted into an internal stress and thus show that for the described gradient the maximum stress occurring lies below the tensile strength of the contributing phases, so that the Gradient is mechanically stable.
  • the thermal expansion of individual gradient layers is shown graphically in FIG. 6. These were examined by dilatometry. The thermal expansion of samples from 7 layers of the produced neodymium-iron-boron / steel gradient material was determined with increasing temperature. The result clarifies that the layers with only neodymium-iron-boron compare with the layer of steel only have a very different coefficient of thermal expansion. By introducing intermediate layers, the large difference in the transition from one layer to the next can be minimized, which also has a positive influence on the sintering process and the overall stability of the gradient material.

Abstract

The present invention relates to a method for producing a sintered gradient material from at least one permanently magnetic component and at least one carrier component and to a mechanically stable gradient material produced therefrom. According to this method, permanently magnetic gradient materials for industrial applications can be produced.

Description

Verfahren zur Herstellung eines gesinterten Gradientenmaterials, gesintertes Gradientenmaterial und dessen Verwendung  Method for producing a sintered gradient material, sintered gradient material and its use
Die Erfindung betrifft ein Verfahren zur Herstellung eines gesinterten Gradientenma- terials aus mindestens einer permanentmagnetischen Komponente und mindestens einer Trägerkomponente sowie ein daraus hergestelltes mechanisch stabiles Gradien- tenmaterial selbst. Nach dem Verfahren können permanentmagnetische Gradienten- materialien für industrielle Anwendungen hergestellt werden. The invention relates to a method for producing a sintered gradient material comprising at least one permanent-magnetic component and at least one carrier component and a mechanically stable gradient material itself produced therefrom. According to the method, permanent-magnetic gradient materials can be produced for industrial applications.
Stand der Technik State of the art
Permanentmagnete, auch als Dauermagnete bezeichnet, werden seit langem in der Industrie für unterschiedliche Einsatzbereiche u.a. in der Elektronik, Mechanik und Elektromechanik verwendet. Ebenfalls werden Permanentmagnete z.B. in Permanent- magnetmotoren und den Generatoren von Windkraftanlagen, eingesetzt. Die meisten Permanentmagnete, die heutzutage in der Industrie bspw. in Elektromotoren, Laut- sprechern, Bildröhren oder Mikrowellen eingesetzt werden, sind Seltenerdmagneten. Mit Seltenerdmagneten kann ein hohes Energieprodukt erhalten werden. Permanent magnets, also referred to as permanent magnets, have long been used in industry for various applications u.a. used in electronics, mechanics and electromechanics. Also, permanent magnets, e.g. in permanent magnet motors and the generators of wind turbines. Most permanent magnets used in industry today, for example in electric motors, loudspeakers, picture tubes or microwaves, are rare earth magnets. With rare earth magnets, a high energy product can be obtained.
Oft ist der Permanentmagnet als ein Bauteil auf oder mit einem anderen Bauteil me chanisch verbunden. Es ist aber oft problematisch Körper aus Permanentmagnetma- terial wie Nd2Fei4B mit Körpern aus Stahl oder anderen Materialien in Kontakt zu brin- gen, weil die Körper unterschiedliche thermische Ausdehnungskoeffizienten und auch unterschiedlichen Magnetostriktionskoeffizienten aufweisen, womit es an den Kontakt- flächen der Körper zur Stressbildung kommt, welche in der Folge zur Rissbildung führt und damit die Lebensdauer der Bauteile reduziert und das Ausfallrisiko erhöht. Often, the permanent magnet is mechanically connected as a component on or with another component me. However, it is often problematic to bring bodies of permanent magnet material such as Nd 2 Fe 4 B into contact with bodies made of steel or other materials, because the bodies have different thermal expansion coefficients and also different magnetostriction coefficients, which makes it possible to contact the bodies of the body Stress formation comes, which leads to the formation of cracks in the sequence and thus reduces the life of the components and increases the risk of failure.
Gradientenmaterialien unterscheiden sich von herkömmlichen Materialen einheitlicher Natur, die an ihren Stoßflächen sprunghaft von einem Material in ein anders überge- hen, dadurch, dass sich zumindest eine Eigenschaft in Bezug auf eine Raumrichtung des Gradientenmaterial kontinuierlich oder schrittweise ändert. Bei Gradientenmateri- alien handelt es sich um monolithische Werkstoffe mit in einer oder mehreren Richtun- gen veränderten Eigenschaften. Nach einer Ausgestaltung besteht das Gradienten- material aus an gegenüberliegenden Seiten liegenden reinen Komponenten zwischen denen sich die Struktur, die Zusammensetzung und/oder die Morphologie schrittweise oder kontinuierlich von der einen Komponente in die andere Komponente ändert. Die einfachste Struktur eines solchen Gradientenmaterials besteht aus zwei oder mehr Komponenten, die jeweils unterschiedliche Materialien oder Mischungen von Materia- lien darstellen, wobei sich die Konzentration der Komponenten in zumindest einer Richtung ändert. Gradient materials differ from conventional materials of a uniform nature, which change abruptly from one material to another at their abutting surfaces, in that at least one property changes continuously or stepwise with respect to a spatial direction of the gradient material. Gradient materials are monolithic materials with altered properties in one or more directions. According to one embodiment, the gradient material consists of pure components lying on opposite sides between which the structure, the composition and / or the morphology changes stepwise or continuously from one component to the other component. The simplest structure of such a gradient material consists of two or more components, each representing different materials or mixtures of materials, wherein the concentration of the components changes in at least one direction.
Gradientenmaterialien sind bspw. in der EP 1712657 B1 beschrieben, in der ein Ver- fahren zur Herstellung von Gradientenmaterialien aus unterschiedlichen metallischen Ausgangsmaterialien, wie z.B. Titan, Nickel, Aluminium, Magnesium oder auch von Metalllegierungen mittels Kaltspritzen beschrieben ist. Gradient materials are described, for example, in EP 1712657 B1, in which a method for the production of gradient materials from different metallic starting materials, such as e.g. Titanium, nickel, aluminum, magnesium or metal alloys by means of cold spraying is described.
Aufgabe der Erfindung Object of the invention
Aufgabe der vorliegenden Erfindung ist es, Permanentmagneten aus neuen Materia- len mit verbesserten oder zumindest neuen Eigenschaften zur Verfügung zu stellen, insbesondere um die aus dem Stand der Technik bekannten Probleme, die mit oben beschriebener Stress- und Rissbildung verbunden sind, z.B. bei der Befestigung der Permanentmagnete in Maschinen, zu vermeiden. The object of the present invention is to provide permanent magnets made of new materials with improved or at least new properties, in particular the problems known from the prior art, which are associated with the above-described stress and cracking, e.g. when mounting the permanent magnets in machines, to avoid.
Zusammenfassung der Erfindung Summary of the invention
Erfindungsgemäß wird die Aufgabe entsprechend den Merkmalen der unabhängigen Patentansprüche gelöst. Bevorzugte Ausführungsformen sind Gegenstand der Unter- ansprüche oder sind nachfolgend beschrieben. According to the invention the object is achieved according to the features of the independent claims. Preferred embodiments are the subject of the subclaims or are described below.
Überraschend wurde gefunden, dass sich durch Sintern, insbesondere durch feldge- stütztes Sintern, sogenanntes FAST-Sintern, gesinterte Gradientenmaterialien, umfas- send zumindest eine permanentmagnetische Komponente und zumindest einem Trä- gerkomponente hersteilen lassen, wobei das erfindungsgemäße gesinterte Gradien- tenmaterial gegenüber herkömmlichen Bauteilen in denen magnetische und nicht magnetische Köper an Kontaktflächen in Verbindung stehen, verbesserte Eigenschaf- ten, insbesondere in Bezug auf Stress- und Rissbildung zeigen. Surprisingly, it has been found that by sintering, in particular by field-supported sintering, so-called FAST sintering, sintered gradient materials comprising at least one permanent-magnetic component and at least one carrier component can be produced, with the sintered gradient material according to the invention compared to conventional components in which magnetic and non-magnetic bodies are connected to contact surfaces, show improved properties, in particular with regard to stress and crack formation.
Das erfindungsgemäße Gradientenmaterial ist hergestellt aus zwei oder mehr Kompo- nenten, die jeweils unterschiedliche Materialien darstellen, wobei sich die Konzentra- tion der Komponenten in dem Gradientenmaterial in zumindest einer Richtung ändert und zumindest eine Komponente ein permanentmagnetisches Material umfasst. Das Gradientenmaterial wird hergestellt, indem ein Körper bzw. eine zu verfestigende Schichtung mit sich schichtweise ändernder Konzentration der eingesetzten Kompo- nenten aufgebaut wird, so dass sich in zumindest eine Raumrichtung ein ansteigendes und vorzugsweise für zumindest eine andere Komponente in einer anderen Raumrich- tung, insbesondere der entgegengesetzten Raumrichtung, ein abfallendes Konzentra- tionsprofil ergibt. Hieraus folgt, dass sich eine Änderung der Eigenschaften mit dem Konzentrationsprofil des jeweiligen Materials ergibt. Die erste Komponente umfasst dabei ein Material bzw. eine Materialmischung und die zweite Komponente ein Mate- rial bzw. eine Materialmischung, wobei zumindest ein Material in der ersten Kompo- nente permanentmagnetisch ist und insbesondere zumindest ein Material in der ersten Komponente unterschiedlich von jedem Material in der zweiten Komponente ist. The gradient material according to the invention is produced from two or more components which each represent different materials, wherein the concentration of the components in the gradient material changes in at least one direction and at least one component comprises a permanent magnetic material. The gradient material is produced by building up a body or a layer to be consolidated with a layer-by-layer changing concentration of the components used, so that in at least one spatial direction an ascending and preferably for at least one other component in a different spatial direction, especially in the opposite direction, gives a decreasing concentration profile. It follows that there is a change in the properties with the concentration profile of the respective material. The first component in this case comprises a material or a material mixture and the second component comprises a material or a material mixture, wherein at least one material in the first component is permanently magnetic and in particular at least one material in the first component is different from each material in the second component is.
Überraschend kommt es hierbei für benachbarte Zonen senkrecht zu Raumrichtung des Konzentrationsprofils zu einer verminderten Änderung der physikalischen Eigen- schaften wie des thermischen Ausdehnungskoeffizienten und des Magnetostriktions- koeffizienten, wodurch eine Minimierung des Stresses innerhalb des gesinterten Gra- dientenmaterials erreicht wird. Surprisingly, for adjacent zones perpendicular to the spatial direction of the concentration profile, there is a reduced change in the physical properties, such as the coefficient of thermal expansion and the magnetostriction coefficient, whereby minimization of the stress within the sintered gradient material is achieved.
Detaillierte Beschreibung der Erfindung Detailed description of the invention
Das Gradientenmaterial umfasst somit zumindest zwei Komponenten, welche jeweils aus einem oder mehreren Materialien hergestellt sein können. Zumindest eine von den Komponenten ist eine permanentmagnetische Komponente. The gradient material thus comprises at least two components, each of which may be made of one or more materials. At least one of the components is a permanent magnetic component.
Die permanentmagnetische Komponente umfasst nach einer Ausgestaltung beispiel- haft jeweils in Pulverform: According to one embodiment, the permanent-magnetic component comprises, for example, in powder form in each case:
- Eisenlegierungen umfassend neben Eisen, Aluminium, Nickel und Cobalt als Hauptlegierungselemente;  - Iron alloys comprising, in addition to iron, aluminum, nickel and cobalt as main alloying elements;
- Legierungen aus Bismut, Mangan und Eisen, wie z.B. Bismanol;  Bismuth, manganese and iron alloys, e.g. Bismanol;
- Legierungen enthaltend Eisen, Cobalt Nickel und/oder Seltenerdmetalle (insbe- sondere Neodym, Samarium, Praseodym, Dysprosium, Terbium, Gadolinium). Auch Yttrium kann die Rolle eines Seltenerdmetalls einnehmen; Die wichtigsten Vertreter sind Neodym-Eisen-Bor (insbesondere Nd2Fei4B), Samarium-Cobalt (insbesondere SmCos und Srri2Coi7) und Samarium-Eisen-Stickstoff (Srri2Fei8N3). Diese könne auch modifiziert werden etwa, indem in Nd2Fei4B Neodym teilweise durch Praseodym, Dysprosium, Terbium und Eisen teilweise durch Cobalt substituiert wird - oder indem das Gefüge durch fremde Atome wie Aluminium, Titan, Zirconium, Kupfer oder Mangan gestört wird. Die andere Komponente ist die Trägerkomponente, die z.B. so gewählt ist, dass diese dem Material der Anwendungskonstruktion auf der der Permanentmagnet befestigt werden soll entspricht oder zumindest ähnelt. Die Trägerkomponente ist von der ein- gesetzten permanentmagnetischen Komponente unterschiedlich, insbesondere ist das Trägermaterial nicht-permanentmagnetisch und/oder paramagnetisch. Nach einer Ausführungsform besteht die Trägerkomponente ausschließlich aus dem nicht-perma- nentmagnetischen und/oder paramagnetischen Trägermaterial. - Alloys containing iron, cobalt nickel and / or rare earth metals (in particular neodymium, samarium, praseodymium, dysprosium, terbium, gadolinium). Yttrium can also play the role of a rare earth metal; The most important representatives are neodymium-iron-boron (particularly Nd2Fei 4 B), samarium cobalt (especially SmCos and Srri2Coi7) and samarium-iron-nitrogen (Srri2Fei8N3). This can also be modified, for example, by partially substituting praseodymium, dysprosium, terbium and iron with cobalt in Nd2Fei 4 B neodymium - or by disrupting the microstructure by foreign atoms such as aluminum, titanium, zirconium, copper or manganese. The other component is the carrier component, which is chosen, for example, such that it corresponds to or at least resembles the material of the application construction on which the permanent magnet is to be fastened. The carrier component is different from the permanent magnetic component used, in particular the carrier material is non-permanent magnetic and / or paramagnetic. According to one embodiment, the carrier component consists exclusively of the non-permanent magnetic and / or paramagnetic carrier material.
Eine geeignete Trägerkomponente oder ein geeignetes Trägermaterial, die in dem Gradienten verwendet werden können, sind Pulver wie z.B. verschiedene Stähle, Ti tan- oder Aluminiumlegierungen, metallische Gläser oder Keramiken wie WC, AI2O3 oder Zr02. A suitable carrier component or excipient which may be used in the gradient are powders, e.g. various steels, titanium or aluminum alloys, metallic glasses or ceramics such as WC, AI2O3 or Zr02.
Pulver oder Pulverform meint vorliegend, dass es sich um eine oder mehrere partiku- läre, schüttfähige Komponenten handelt, insbesondere mit Partikelgrößen von kleiner 1000 pm, insbesondere von z.B. 10 Nanometern bis 500 Mikrometer, wie diese durch Siebanalyse, statische oder dynamische Lichtstreuung, Transmissionselektronenmik- roskopie als auch Physisorption bestimmt werden kann. Powder or powder form means in the present case that it is one or more particulate, free-flowing components, in particular having particle sizes of less than 1000 μm, in particular of e.g. 10 nanometers to 500 microns, as can be determined by sieve analysis, static or dynamic light scattering, transmission electron microscopy and physisorption.
Das erfindungsgemäße Verfahren umfasst den Schritt des Sinterns, insbesondere das sogenannte feldgestützte Sintern oder additive Verfahren wie Laser- oder Electron beam melting. Mit dem auch als (FAST) bezeichneten Verfahren wird zumindest eine permanentmagnetische Komponente mit zumindest einer Trägerkomponente zu ei- nem mechanisch stabilen Gradientenmaterial verdichtet. Dies ist ein druckunterstütz- tes Sinterverfahren mit gepulstem Gleichstrom in einem Presswerkzeug. Hierzu wird das zu verarbeitende Material in eine Sinterkammer eingebracht und gepresst. Zur Wärmeeinbringung fließt ein gepulster Strom direkt durch die eingebrachten Kompo- nenten / Materialen, welche das weiter oben beschriebene Konzentrationsprofil auf- weisen. Für elektrisch leitende Materialien wird eine signifikante Steigerung der Ver- dichtungsrate durch den Einfluss des elektrischen Feldes und des Stromflusses erzielt. Das Presswerkzeug ermöglicht es nach einer Ausführungsform, Heizraten bis 1000 K/min zu erreichen. Der Vorteile des FAST Verfahrens im Vergleich zu anderen Verfahren ist die Möglich- keit, durch den gepulsten Gleichstrom als auch die induzierten elektrischen und mag- netischen Felder unterschiedliche Materialien miteinander zu verbinden. Weiterhin führt der gepulste Gleichstrom auch dazu, dass man, z.B. auch durch eine geeignete Wahl der Sinterkammer, zusätzliche Temperaturgradienten hervorrufen kann, welche es weiterhin erleichtern unterschiedliche Materialien miteinander zu verbinden. The method according to the invention comprises the step of sintering, in particular the so-called field-supported sintering or additive methods such as laser or electron beam melting. With the process, which is also referred to as (FAST), at least one permanent-magnetic component having at least one carrier component is compacted to form a mechanically stable gradient material. This is a pressure-assisted sintering process with pulsed direct current in a press tool. For this purpose, the material to be processed is introduced into a sintering chamber and pressed. For heat input, a pulsed current flows directly through the introduced components / materials, which have the concentration profile described above. For electrically conductive materials, a significant increase in the compression rate is achieved by the influence of the electric field and the current flow. The pressing tool makes it possible according to one embodiment, to achieve heating rates up to 1000 K / min. The advantages of the FAST method compared to other methods is the possibility to connect different materials with each other through the pulsed direct current as well as the induced electric and magnetic fields. Furthermore, the pulsed direct current also means that, for example, by a suitable choice of the sintering chamber, additional temperature gradients can be caused, which also make it easier to connect different materials together.
Weitere Vorteile des FAST Verfahrens liegen in dem niedrigen Druck auf der MPa Skala und einer hohen Effektivität mit einer hohen Aufheizgeschwindigkeit von 100 bis 1000 K/min, einer Haltezeit von wenigen Minuten und einer kurzen Abkühlphase, die zu einer Verdichtung des Materials führen. Die hier vorgeschlagene Methode kann für die energieeffiziente Fierstellung erfindungsgemäßer mechanisch stabilen Gradienten- materialien angewendet werden. Further advantages of the FAST method are the low pressure on the MPa scale and a high efficiency with a high heating rate of 100 to 1000 K / min, a holding time of a few minutes and a short cooling phase, which lead to a compression of the material. The method proposed here can be used for the energy-efficient Fierstellung inventive mechanically stable gradient materials.
Zumindest die permanentmagnetische Komponente und die Trägermaterialkompo- nente werden schichtweise in Form von Mischungen unterschiedlicher Konzentration in Pulverform in die Kammer des Presswerkzeugs eingebracht und dort schichtweise vorverdichtet, so dass das gewünschte Konzentrationsprofil aufgebaut wird. Danach wird unter einem uniaxialen Druck von z.B. 10 bis 300 MPa und insbesondere 50 MPa bis 80 MPa in einem Vakuum oder einer Schutzgasatmosphäre auf 600 bis 1900°C, insbesondere 800°C bis 1200°C durch den Stromfluss erhitzt. Im Laufe des FAST Ver- fahrens wird typischerweise eine Spannung von unter 8 V, insbesondere unter 5 V, und ein Strom von 1 kA bis 10 kA gewählt. At least the permanent-magnetic component and the carrier material component are introduced in layers in the form of mixtures of different concentrations in powder form into the chamber of the pressing tool and there precompressed in layers, so that the desired concentration profile is established. Thereafter, under a uniaxial pressure of e.g. 10 to 300 MPa and in particular 50 MPa to 80 MPa in a vacuum or a protective gas atmosphere at 600 to 1900 ° C, in particular 800 ° C to 1200 ° C heated by the flow of current. In the course of the FAST method, a voltage of below 8 V, in particular below 5 V, and a current of 1 kA to 10 kA are typically selected.
Ein weiterer großer Vorteil des FAST-Verfahrens für die Gradientenmaterial-Herstel- lung liegt in der kurzen Prozesszeit begründet. Dies führt zu einer Reduzierung des Kornwachstums im Sinterprozess, wodurch eine Nano- und Mikrostruktur in der Kör- nung des Werkstoffes beibehalten wird. Dies hat positive Auswirkungen auf die me chanischen Eigenschaften des Materials. Another big advantage of the FAST process for gradient material production is the short process time. This leads to a reduction of the grain growth in the sintering process, whereby a nano- and microstructure in the grain of the material is maintained. This has positive effects on the mechanical properties of the material.
Bei der hier vorgeschlagenen Herstellungsmethode entstehen Gradientenmaterialien mit einem Gewichtsanteil von 10 Gew.-% bis 90 Gew.-%, bevorzugt 50 Gew.-% bis 90 Gew.-% der permanentmagnetischen Komponente, relativ zum Gesamtgewicht des Gradientenmaterials. Die Ausgangskomponenten für die Synthese im FAST-Verfahren können in einer Ku- gelmühle zu Pulvermischungen geeigneter Konzentration aufbereitet werden. Dabei können Pulvermischungen mit gestufter Konzentration realisiert werden, z.B. von 100 Gew.% der permanentmagnetischen Komponente abfallend in Schritten (bildend je- weils eine Schichten) von jeweils 10 Gew.% (Konzentrationsgradient) bis zu 0 Gew.% des permanentmagnetischen Komponente und entsprechend gegenläufig ansteigen- der Konzentration der Trägerkomponente. In the production method proposed here, gradient materials having a weight fraction of from 10% by weight to 90% by weight, preferably from 50% by weight to 90% by weight, of the permanent-magnetic component are formed relative to the total weight of the gradient material. The starting components for the synthesis in the FAST process can be prepared in a ball mill to give powder mixtures of suitable concentration. In this case, powder mixtures with a graduated concentration can be realized, for example from 100% by weight of the permanent-magnetic component, decreasing in steps (each forming one layer) of in each case 10% by weight (concentration gradient) up to 0% by weight of the permanent-magnetic component and correspondingly opposite increasing concentration of the carrier component.
In einer Ausgestaltung werden die Schichten vor dem Sintern jeweils in Form von meh- reren Lagen einer Pulvermischung aus jeweils Pulvern enthaltend einerseits die Trä- gerkomponente und andererseits die permanentmagnetische Komponente bereitge- stellt. In dieser Ausgestaltung ändert sich die Konzentration der Trägerkomponente und der permanentmagnetischen Komponente von Schicht zu Schicht entlang der Raumrichtung. In one embodiment, before sintering, the layers are each provided in the form of several layers of a powder mixture of respective powders containing on the one hand the carrier component and on the other hand the permanent-magnetic component. In this embodiment, the concentration of the carrier component and the permanent magnetic component changes from layer to layer along the spatial direction.
In einer bevorzugten Ausgestaltung weisen die Schichten in der Raumrichtung entge- gengesetzt zur von Schicht zu Schicht ansteigenden Konzentration des permanent- magnetischen Materials von Schicht zu Schicht eine abfallende Konzentration der Trä- gerkom ponente auf, abfallend von einer ersten Schicht mit 100% der Trägerkompo- nente. Dies bedeutet, dass die erste Schicht ausschließlich aus der Trägerkomponente besteht bzw. ausschließlich aus dem Trägermaterial besteht, wenn die Trägerkompo- nente ausschließlich aus dem Trägermaterial besteht. Die Konzentration des Träger- materials nimmt in der Raumrichtung ab. In a preferred embodiment, the layers in the spatial direction, opposite to the layer-to-layer concentration of the permanent magnetic material from layer to layer, have a decreasing concentration of the carrier component, sloping from a first layer containing 100% of the carrier component. component. This means that the first layer consists exclusively of the carrier component or consists exclusively of the carrier material if the carrier component consists exclusively of the carrier material. The concentration of the carrier material decreases in the spatial direction.
In einer weiteren Ausgestaltung nimmt die Konzentration des permanentmagnetischen Materials entlang der Raumrichtung zu. In dieser Ausgestaltung beträgt der Anteil an permanentmagnetischem Material am Ende des Gradientenmaterials vorzugsweise 100%. In a further embodiment, the concentration of the permanent magnetic material increases along the spatial direction. In this embodiment, the proportion of permanent magnetic material at the end of the gradient material is preferably 100%.
Auch kleinere oder größere Schritte oder Schritte ungleicher Höhe bzw. ein fast konti- nuierlicher Übergang in Bezug auf den Konzentrationsgradienten sind möglich. We- sentlich ist nur, dass die Konzentration der permanentmagnetischen Komponente in der einen ansteigenden Raumrichtung jeweils nicht abfällt. Eine Schicht kann aus mehreren Lagen des Pulvers bestehen. Die Lagen einer Schicht können auch bereists ihrerseits einen Konzentrationsgradienten aufweisen, können aber auch hinsichtlich der stofflichen Beschaffenheit homogen sein. Das erfindungs- gemäße Gradientenmaterial umfasst zumindest vier Schichten von jeweils zumindest einer permanentmagnetischen Komponente und zumindest einer Trägerkomponente zum Erhalt einer Schichtung, wobei die permanentmagnetische Komponente zumin- dest ein permanentmagnetisches Material und die Trägerkomponente zumindest ein Trägermaterial, das sich von der permanentmagnetischen Komponente unterscheidet, umfasst. Even smaller or larger steps or steps of unequal height or an almost continuous transition with respect to the concentration gradient are possible. It is only essential that the concentration of the permanent-magnetic component does not drop in each case in the one rising spatial direction. A layer may consist of several layers of the powder. The layers of a layer can also bereks have a concentration gradient in their turn, but can also be homogeneous in terms of the material nature. The gradient material according to the invention comprises at least four layers each of at least one permanent-magnetic component and at least one carrier component for obtaining a lamination, wherein the permanent-magnetic component comprises at least one permanent-magnetic material and the carrier component comprises at least one carrier material which differs from the permanent-magnetic component ,
In der Kugelmühle werden die Komponenten zerkleinert und gemischt zu Partikelgrö- ßen im Bereich von Nanometern bis hin zu Mikrometern. Zudem kann durch diesen Prozess auch eine ideale Homogenisierung der Komponentengemische der Zwi- schenschichten erreicht werden. In the ball mill, the components are comminuted and mixed into particle sizes ranging from nanometers to micrometers. In addition, this process can also be used to achieve ideal homogenization of the component mixtures of the intermediate layers.
Die einzelnen Pulvergemische werden dann in der FAST-Kammer übereinanderge- schichtet. Die zumindest vier Schichten werden in der FAST-Kammer vorverdichtet und dann unter einem uniaxialen Druck von 10 MPa bis 300 MPa in einem Vakuum oder einer Schutzgasatmosphäre auf 600°C - 1900°C erhitzt. Im Verlaufe des FAST Verfahrens werden eine Spannung von unter 8 V und ein Strom von 1 kA - 10 kA gewählt. Das Sintern kann in einem externen Magnetfeld erfolgen The individual powder mixtures are then stacked in the FAST chamber. The at least four layers are precompressed in the FAST chamber and then heated to 600 ° C - 1900 ° C under a uniaxial pressure of 10 MPa to 300 MPa in a vacuum or inert gas atmosphere. During the FAST process a voltage of less than 8 V and a current of 1 kA - 10 kA are chosen. The sintering can be done in an external magnetic field
Nach einer Ausgestaltung des Verfahrens werden die eingesetzten Pulver während der Anwendung der FAST Methode zum Erhalt eines festen Körpers in einem elektri- schen oder magnetischen Feld ausgerichtet. According to one embodiment of the method, the powders used are aligned during the application of the FAST method for obtaining a solid body in an electric or magnetic field.
Hierzu besteht die Möglichkeit einen Elektromagneten in die Wand, die die FAST Kam- mer umgibt, oder eine Spule um die Graphitform herum einzubauen, der bei Betrieb ein homogenes Magnetfeld in der Kammer verursacht und so zusätzlich durch Aus- richtung während des Sinterns das Energieprodukt des Permanentmagneten maximie- ren kann. Dies kann insbesondere von Vorteil sein, um das permanentmagnetische Gradientenmaterial nach dem Sinterprozess in einem Arbeitsschritt auszurichten, da die permanentmagnetische Komponente des Gradientenmaterials oberhalb der mate- rialspezifischen Curie-Temperatur ihre ferromagnetischen oder ferrimagnetischen Ei- genschaften verliert, sodass sie oberhalb nur noch paramagnetisch sind. Es ist aber auch möglich, die Ausrichtung des permanentmagnetischen Gradienten- materials nach dem Sintervorgang separat vorzunehmen, bevorzugt ist es jedoch, die Ausrichtung des permanentmagnetischen Gradientenmaterials während des Sinterns, d.h. wenn die Curie-Temperatur zunächst überschritten wurde, und andauernd wenn die Temperatur anschließend wieder unter die die Curie-Temperatur zurückgefallen ist, vorzunehmen. For this purpose, it is possible to install an electromagnet in the wall surrounding the FAST chamber, or a coil around the graphite mold, which in operation causes a homogeneous magnetic field in the chamber and thus additionally by aligning during sintering the energy product of the Permanent magnets can maximize. This may be particularly advantageous for aligning the permanent-magnetic gradient material in a single step after the sintering process, since the permanent-magnetic component of the gradient material loses its ferromagnetic or ferrimagnetic properties above the material-specific Curie temperature, so that they are only paramagnetic above. However, it is also possible to carry out the alignment of the permanent-magnetic gradient material separately after the sintering process, but it is preferred to align the permanent-magnetic gradient material during sintering, ie when the Curie temperature was initially exceeded, and continuously when the temperature subsequently returns under which the Curie temperature has fallen back.
Das erfindungsgemäße Verfahren zur Herstellung eines permanentmagnetischen Gradientenmaterials wird nachgehend anhand eines Ausführungsbeispiels genauer erläutert. The method according to the invention for producing a permanent magnetic gradient material will be explained in more detail below with reference to an exemplary embodiment.
In speziellen Pressformen können zusätzliche Temperaturgradienten hergerufen wer- den. Dies kann beispielsweise genutzt werden, wenn das ferromagnetische Material und das Trägermaterial unterschiedliche Sintertemperaturen besitzen. Durch die Ver- wendung von beispielsweise eines Graphitbehälters in Form eines Kegelstumpfes kann ein zusätzlicher Temperaturgradient hervorgerufen werden. Durch die Kegelform ändert sich die Stromdichte in Abhängigkeit der Position des Kegels und damit die resultierende Temperatur in der Form. Der schmalere Teil des Kegelstumpfes wird eine niedrigere Temperatur besitzen im Vergleich zum Bereich mit dem größeren Durchmesser. In special molds, additional temperature gradients can be obtained. This can be used, for example, if the ferromagnetic material and the carrier material have different sintering temperatures. By using, for example, a graphite container in the shape of a truncated cone, an additional temperature gradient can be produced. Due to the cone shape, the current density changes depending on the position of the cone and thus the resulting temperature in the mold. The narrower part of the truncated cone will have a lower temperature compared to the larger diameter section.
In einer anderen Ausgestaltung wird schrittweise Pulverschicht für Pulverschicht ver- dichtet und FAST-gesintert. In another embodiment, step by step powder layer for powder layer is compressed and FAST-sintered.
Das gesinterte Gradientenmaterial kann als Permanentmagnet eingesetzt werden. Ein Permanentmagnet (auch Dauermagnet) ist ein Magnet aus einem Stück eines ferro- oder ferrimagnetischen Materials, zum Beispiel Legierungen aus Eisen, Cobalt, Nickel oder bestimmten Ferriten. Er hat und behält ein statisches Magnetfeld, ohne dass man wie bei Elektromagneten einen elektrischen Stromfluss benötigt. Permanentmagnete besitzen an ihrer Oberfläche je einen oder mehrere Nord- und Südpol(e). The sintered gradient material can be used as a permanent magnet. A permanent magnet (permanent magnet) is a magnet made of one piece of ferromagnetic or ferrimagnetic material, for example alloys of iron, cobalt, nickel or certain ferrites. He has and retains a static magnetic field, without the need for an electric current flow as with electromagnets. Permanent magnets each have one or more north and south poles (e) on their surface.
Permanentmagnete können durch die Einwirkung eines Magnetfeldes auf ein ferrimag- netisches oder ferromagnetisches Material erzeugt werden. Durch ein abklingendes magnetisches Wechselfeld, Erwärmung oder Stoßeinwirkung können Permanentmag- nete entmagnetisiert werden. Typische Anwendung der erfindungsgemäßen Magnete sind Haftmagnete und Feld- magnete von Gleichstrommotoren, Generatoren, Windkraftgeneratoren, Magnetrons und elektrodynamischen Lautsprechern, Mikrofone oder in Teilchenbeschleunigern als Ablenk- oder Fokussiermagnete in Wigglern und Undulatoren, bzw. Halterungen für solche Vorrichtungen.
Figure imgf000011_0001
Permanent magnets can be generated by the action of a magnetic field on a ferrimagic or ferromagnetic material. A decaying alternating magnetic field, heating or impact can demagnetize permanent magnets. Typical applications of the magnets according to the invention are holding magnets and field magnets of direct current motors, generators, wind power generators, magnetrons and electrodynamic loudspeakers, microphones or in particle accelerators as deflection or focusing magnets in wigglers and undulators or holders for such devices.
Figure imgf000011_0001
Nachfolgend wird das erfindungsgemäße Verfahren an einem Beispiel erläutert, ohne dass die Erfindung auf das Beispiel beschränkt wäre. The method according to the invention will be explained below by way of example, without the invention being restricted to the example.
Eine Schichtung von elf Schichten eines Pulvers variierend von 100 Vol.% Nd2Fei4B hin zu 100 Vol.% rostfreiem Stahl vom Typ 316L nach ASTM-Norm in 10 Vol.% Schrit- ten wurden hergestellt. Hierfür wurden die benötigten Pulvermischungen bzw. die sor- tenreinen Pulver (in den Endlagen) zuvor in der Kugelmühle in Hexan für 2 h bei 200 rpm mit einem Kugel-zu-Pulver-Gewichts-Verhältnis von 10: 1 gemahlen und miteinan- der vermengt. Die Pulvermischungen bzw. sortenreinen Pulver wurden dann überei- nander in einem Graphitbehälter (Kammer des Presswerkzeuges) mit einem Innen- durchmesser von 20 mm geschichtet und der Behälter mit den Graphitstempeln an beiden Enden in der FAST-Kammer platziert. Das Pulver wurde anschließend in dem Graphitbehälter in der FAST-Kammer unter Vakuum einem Anfangsdruck von 10 MPa ausgesetzt (Phase 1 ). In den folgenden 6 min wurde ein Druck von 80 MPa stetig aufgebaut (Phase 2). Der eingesetzte gepulste Gleichstrom für das FAST Verfahren betrug bis zu 1 ,6 kA und die Spannung bis zu 5 V und variierte je nach Temperatur während des Sintervorganges. Zunächst wurde die Probe in einem ersten Heizvor- gang auf 420°C (Phase 3) gebracht. Dieser Schritt ist aus technischen Gründen not- wendig, da das verwendete Pyrometer bei 400°C zu arbeiten beginnt. Der Körper wurde mit einer Heizrate von 100 K/min auf eine Temperatur von 800°C erhitzt (Phase 4). Die Haltezeit des Sintervorgangs bei 800°C betrug 5 min (Phase 5). Der Heizvor- gang beinhaltend das feldgestützte Sintern dauerte insgesamt für 10 min an. Danach wurde der Strom abgeschaltet aber der Druck auf den Körper beibehalten (Phase 6). Aus der Schichtung von Pulvern entstand ein Körper. Nachdem der Sintervorgang be- endet war, wurde der Körper durch Sandbestrahlen von etwaigen Graphitrückständen befreit und erhalten wurde das Gradientenmaterial. Die Erfindung bzw. die nach den Beispielen erhaltenen Materialien sind weiter anhand nachstehender Figuren erläutert. Es zeigen: A stack of eleven layers of a powder varying from 100 vol.% B 4 Nd2Fei, to 100 vol.% Stainless steel type 316L per ASTM standard in 10 vol.% Were prepared Schrit- th. For this purpose, the required powder mixtures or the pure powders (in the end positions) were previously ground in a ball mill in hexane for 2 h at 200 rpm with a ball to powder weight ratio of 10: 1 and mixed together , The powder blends were then layered together in a graphite container (chamber of the press tool) with an inside diameter of 20 mm and the container with the graphite punches placed at both ends in the FAST chamber. The powder was then subjected to an initial pressure of 10 MPa in the graphite container in the FAST chamber under vacuum (phase 1). In the following 6 min, a pressure of 80 MPa was steadily built up (phase 2). The pulsed direct current used for the FAST process was up to 1.6 kA and the voltage up to 5 V and varied depending on the temperature during the sintering process. First, the sample was brought to 420 ° C (phase 3) in a first heating process. This step is necessary for technical reasons, since the pyrometer used starts working at 400 ° C. The body was heated at a heating rate of 100 K / min to a temperature of 800 ° C (Phase 4). The holding time of the sintering process at 800 ° C was 5 min (phase 5). The heating process, including field-supported sintering, lasted for a total of 10 minutes. Thereafter, the power was turned off but the pressure on the body was maintained (phase 6). The layering of powders produced a body. After the sintering process was completed, sandblasting was used to free the body of any graphite residue and to obtain the gradient material. The invention or the materials obtained according to the examples are further explained with reference to the following figures. Show it:
Fig. 1 : Zeitlicher Verlauf des Sintervorgangs;  Fig. 1: Time course of the sintering process;
Fig. 2: Lichtmikroskopische Aufnahme eines Neodym-Eisen-Bor / Stahl Gradienten- materials;  FIG. 2: optical micrograph of a neodymium-iron-boron / steel gradient material; FIG.
Fig. 3: XRD-Diffraktogramme von 7 beispielhaften Schichten des Gradienten;  Fig. 3: XRD diffractograms of 7 exemplary layers of the gradient;
Fig. 4: Phasenanteile der beitragenden Hauptphasen in den 1 1 Schichten des Gradi- entenmaterials;  FIG. 4: Phase components of the contributing main phases in the 1 1 layers of the gradient material; FIG.
Fig. 5: Gitterparameter der beitragenden Hauptphasen in den 1 1 Schichten des Gra- dientenmaterials;  FIG. 5: lattice parameters of the contributing main phases in the 1 1 layers of the gradient material; FIG.
Fig. 6: Thermische Ausdehnung exemplarischer Zusammensetzungen in Abhängig- keit von der Temperatur.  FIG. 6: Thermal expansion of exemplary compositions as a function of the temperature. FIG.
Der Ablauf des zuvor beschriebenen Vorgangs ist in Fig. 1 graphisch dargestellt. The sequence of the process described above is shown graphically in FIG.
Der Sintervorgang wird im Wesentlichen durch die oben im Text genannten 6 Phasen beschrieben. Das erhaltene gesinterte Gradientenmaterials aus Neodym-Eisen-Bor / Stahl ist in Fig. 2 dargestellt. The sintering process is essentially described by the 6 phases mentioned above in the text. The obtained neodymium-iron-boron / steel sintered gradient material is shown in FIG.
Die relativen Dichten des Neodymeisenbors, des rostfreien Stahls als auch jeder der 9 Zwischenschichten liegen bei über 98% der theoretischen Dichte. Die Dichten der einzelnen Schichten wurden an separat gesinterten Probestücken mit Hilfe des Archi- medischen Prinzips bestimmt. Der stufenweise Übergang von Neodymeisenbor (links) zu Stahl (rechts) ist in insgesamt 9 Zwischenschritten zu erkennen. The relative densities of the neodymium iron, stainless steel and each of the 9 interlayers are above 98% of theoretical. The densities of the individual layers were determined on separately sintered specimens using the Archimedian principle. The gradual transition from Neodymeisenbor (left) to steel (right) can be seen in a total of 9 intermediate steps.
Die Struktur entlang des Gradienten ist anhand der Röntgendiffraktogramme beispiel- haft an 7 Schichten in Fig. 3 dargestellt. The structure along the gradient is shown by way of example on 7 layers in FIG. 3 on the basis of the X-ray diffractograms.
Die Phasenzusammensetzung kann beispielsweise mit Hilfe der XRD Daten aus der Rietveld-Analyse gewonnen werden. Dabei sind die Streustärken der einzelnen Pha- sen als auch die gesamte Intensität der einzelnen Phasen in den Diffraktogrammen zu berücksichtigen. Die Phasenzusammensetzung des Gradientenmaterials ist in Fig. 4 dargestellt.  The phase composition can be obtained, for example, using the XRD data from the Rietveld analysis. The scattering intensities of the individual phases as well as the total intensity of the individual phases in the diffractograms must be taken into account. The phase composition of the gradient material is shown in FIG.
Es wurde ermittelt, dass nach dem Sintervorgang die beitragenden Hauptphasen Ne- odymeisenbor, Stahl in Austenitstruktur als auch Eisen in der alpha-Phase (Ferrit) vor- lagen. Die Ferritphase trat aufgrund einer teilweisen Zersetzung des Neodymeisenbors auf. Zusätzlich entstehen bei der Zersetzung noch eine neodymreiche als auch eine bor- reiche Phase, die jedoch nur einen geringen Phasenanteil von weniger als 5 Vol% im Maximum aufwiesen, sodass sie in Fig. 4 nicht mit berücksichtigt wurden. Es ist hierbei zu erwähnen, dass das Auftreten des Ferrites sich nicht negativ auf die magnetischen Eigenschaften des Neodymeisenbors ausübt. It was found that after the sintering process, the main contributing phases were neodymium iron, austenitic steel and iron in the alpha phase (ferrite). The ferrite phase occurred due to partial decomposition of the neodymium iron. In addition, a neodymium-rich as well as a boron-rich phase is formed during the decomposition, but these have only a small phase fraction of less than 5% by volume at maximum, so that they were not taken into account in FIG. 4. It should be noted that the appearance of the ferrite does not adversely affect the magnetic properties of the neodymium iron.
Die Gitterparameter für die Flauptphasen, Fig. 5, zeigen entlang der 1 1 Schichten leichte Veränderungen, wobei die größten Veränderungen an dem Übergang von der anfänglichen reinen Neodymeisenborphase zur nächsten Schicht auftreten. Diese Un- terschiede in den Gitterparametern weisen auf internen Stress im Material hin, was die Stabilität des Gradienten reduzieren kann und auch zu Rissen an diesen Kanten füh- ren kann. Unter der Annahme des Flook'schen Gesetzes kann man die Veränderungen der Gitterkonstanten entlang der Position des Gradienten in einen internen Stress um wandeln und so zeigen, dass für den beschriebenen Gradienten der maximal auftre- tende Stress unterhalb der Zugfestigkeit der beitragenden Phasen liegt, sodass der Gradient mechanisch stabil ist. The lattice parameters for the main phases, Figure 5, show slight changes along the 1 l layers, with the largest changes occurring at the transition from the initial pure neodymium iron borate phase to the next layer. These differences in the lattice parameters indicate internal stress in the material, which can reduce the stability of the gradient and also lead to cracks at these edges. Based on Flook's law, the changes in the lattice constants along the position of the gradient can be converted into an internal stress and thus show that for the described gradient the maximum stress occurring lies below the tensile strength of the contributing phases, so that the Gradient is mechanically stable.
Die thermische Ausdehnung einzelner Gradientenschichten ist in Fig. 6 graphisch dar- gestellt. Diese wurden dilatometrisch untersucht. Dabei wurde die thermische Ausdeh- nung von Proben aus 7 Schichten des hergestellten Neodym-Eisen-Bor / Stahl Gradi- entenmaterials bei ansteigender Temperatur bestimmt. Das Ergebnis verdeutlicht, dass die Schichten mit lediglich Neodym-Eisen-Bor vergleichen mit der Schicht aus lediglich Stahl einen sehr unterschiedlichen thermischen Ausdehnungskoeffizienten aufweisen. Durch das Einführen von Zwischenschichten kann die große Differenz im Übergang von der einen zur nächsten Schicht minimiert werden, was ebenfalls einen positiven Einfluss auf den Sinterprozess und die Gesamtstabilität des Gradientenma- terials hat. The thermal expansion of individual gradient layers is shown graphically in FIG. 6. These were examined by dilatometry. The thermal expansion of samples from 7 layers of the produced neodymium-iron-boron / steel gradient material was determined with increasing temperature. The result clarifies that the layers with only neodymium-iron-boron compare with the layer of steel only have a very different coefficient of thermal expansion. By introducing intermediate layers, the large difference in the transition from one layer to the next can be minimized, which also has a positive influence on the sintering process and the overall stability of the gradient material.

Claims

Patentansprüche claims
1. Verfahren zur Herstellung eines gesinterten Gradientenmaterials umfassend 1. A method for producing a sintered gradient material comprising
- Bereitstellen von zumindest vier Schichten von jeweils zumindest einer perma- nentmagnetischen Komponente und zumindest einer Trägerkomponente zum Erhalt einer Schichtung, wobei die permanentmagnetische Komponente zumin- dest ein permanentmagnetisches Material und die Trägerkomponente zumin- dest ein Trägermaterial, das sich von der permanentmagnetischen Kompo- nente unterscheidet, umfasst, und  Providing at least four layers each of at least one permanent-magnetic component and at least one carrier component for obtaining a lamination, wherein the permanent-magnetic component is at least one permanent-magnetic material and the carrier component is at least one carrier material which differs from the permanent-magnetic component distinguishes, includes, and
- Aussetzen der Schichtung einem Sintern, insbesondere einem feldgestütztem Sintern, zum Erhalt des gesinterten Gradientenmaterials,  Subjecting the layer to sintering, in particular field-supported sintering, to obtain the sintered gradient material,
wobei die Schichtung in zumindest einer Raumrichtung eine sich ändernde Konzent- ration des permanentmagnetischen Materials aufweist. wherein the layering in at least one spatial direction has a changing concentration of the permanent magnetic material.
2. Verfahren nach Anspruch 1 , wobei zumindest ein Material der permanentmagneti- schen Komponente stofflich unterschiedlich zu dem Material / den Materialien der Trä- gerkomponente ist. 2. The method of claim 1, wherein at least one material of the permanent magnetic component is materially different from the material (s) of the carrier component.
3. Verfahren nach einem der vorhergehenden Ansprüche, wobei das Trägermaterial nicht-permanentmagnetisch und/oder paramagnetisch ist, wobei insbesondere die Trägerkomponente aus dem Trägermaterial besteht. 3. The method according to any one of the preceding claims, wherein the carrier material is non-permanent magnetic and / or paramagnetic, wherein in particular the carrier component consists of the carrier material.
4. Verfahren nach einem der vorhergehenden Ansprüche, wobei die Schichten vor dem Sintern jeweils in Form von mehreren Lagen einer Pulvermischung aus jeweils Pulvern enthaltend einerseits die Trägerkomponente und andererseits die permanent- magnetische Komponente bereitgestellt werden mit in der Raumrichtung von Schicht zu Schicht sich gegenläufig ändernder Konzentration der Trägerkomponente und der permanentmagnetischen Komponente. 4. The method according to any one of the preceding claims, wherein the layers are provided before sintering in the form of several layers of a powder mixture of each powder containing on the one hand the carrier component and on the other hand, the permanent magnetic component with in the spatial direction from layer to layer in opposite directions Concentration of the carrier component and the permanent magnetic component.
5. Verfahren nach einem der vorhergehenden Ansprüche, wobei für die Schichten in der Raumrichtung entgegengesetzt zur von Schicht zu Schicht ansteigenden Konzent- ration des permanentmagnetischen Materials sich von Schicht zu Schicht eine abfal- lende Konzentration der Trägerkomponente ergibt, abfallend von einer ersten Schicht mit 100 Gew.% der Trägerkomponente. 5. The method according to claim 1, wherein, for the layers in the spatial direction opposite to the concentration of the permanent magnetic material increasing from layer to layer, a decreasing concentration of the carrier component results from layer to layer, decreasing from a first layer having 100 % By weight of the carrier component.
6. Verfahren nach einem der vorhergehenden Ansprüche, wobei die Schichten in der Raumrichtung von Schicht zu Schicht eine ansteigende Konzentration des permanent- magnetischen Materials zeigen, wobei die letzte Schicht zu 100 Gew.% das perma- nentmagnetische Material aufweist. 6. A method according to any one of the preceding claims, wherein the layers in the spatial direction from layer to layer show an increasing concentration of the permanent magnetic material, the last layer comprising up to 100% by weight of the permanent magnetic material.
7. Verfahren nach Anspruch 5 oder 6, wobei am anderen Ende bezogen auf die zu- mindest eine Raumrichtung 100 Gew.% permanentmagnetische Komponente vorliegt. 7. The method of claim 5 or 6, wherein at the other end with respect to the at least one spatial direction 100 wt.% Permanent magnetic component is present.
8. Verfahren nach einem der vorhergehenden Ansprüche, wobei die permanentmag- netische(n) Komponente(n) und/oder die Trägerkomponente(n) vor dem Sintern in der Schichtung partikulär in Form eines Pulvers vorliegen. 8. The method according to any one of the preceding claims, wherein the permanent magnetic (s) component (s) and / or the carrier component (s) before sintering in the stratification particulate in the form of a powder.
9. Verfahren nach einem der vorhergehenden Ansprüche, wobei die Schichtung meh- rere Schichten aufweist, die jeweils aus Pulvermischungen umfassend die permanent- magnetische^) Komponente(n) und die Trägerkomponente(n) mit gestufter Konzent- ration zumindest der permanentmagnetische(n) Komponente(n) hergestellt sind. 9. Method according to one of the preceding claims, wherein the layering has several layers, each consisting of powder mixtures comprising the permanent magnetic component (s) and the carrier component (s) with graded concentration at least the permanent-magnetic (n) Component (s) are made.
10. Verfahren nach einem der vorhergehenden Ansprüche, wobei die Schichtung 5 bis 20 Schichten und insbesondere bevorzugt 6 bis 12 Schichten umfasst. 10. The method according to any one of the preceding claims, wherein the layering comprises 5 to 20 layers and more preferably 6 to 12 layers.
1 1 . Verfahren nach einem der vorhergehenden Ansprüche, wobei das Gradientenma- terial magnetisch während des Sinterns ausgerichtet wird. 1 1. Method according to one of the preceding claims, wherein the Gradientenma- material is magnetically aligned during sintering.
12. Verfahren nach einem der vorhergehenden Ansprüche, wobei die permanentmag- netische Komponente zu 10 Gew.-% bis 90 Gew.- %, bevorzugt 50 Gew.-% bis 90 Gew.-% im Gradientenmaterial enthalten ist. 12. The method according to any one of the preceding claims, wherein the permanent magnetic component to 10 wt .-% to 90% by weight, preferably 50 wt .-% to 90 wt .-% is contained in the gradient material.
13. Verfahren einem der vorhergehenden Ansprüche, wobei die permanentmagneti- sche Komponente mindestens eine Seltenerde umfasst, insbesondere Neodymeisen- bor, Samarium-Cobalt oder Samarium-Eisen-Stickstoff ist oder umfasst, bevorzugt Ne- odymeisenbor. 13. A process as claimed in one of the preceding claims, wherein the permanent-magnetic component comprises or comprises at least one rare earth, in particular neodymium iron, samarium cobalt or samarium iron nitrogen, preferably neodymium iron boron.
14. Verfahren einem der vorhergehenden Ansprüche, wobei das Trägermaterial para- magnetisch ist und vorzugsweise Eisen-, Nickel und/oder Cobaltlegierungen ein- schließlich metallischer Gläser umfasst. 14. A process as claimed in any one of the preceding claims, wherein the support material is paramagnetic and preferably comprises iron, nickel and / or cobalt alloys, including metallic glasses.
15. Verfahren einem der vorhergehenden Ansprüche, wobei das Sintern bei einer Temperatur von größer 400 °C erfolgt, bevorzugt bei größer 600 °C. 15. The method of any one of the preceding claims, wherein the sintering is carried out at a temperature of greater than 400 ° C, preferably at greater than 600 ° C.
16. Gesintertes Gradientenmaterial hergestellt mit einem Verfahren nach einem der Ansprüche 1 bis 15. 16. Sintered gradient material produced by a method according to one of claims 1 to 15.
17. Verwendung eines gesinterten Gradientenmaterials nach Anspruch 16 zur Befes- tigung eines Magneten, vorzugsweise in einem Generator oder einem Motor. 17. Use of a sintered gradient material according to claim 16 for fastening a magnet, preferably in a generator or a motor.
18. Verwendung nach Anspruch 17, wobei eine erste Schicht des gesinterten Gradi- entenmaterials 100 Gew.% Trägermaterial aufweist und mit dem Material identisch o- der diesem ähnlich ist, mit dem das gesinterte Gradientenmaterial an einem Ende der Raumrichtung in Berührung steht und am anderen Ende der Raumrichtung, wo die permanentmagnetische Komponente überwiegt, das gesinterte Gradientenmaterial dem Magneten zugewandt ist, bzw. mit diesem in Berührung steht. 18. Use according to claim 17, wherein a first layer of the sintered gradient material has 100% by weight of carrier material and is identical or similar to the material with which the sintered gradient material is in contact at one end of the spatial direction and at the other End of the spatial direction, where the permanent magnetic component predominates, the sintered gradient material faces the magnet, or is in contact therewith.
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