EP0243641A1 - Process for manufacturing a permanent-magnet material from powder - Google Patents
Process for manufacturing a permanent-magnet material from powder Download PDFInfo
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- EP0243641A1 EP0243641A1 EP87103787A EP87103787A EP0243641A1 EP 0243641 A1 EP0243641 A1 EP 0243641A1 EP 87103787 A EP87103787 A EP 87103787A EP 87103787 A EP87103787 A EP 87103787A EP 0243641 A1 EP0243641 A1 EP 0243641A1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
- C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
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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
- B22F3/006—Amorphous articles
- B22F3/007—Amorphous articles by diffusion starting from non-amorphous articles prepared by powder metallurgy
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/10—Alloys containing non-metals
- C22C1/1084—Alloys containing non-metals by mechanical alloying (blending, milling)
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- 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
- H01F1/0576—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 pressed, e.g. hot working
Definitions
- the invention relates to a method for producing a permanent magnet material of a metal-metal-metalloid system, in which the at least one powdered starting component of the metals mixed together with a powdered component made of elemental boron or a boron compound or alloy, optionally compacted and finally subjected to an annealing treatment to form the permanent magnet material.
- a method for producing a permanent magnet material of a metal-metal-metalloid system in which the at least one powdered starting component of the metals mixed together with a powdered component made of elemental boron or a boron compound or alloy, optionally compacted and finally subjected to an annealing treatment to form the permanent magnet material.
- Such a method is e.g. in the publication "Journal of Applied Physics", Vol. 57, No. 1, April 15, 1985, pages 4149 to 4151.
- the object of the present invention is therefore to improve the method of the type mentioned in such a way that it can be used in a simple manner to produce a powder of the material system mentioned, which has an extremely fine microstructure similar to that of rapidly quenched material and, if appropriate, also known methods can be compacted into a body made of magnetically oriented material.
- powder mixture from the starting components is first subjected to a grinding process in the manner of mechanical alloying, a mixed powder of the at least one metallic starting component being formed with embedded or attached fine particles of the boron component.
- powders should also include bodies, particles or particles such as Filings can be understood that only have powder-like shapes.
- M1M2B hard magnetic metal-metal-boron
- M2 is selected from the group of late transition metals that can be found in the periodic table of the elements.
- M1 is a rare earth metal or an actinide.
- the corresponding metallic starting components should be in powder form or at least have a powder-like appearance, whereby they can preferably be in elemental form or, if appropriate, also in the form of alloys or compounds.
- M1 and M2 can in particular be the metals neodymium (Nd) and iron (Fe). Accordingly, the ternary alloy NdFeB is assumed below as an exemplary embodiment.
- powders of the two metallic starting components Fe and Nd and B powder together with hardened steel balls are first placed in a suitable grinding bowl, the ratio of the three powder types of this powder mixture being determined by the predetermined resulting atomic concentration of the powder to be produced from these powders Material is determined.
- the quantitative ratio of the three elementary types of powder of this powder mixture can be chosen so that the composition Nd15Fe77B8 is formed after a diffusion reaction to be carried out.
- the proportion of Nd can be between 10 and 20 atomic% and that of B between 2 and 10 atomic%, with the Fe fraction making up the rest.
- the size of the individual powders can be arbitrary; however, a similar size distribution of the two metallic starting components involved in a range between 5 ⁇ m and 1 mm, in particular between 20 ⁇ m and 0.5 mm, is advantageous.
- Fe powders with a size of the powder particles below 40 ⁇ m and Nd filings with a size of less than 0.5 mm are used.
- the B powder should be as fine as possible, the particles advantageously being less than 10 ⁇ m, preferably less than 1 ⁇ m. In particular, this can be largely amorphous B powder.
- the grinding speed and the ratio of the steel balls to the amount of powder are further parameters that determine the necessary grinding time.
- the mill's steel grinding bowl is kept under protective gas such as argon or helium and only opened again after the grinding process has ended.
- finely layered powder grains which consist of Fe and Nd layers, form after only about 2 hours of meal.
- the B-particles are embedded or attached to the Fe / Nd interfaces as well as in the elemental metals.
- this layer structure becomes ever finer until it can no longer be resolved by light microscopy after about 10 to 30 hours of eating.
- This then gave rise to powder particles of a mixed powder which consist of an intimate mixture of Fe and Nd with embedded or attached B-particles, the size of which is significantly smaller than 1 ⁇ m.
- the powder particles themselves have a diameter of approximately 1 to 200 ⁇ m. In X-ray examinations of this mixed powder, only strongly broadened intensity maxima of Fe can be seen. There is no evidence of the formation of amorphous FeNd or an FeNd phase.
- the subsequent reaction annealing must also take place under protective gas or under vacuum.
- the annealing can be carried out at one or more different temperatures. A continuous change in temperature is also possible.
- an annealing treatment of, for example, 1 hour at 600 ° C.
- the desired Nd2Fe1 flexB phase is formed by a diffusion reaction and has excellent hard magnetic properties.
- the reacted powder shows a coercive force of over 10 kOe after embedding in plastic.
- the real advantage of the method according to the invention is that an extremely intimate through with the grinding process in the manner of mechanical alloying mix of the elements involved. In the subsequent diffusion reaction, therefore, only very short diffusion paths are required, which can be overcome at relatively low temperatures or short times. This makes it possible to achieve an extremely fine microstructure of the Nd2Fe14B phase, which corresponds, for example, to that of rapidly quenched material.
- the magnetic hardening of this material is carried out accordingly by Blochwand anchoring.
- a particular advantage is that the annealing can take place at temperatures below 640 ° C, the lowest eutectic temperature in the binary FeNd phase diagram. Above this temperature, a rapid grain enlargement would occur due to the presence of a liquid phase. For the ternary hard magnetic material mentioned, a reaction temperature between approximately 400 ° C. and 640 ° C. appears most suitable.
- annealing at higher temperatures e.g. at 900 ° C for one hour also at good values for the coercive force.
- the powder formed is relatively coarse-grained, has foreign phases at the grain boundaries and shows a magnetic hardening mechanism characterized by the blocked domain nucleation. It thus resembles the material which is produced in accordance with the aforementioned EP-A1 and can then be further processed in a known manner to form an anisotropic magnet.
- the temperature treatments known from EP-A1 can also be used advantageously for this.
- this powder can e.g. can be used as a plastic-bonded isotropic magnet.
- composition of the material on which the exemplary embodiment is based can deviate from the stoichiometric composition Nd2Fe14B during the weighing in, approximately in the manner which is customary for the processes known from the publications mentioned.
- one or more of the three elements involved can be partially or optionally even completely substituted by other elements.
- Nd can be partially or completely replaced by an element of the heavy rare earths, such as Dy or Tb, for example.
- Dy or Tb for example.
- Fe another element of the late transition metals, for example Co or Ni, can be provided.
- a partial replacement by Al is also possible.
- B can be partially substituted by another metalloid.
- the starting powders used depend on the desired compositions.
- the diffusion process it is particularly advantageous for thermodynamic reasons if elemental powders are used, since the driving force for the diffusion reaction is greatest here.
- amorphous B powder is particularly advantageous.
- the elements involved can also be in the form of pre-alloyed powder, for example as Fe2B or as an NdFe phase or an NdFe alloy with 20 to 40 atomic% Fe can be added.
- pre-alloyed powder for example as Fe2B or as an NdFe phase or an NdFe alloy with 20 to 40 atomic% Fe can be added.
- metastable phases are again preferred to the equilibrium phases for the thermodynamic reasons mentioned.
- At least two metallic starting components M 1 and M 2 are provided in powder form, each of these two components consisting of a metallic (chemical) element or of an alloy or compound with this element. If necessary, it is also possible to start from only a single powdery alloy of the two starting metals M1 and M2; i.e., the alloy M1-M2 alone then provides the two metallic components of the permanent magnet material to be produced. In the case of Nd2Fe14B this would be the alloy Nd16Fe84 in powder form, which together with the B powder forms the powder mixture to be ground.
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Abstract
Mit dem Verfahren ist ein Dauermagnetwerkstoff eines Metall-Metall-Metalloid-Systems herzustellen, bei dem die mindestens eine pulverförmige Ausgangskomponente der Metalle zusammen mit einer pulverförmigen Komponente aus elementarem Bor oder aus einer Bor-Verbindung oder -Legierung vermischt, gegebenenfalls kompaktiert und schließlich einer Glühbehandlung zur Ausbildung des Dauermagnetwerkstoffes ausgesetzt wird. Um auf einfache Weise ein Pulver des genannten Stoffsystems mit äußerst feiner Mikrostruktur herstellen zu können, ist erfindungsgemäß vorgesehen, daß das Pulvergemisch aus den Ausgangskomponenten zunächst einem Mahlprozeß nach Art des mechanischen Legierungs unterzogen wird, wobei ein Mischpulver der mindestens einen metallischen Ausgangskomponente mit ein- oder angelagerten feinen Partikeln der Bor-Komponente ausgebildet wird. The method is used to produce a permanent magnet material of a metal-metal-metalloid system, in which the at least one powdered starting component of the metals is mixed with a powdered component made from elemental boron or from a boron compound or alloy, optionally compacted and finally an annealing treatment is exposed to the formation of the permanent magnet material. In order to be able to produce a powder of the material system mentioned with an extremely fine microstructure in a simple manner, it is provided according to the invention that the powder mixture from the starting components is first subjected to a milling process in the manner of a mechanical alloy, a mixed powder of the at least one metallic starting component having an input or attached fine particles of the boron component is formed.
Description
Die Erfindung bezieht sich auf ein Verfahren zur Herstellung eines Dauermagnetwerkstoffes eines Metall-Metall-Metalloid-Systems, bei dem die mindestens eine pulverförmige Ausgangskomponente der Metalle zusammen mit einer pulverförmigen Komponente aus elementarem Bor oder aus einer Bor-Verbindung oder -Legierung vermischt, gegebenenfalls kompaktiert und schließlich einer Glühbehandlung zur Ausbildung des Dauermagnetwerkstoffes ausgesetzt wird. Ein derartiges Verfahren ist z.B. in der Veröffentlichung "Journal of Applied Physics", Vol. 57, No. 1, 15.4.1985, Seiten 4149 bis 4151 beschrieben.The invention relates to a method for producing a permanent magnet material of a metal-metal-metalloid system, in which the at least one powdered starting component of the metals mixed together with a powdered component made of elemental boron or a boron compound or alloy, optionally compacted and finally subjected to an annealing treatment to form the permanent magnet material. Such a method is e.g. in the publication "Journal of Applied Physics", Vol. 57, No. 1, April 15, 1985, pages 4149 to 4151.
Seit einiger Zeit sind neue Dauermagnetwerkstoffe von Metall-Metall-Metalloid-Systemen bekannt, die hinsichtlich der wichtigsten hartmagnetischen Größe, des Energieproduktes, alle bisher bekannten Materialien weit übertreffen. Bevorzugte Werkstoffe dieser Systeme haben im wesentlichen die Zusammensetzung Nd₂Fe₁₄B, wobei eine partielle Substitution der genannten Elemente oder leichte Abweichungen von der Stöchiometrie dieser tetragonalen Phase möglich sind, um so die Mikrostruktur der Materialien zu optimieren.For some time now, new permanent magnet materials of metal-metal-metalloid systems have been known which, in terms of the most important hard magnetic size, the energy product, far exceed all previously known materials. Preferred materials of these systems essentially have the composition Nd₂Fe₁₄B, partial substitution of the elements mentioned or slight deviations from the stoichiometry of this tetragonal phase being possible in order to optimize the microstructure of the materials.
Für eine großtechnische Herstellung derartiger Dauermagnetwerkstoffe kommen insbesondere zwei Verfahren zur Anwendung. Gemäß dem aus der EP 0 126 802 A1 bekannten Verfahren wird zunächst eine Legierung der gewünschten Zusammensetzung erschmolzen, anschließend zu feinem Pulver zerkleinert, in einem Magnetfeld magnetisch ausgerichtet und durch eine Druck- und Sinterbehandlung kompaktiert. Bei einem weiteren, aus der EP O 144 112 A1 bekannten Verfahren wird zunächst ein Zwischenprodukt durch schnelles Abschrecken aus der Schmelze der Ausgangskomponenten hergestellt, das dann durch Heißpressen kompaktiert und dann in einem weiteren Verfahrensschritt, dem sogenannten "Die-Upsetting" in der magnetischen Vorzugsrichtung ausgerichtet wird (vgl. z.B. "Appl. Phys. Lett.", Vol. 46, No. 8, 15.4.1985, Seiten 790 und 791). Materialien, die nach diesen beiden Verfahren hergestellt wurden, unterscheiden sich vor allem hinsichtlich ihrer Mikrostruktur. Während sich bei dem aus der EP-A1 bekannten Verfahren eine relativ grobe Kornstruktur mit mehreren Fremdphasen einstellt, zeichnen die sich nach dem zweiten Verfahren schnell abgeschreckten Proben durch eine äußerst feine Kornstruktur aus, die hier die Verankerung der Blochwände, der Träger der Ummagnetisierung, bewirkt.Two methods are used in particular for large-scale production of such permanent magnet materials. According to the method known from EP 0 126 802 A1, an alloy of the desired type is first of all The composition melted, then crushed into fine powder, magnetically aligned in a magnetic field and compacted by a pressure and sintering treatment. In a further method known from EP O 144 112 A1, an intermediate product is first produced by rapid quenching from the melt of the starting components, which is then compacted by hot pressing and then in a further process step, the so-called "die-upsetting" in the magnetic preferred direction is aligned (see, for example, "Appl. Phys. Lett.", Vol. 46, No. 8, April 15, 1985, pages 790 and 791). Materials that were manufactured using these two processes differ primarily in terms of their microstructure. While a relatively coarse grain structure with several foreign phases occurs in the method known from EP-A1, the samples which are quickly quenched by the second method are distinguished by an extremely fine grain structure, which here causes the Bloch walls, the carriers of the magnetic reversal, to be anchored .
Neben diesen beiden Verfahren ist zur Herstellung von Dauermagnetwerkstoffen aus der eingangs genannten Veröffentlichung "J.Appl.Phys." bekannt, als Ausgangskomponenten Fe-, Fe₂B- und Nd-Pulver zu verwenden, die anschließend kompaktiert und gesintert werden. Hierbei bildet sich die gewünschte Phase durch Diffusion aus. Um ein magnetisch anisotropes Material zu erhalten, muß jedoch dieses Sintermaterial anschließend wieder zerkleinert und nach magnetischer Ausrichtung erneut kompaktiert und gesintert werden. Somit ist dieses bekannte Verfahren zur Herstellung von Dauermagnetwerkstoffen mit magnetischer Anisotropie verhältnismäßig aufwendig.In addition to these two processes, the manufacture of permanent magnet materials from the publication "J.Appl.Phys." known to use as starting components Fe, Fe₂B and Nd powder, which are then compacted and sintered. The desired phase is formed by diffusion. In order to obtain a magnetically anisotropic material, however, this sintered material must then be comminuted again and, after magnetic alignment, be compacted and sintered again. This known method for producing permanent magnet materials with magnetic anisotropy is therefore relatively complex.
Aufgabe der vorliegenden Erfindung ist es deshalb, das Verfahren der eingangs genannten Art dahingehend zu verbessern, daß mit ihm sich auf einfache Weise ein Pulver des genannten Stoffsystems herstellen läßt, das eine äußerst feine Mikrostruktur ähnlich der von schnell-abgeschrecktem Material besitzt und sich gegebenenfalls mit an sich bekannten Verfahren zu einem Körper aus magnetisch ausgerichtetem Material kompaktieren läßt.The object of the present invention is therefore to improve the method of the type mentioned in such a way that it can be used in a simple manner to produce a powder of the material system mentioned, which has an extremely fine microstructure similar to that of rapidly quenched material and, if appropriate, also known methods can be compacted into a body made of magnetically oriented material.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß das Pulvergemisch aus den Ausgangskomponenten zunächst einem Mahlprozeß nach Art des mechanischen Legierens unterzogen wird, wobei ein Mischpulver der mindestens einen metallischen Ausgangskomponente mit ein- oder angelagerten feinen Partikeln der Bor-Komponente ausgebildet wird. Unter Pulvern sollen dabei ganz allgemein auch Körper, Partikel oder Teilchen wie z.B. Feilspäne verstanden werden, die nur pulverähnliche Formen haben.This object is achieved in that the powder mixture from the starting components is first subjected to a grinding process in the manner of mechanical alloying, a mixed powder of the at least one metallic starting component being formed with embedded or attached fine particles of the boron component. In general, powders should also include bodies, particles or particles such as Filings can be understood that only have powder-like shapes.
Die mit dieser Ausbildung des Verfahrens verbundenen Vorteile sind dann insbesondere darin zu sehen, daß das so erhaltene Mischpulver sich ohne weiteres in bekannter Weise kompaktieren und einer Glühbehandlung bei verhältnismäßig niedriger Temperatur zur Ausbildung der gewünschten hartmagnetischen Phase unterziehen läßt. Ein vorhergehender Sinter- oder Schmelzprozeß mit anschließender Zerkleinerung des Materials ist also nicht erforderlich. Dennoch lassen sich mit dem Mahlprozeß extrem feine Pulver erhalten.The advantages associated with this embodiment of the method are then to be seen in particular in the fact that the mixed powder obtained in this way can easily be compacted in a known manner and subjected to an annealing treatment at a relatively low temperature to form the desired hard magnetic phase. A previous sintering or melting process with subsequent comminution of the material is therefore not necessary. Nevertheless, extremely fine powders can be obtained with the grinding process.
Vorteilhafte Ausgestaltungen des erfindungsgemäßen Verfahrens gehen aus den Unteransprüchen hervor.Advantageous refinements of the method according to the invention emerge from the subclaims.
Die Erfindung wird nachfolgend noch weiter anhand der Herstellung einer besonderen hartmagnetischen Metall-Metall-Bor (M₁M₂B)-Legierung erläutert.The invention is explained below with reference to the production of a special hard magnetic metal-metal-boron (M₁M₂B) alloy.
Bei diesem Legierungstyp ist M₂ aus der dem Periodensystem der Elemente entnehmbaren Gruppe der späten Übergangsmetalle gewählt. Bei M₁ handelt es sich um ein Seltenes Erdmetall oder ein Actinid. Die entsprechenden metallischen Ausgangskomponenten sollen pulverförmig sein oder zumindest pulverähnliches Aussehen haben, wobei sie vorzugsweise in elementarer Form oder gegebenenfalls auch in Form von Legierungen oder Verbindungen vorliegen können. Bei M₁ und M₂ kann es sich insbesondere um die Metalle Neodym (Nd) und Eisen (Fe) handeln. Dementsprechend sei nachfolgend als Ausführungsbeispiel die ternäre Legierung NdFeB angenommen.In this type of alloy, M₂ is selected from the group of late transition metals that can be found in the periodic table of the elements. M₁ is a rare earth metal or an actinide. The corresponding metallic starting components should be in powder form or at least have a powder-like appearance, whereby they can preferably be in elemental form or, if appropriate, also in the form of alloys or compounds. M₁ and M₂ can in particular be the metals neodymium (Nd) and iron (Fe). Accordingly, the ternary alloy NdFeB is assumed below as an exemplary embodiment.
Zur Herstellung von Pulver aus dieser Legierung werden zunächst Pulver der beiden metallischen Ausgangskomponenten Fe und Nd sowie B-Pulver zusammen mit gehärteten Stahlkugeln in einen geeigneten Mahlbecher gegeben, wobei das Mengenverhältnis der drei Pulversorten dieses Pulvergemisches durch die vorbestimmte resultierende atomare Konzentration des aus diesen Pulvern herzustellenden Materials bestimmt ist. So kann beispielsweise das Mengenverhältnis der drei elementaren Pulversorten dieses Pulvergemisches so gewählt werden, daß nach einer durchzuführenden Diffusionsreaktion die Zusammensetzung Nd₁₅Fe₇₇B₈ entstanden ist. Allgemein kann der Anteil des Nd zwischen 10 und 20 Atom-% und der des B zwischen 2 und 10 Atom-% betragen, wobei der Fe-Anteil den Rest ausmacht.To produce powders from this alloy, powders of the two metallic starting components Fe and Nd and B powder together with hardened steel balls are first placed in a suitable grinding bowl, the ratio of the three powder types of this powder mixture being determined by the predetermined resulting atomic concentration of the powder to be produced from these powders Material is determined. For example, the quantitative ratio of the three elementary types of powder of this powder mixture can be chosen so that the composition Nd₁₅Fe₇₇B₈ is formed after a diffusion reaction to be carried out. In general, the proportion of Nd can be between 10 and 20 atomic% and that of B between 2 and 10 atomic%, with the Fe fraction making up the rest.
Die Größe der einzelnen Pulver kann zwar beliebig sein; jedoch ist eine ähnliche Größenverteilung der beiden beteiligten metallischen Ausgangskomponenten in einem Bereich zwischen 5 µm und 1 mm, insbesondere zwischen 20 µm und 0,5 mm vorteilhaft. Gemäß dem gewählten Ausführungsbeispiel werden Fe-Pulver mit einer Größe der Pulverpartikel unter 40 µm und Nd-Feilspäne mit einer Partikelgröße unter 0,5 mm verwendet. Außerdem sollte das B-Pulver möglichst fein sein, wobei vorteilhaft deren Partikel unter 10 µm, vorzugsweise unter 1 µm ausgedehnt sind. Dabei kann es sich insbesondere um weitgehend amorphes B-Pulver handeln. Diese drei Pulver mit entsprechenden Partikelgrößen werden dann erfindungsgemäß einem Mahlprozeß unterzogen, wie er bei Verfahren des mechanischen Legierens allgemein bekannt ist (vgl. z.B. "Metallurgical Transactions", Vol. 5, August 1974, Seiten 1929 bis 1934, oder "Scientific American", Vol. 234, 1976, Seiten 40 bis 48). Dementsprechend werden also die drei pulverförmigen Ausgangskomponenten in eine Planetenkugelmühle (Marke Fritsch: Typ "Pulverisette 5") gegeben, deren beispielsweise 100 Stahlkugel Durchmesser von jeweils 10 mm aufweisen. Die Dauer des Mahlprozesses hängt sowohl von der gewünschten Feinheit des Mischpulvers als auch von den Mahlparametern ab. Wichtige Parameter beim Mahlen sind der Kugeldurchmesser, die Kugelanzahl sowie das Mahltiegel- und Kugelmaterial. Auch die Mahlgeschwindigkeit und das Verhältnis der Stahlkugeln zur Pulvermenge sind weitere Parameter, welche die notwendige Mahldauer bestimmen. Um eine Oberflächenoxidation der Partikel zu verhindern, wird der aus Stahl bestehende Mahlbehälter der Mühle unter Schutzgas wie beispielsweise Argon oder Helium gehalten und erst nach Beendigung des Mahlprozesses wieder geöffnet.The size of the individual powders can be arbitrary; however, a similar size distribution of the two metallic starting components involved in a range between 5 μm and 1 mm, in particular between 20 μm and 0.5 mm, is advantageous. According to the selected embodiment, Fe powders with a size of the powder particles below 40 µm and Nd filings with a size of less than 0.5 mm are used. In addition, the B powder should be as fine as possible, the particles advantageously being less than 10 μm, preferably less than 1 μm. In particular, this can be largely amorphous B powder. These three powders with corresponding particle sizes are then subjected, according to the invention, to a grinding process as is generally known in mechanical alloying processes (cf., for example, "Metallurgical Transactions", Vol. 5, August 1974, pages 1929 to 1934, or "Scientific American", Vol. 234, 1976, pages 40 to 48). Accordingly, the three powdered starting components are placed in a planetary ball mill (brand Fritsch: type "Pulverisette 5"), the 100 steel balls of which, for example, each have a diameter of 10 mm. The duration of the grinding process depends on the desired fineness of the mixed powder as well as on the grinding parameters. Important parameters for grinding are the ball diameter, the number of balls and the grinding crucible and ball material. The grinding speed and the ratio of the steel balls to the amount of powder are further parameters that determine the necessary grinding time. To prevent surface oxidation of the particles, the mill's steel grinding bowl is kept under protective gas such as argon or helium and only opened again after the grinding process has ended.
Während des Mahlprozesses bilden sich bereits nach etwa 2 Stunden Mahlzeit feingeschichtete Pulverkörner, die aus Fe- und Nd-Schichten bestehen. Dabei werden die B-Teilchen sowohl an den Fe/Nd-Grenzflächen als auch in den elementaren Metallen eingelagert oder an diesen angelagert. Mit fortschreitender Mahldauer wird diese Schichtstruktur immer feiner, bis sie nach etwa 10 bis 30 Stunden Mahlzeit nicht mehr lichtmikroskopisch auflösbar ist. Es sind dann also Pulverpartikel eines Mischpulvers entstanden, die aus einer innigen Vermengung von Fe und Nd mit ein- oder angelagerten B-Teilchen, deren Größe deutlich kleiner als 1 µm ist, bestehen. Die Pulverpartikel selbst haben dabei einen Durchmesser von etwa 1 bis 200 µm. Bei Röntgen-Untersuchungen dieses Mischpulvers sind lediglich stark verbreiterte Intensitätsmaxima von Fe zu erkennen. Hinweise auf eine Bildung von amorphem FeNd oder einer FeNd-Phase bestehen nicht.During the milling process, finely layered powder grains, which consist of Fe and Nd layers, form after only about 2 hours of meal. The B-particles are embedded or attached to the Fe / Nd interfaces as well as in the elemental metals. As the grinding time progresses, this layer structure becomes ever finer until it can no longer be resolved by light microscopy after about 10 to 30 hours of eating. This then gave rise to powder particles of a mixed powder which consist of an intimate mixture of Fe and Nd with embedded or attached B-particles, the size of which is significantly smaller than 1 µm. The powder particles themselves have a diameter of approximately 1 to 200 µm. In X-ray examinations of this mixed powder, only strongly broadened intensity maxima of Fe can be seen. There is no evidence of the formation of amorphous FeNd or an FeNd phase.
Die sich anschließende Reaktionsglühung muß ebenfalls unter Schutzgas oder unter Vakuum erfolgen. Dabei kann die Glühung bei einer oder mehreren verschiedenen Temperaturen vorgenommen werden. Auch eine kontinuierliche Temperaturänderung ist möglich. Bei einer Glühbehandlung von beispielsweise 1 Stunde bei 600°C bildet sich durch eine Diffusionsreaktion die gewünschte Nd₂Fe₁₄B-Phase, die über hervorragende hartmagnetische Eigenschaften verfügt. So zeigt das reagierte Pulver nach Einbetten in Kunststoff eine Koerzitivkraft von über 10 kOe.The subsequent reaction annealing must also take place under protective gas or under vacuum. The annealing can be carried out at one or more different temperatures. A continuous change in temperature is also possible. In the case of an annealing treatment of, for example, 1 hour at 600 ° C., the desired Nd₂Fe₁ bildetB phase is formed by a diffusion reaction and has excellent hard magnetic properties. The reacted powder shows a coercive force of over 10 kOe after embedding in plastic.
Der eigentliche Vorteil des erfindungsgemäßen Verfahrens besteht darin, daß mit dem Mahlprozeß nach Art des mechanischen Legierens eine äußerst innige Durch mischung der beteiligten Elemente besteht. Somit werden bei der anschließenden Diffusionsreaktion nur sehr kurze Diffusionswege benötigt, die bei verhältnismäßig niedrigen Temperaturen bzw. kurzen Zeiten überwunden werden können. Dadurch ist es möglich, eine äußerst feine Mikrostruktur der Nd₂Fe₁₄B-Phase zu erzielen, die z.B. der von schnell-abgeschrecktem Material entspricht. Die magnetische Härtung dieses Materials erfolgt dementsprechend durch Blochwand-Verankerung. Ein besonderer Vorteil ist dabei, daß die Glühung bei Temperaturen unterhalb von 640°C, der niedrigsten eutektischen Temperatur im binären FeNd-Phasendiagramm, erfolgen kann. Oberhalb dieser Temperatur würde nämlich wegen des Vorhandenseins einer flüssigen Phase eine schnelle Kornvergrößerung eintreten. Für das genannte ternäre hartmagnetische Material erscheint eine Reaktionstemperatur zwischen etwa 400 °C und 640°C am geeignetsten.The real advantage of the method according to the invention is that an extremely intimate through with the grinding process in the manner of mechanical alloying mix of the elements involved. In the subsequent diffusion reaction, therefore, only very short diffusion paths are required, which can be overcome at relatively low temperatures or short times. This makes it possible to achieve an extremely fine microstructure of the Nd₂Fe₁₄B phase, which corresponds, for example, to that of rapidly quenched material. The magnetic hardening of this material is carried out accordingly by Blochwand anchoring. A particular advantage is that the annealing can take place at temperatures below 640 ° C, the lowest eutectic temperature in the binary FeNd phase diagram. Above this temperature, a rapid grain enlargement would occur due to the presence of a liquid phase. For the ternary hard magnetic material mentioned, a reaction temperature between approximately 400 ° C. and 640 ° C. appears most suitable.
Gegebenenfalls führt eine Glühung bei höheren Temperaturen wie z.B. bei 900°C während einer Stunde ebenfalls zu guten Werten der Koerzitivkraft. Das dabei gebildete Pulver ist jedoch verhältnismäßig grobkörnig, weist Fremdphasen an den Korngrenzen auf und zeigt einen von der behinderten Domänenkeimbildung geprägten magnetischen Härtungsmechanismus. Es ähnelt somit dem Material, das entsprechend der genannten EP-A1 hergestellt ist, und läßt sich dann in bekannter Weise zu einem anisotropen Magneten weiterverarbeiten. Die aus der EP-A1 bekannten Temperaturbehandlungen lassen sich auch hierfür vorteilhaft einsetzen.If necessary, annealing at higher temperatures, e.g. at 900 ° C for one hour also at good values for the coercive force. However, the powder formed is relatively coarse-grained, has foreign phases at the grain boundaries and shows a magnetic hardening mechanism characterized by the blocked domain nucleation. It thus resembles the material which is produced in accordance with the aforementioned EP-A1 and can then be further processed in a known manner to form an anisotropic magnet. The temperature treatments known from EP-A1 can also be used advantageously for this.
Die Kompaktierung und Einstellung der magnetischen Anisotropie der erfindungsgemäß bei verhältnismäßig tiefen Temperaturen gebildeten NdFeB-Partikel, deren Gefüge dem von schnell-abgeschrecktem NdFeB entspricht, kann mit den für diese Materialien entwickelten Verfahren in bekannter Weise erfolgen.The compaction and adjustment of the magnetic anisotropy according to the invention in proportion NdFeB particles formed at low temperatures, the structure of which corresponds to that of rapidly quenched NdFeB, can be carried out in a known manner using the processes developed for these materials.
Aber auch ohne Kompaktierung kann dieses Pulver z.B. als kunststoffgebundener isotroper Magnet Verwendung finden.But even without compacting, this powder can e.g. can be used as a plastic-bonded isotropic magnet.
Die Zusammensetzung des dem Ausführungsbeispiel zugrundegelegten Materials kann bei der Einwaage von der stöchiometrischen Zusammensetzung Nd₂Fe₁₄B abweichen, etwa in der Weise, wie es für die aus den genannten Veröffentlichungen bekannten Verfahren üblich ist. Darüber hinaus kann eines oder mehrere der drei beteiligten Elemente durch andere Elemente partiell oder gegebenenfalls sogar vollständig substituiert werden. So kann etwa Nd insbesondere durch ein Element der schweren Seltenen Erden, wie etwa Dy oder Tb, partiell oder z.B. durch Pr vollständig ersetzt werden. Statt Fe kann ein anderes Element der späten Übergangsmetalle, z.B. Co oder Ni,vorgesehen werden. Auch eine partielle Ersetzung durch Al ist möglich. Schließlich kann B durch ein anderes Metalloid partiell substituiert werden. Die verwendeten Ausgangspulver richten sich dabei nach den gewünschten Zusammensetzungen. Hinsichtlich des Diffusionsprozesses ist aus thermodynamischen Gründen besonders vorteilhaft, wenn elementare Pulver verwendet werden, da hier die treibende Kraft für die Diffusionsreaktion am größten ist. Aus dem gleichen Grund ist auch die Verwendung von amorphem B-Pulver besonders vorteilhaft. Daneben können die beteiligten Elemente auch in Form von vorlegiertem Pulver, z.B. als Fe₂B oder als eine NdFe-Phase oder eine NdFe-Legierung mit 20 bis 40 Atom-% Fe zugegeben werden. Bei der Auswahl von Vorlegierungen sind metastabile Phasen wiederum aus den genannten thermodynamischen Gründen den Gleichgewichtsphasen vorzuziehen.The composition of the material on which the exemplary embodiment is based can deviate from the stoichiometric composition Nd₂Fe₁₄B during the weighing in, approximately in the manner which is customary for the processes known from the publications mentioned. In addition, one or more of the three elements involved can be partially or optionally even completely substituted by other elements. For example, Nd can be partially or completely replaced by an element of the heavy rare earths, such as Dy or Tb, for example. Instead of Fe, another element of the late transition metals, for example Co or Ni, can be provided. A partial replacement by Al is also possible. Finally, B can be partially substituted by another metalloid. The starting powders used depend on the desired compositions. With regard to the diffusion process, it is particularly advantageous for thermodynamic reasons if elemental powders are used, since the driving force for the diffusion reaction is greatest here. For the same reason, the use of amorphous B powder is particularly advantageous. In addition, the elements involved can also be in the form of pre-alloyed powder, for example as Fe₂B or as an NdFe phase or an NdFe alloy with 20 to 40 atomic% Fe can be added. When selecting master alloys, metastable phases are again preferred to the equilibrium phases for the thermodynamic reasons mentioned.
Gemäß dem gewählten Ausführungsbeispiel wurde angenommen, daß mindestens zwei metallische Ausgangskomponenten M₁ und M₂ in Pulverform vorgesehen werden, wobei jede dieser beiden Komponenten aus einem metallischen (chemischen) Element oder aus einer Legierung oder Verbindung mit diesem Element besteht. Gegebenenfalls ist es jedoch auch möglich, von nur einer einzigen pulverförmigen Legierung der beiden Ausgangsmetalle M₁ und M₂ auszugehen; d.h., die Legierung M₁- M₂ allein liefert dann die beiden metallischen Komponenten des herzustellenden Dauermagnetwerkstoffes. Im Falle von Nd₂Fe₁₄B wäre dies die Legierung Nd₁₆Fe₈₄ in Pulverform, die zusammen mit dem B-Pulver das zu mahlende Pulvergemisch bildet.According to the selected embodiment, it was assumed that at least two metallic starting components M 1 and M 2 are provided in powder form, each of these two components consisting of a metallic (chemical) element or of an alloy or compound with this element. If necessary, it is also possible to start from only a single powdery alloy of the two starting metals M₁ and M₂; i.e., the alloy M₁-M₂ alone then provides the two metallic components of the permanent magnet material to be produced. In the case of Nd₂Fe₁₄B this would be the alloy Nd₁₆Fe₈₄ in powder form, which together with the B powder forms the powder mixture to be ground.
Claims (12)
Applications Claiming Priority (2)
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DE3610475 | 1986-03-27 | ||
DE3610475 | 1986-03-27 |
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EP0243641A1 true EP0243641A1 (en) | 1987-11-04 |
EP0243641B1 EP0243641B1 (en) | 1990-07-25 |
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EP87103787A Expired - Lifetime EP0243641B1 (en) | 1986-03-27 | 1987-03-16 | Process for manufacturing a permanent-magnet material from powder |
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US (1) | US4844751A (en) |
EP (1) | EP0243641B1 (en) |
JP (1) | JPH0645841B2 (en) |
DE (1) | DE3763888D1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3709138A1 (en) * | 1987-03-20 | 1988-09-29 | Siemens Ag | Process for producing a magnetic material from pulverulent starting components |
EP0360120A1 (en) * | 1988-09-23 | 1990-03-28 | Siemens Aktiengesellschaft | Preparation process of a material including a hard magnetic phase from powder components |
EP0449890A1 (en) * | 1988-12-22 | 1991-10-09 | Univ Western Australia | Process for the production of metals, alloys and ceramic materials. |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US5004499A (en) * | 1987-11-02 | 1991-04-02 | Union Oil Company Of California | Rare earth-iron-boron compositions for polymer-bonded magnets |
JPH0439915A (en) * | 1990-06-05 | 1992-02-10 | Seiko Instr Inc | Manufacture of rare-earth magnet |
JP3129593B2 (en) * | 1994-01-12 | 2001-01-31 | 川崎定徳株式会社 | Manufacturing method of rare earth, iron and boron sintered magnets or bonded magnets |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3785801A (en) * | 1968-03-01 | 1974-01-15 | Int Nickel Co | Consolidated composite materials by powder metallurgy |
FR2207194A1 (en) * | 1972-11-17 | 1974-06-14 | Int Nickel Ltd | |
EP0200079A1 (en) * | 1985-04-26 | 1986-11-05 | Siemens Aktiengesellschaft | Method of manufacturing a metallic article from an amorphous alloy |
EP0126802B1 (en) * | 1983-05-25 | 1988-12-14 | Sumitomo Special Metals Co., Ltd. | Process for producing of a permanent magnet |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5037631A (en) * | 1973-08-06 | 1975-04-08 | ||
DE3479940D1 (en) * | 1983-10-26 | 1989-11-02 | Gen Motors Corp | High energy product rare earth-transition metal magnet alloys containing boron |
JPS60138056A (en) * | 1983-12-27 | 1985-07-22 | Sumitomo Special Metals Co Ltd | Material for sintered magnet |
US4541877A (en) * | 1984-09-25 | 1985-09-17 | North Carolina State University | Method of producing high performance permanent magnets |
DE3761255D1 (en) * | 1986-02-05 | 1990-02-01 | Siemens Ag | METHOD FOR PRODUCING A POWDER-SHAPED AMORPHOUS MATERIAL BY CARRYING OUT A GRINDING PROCESS. |
-
1987
- 1987-03-16 DE DE8787103787T patent/DE3763888D1/en not_active Expired - Fee Related
- 1987-03-16 EP EP87103787A patent/EP0243641B1/en not_active Expired - Lifetime
- 1987-03-23 US US07/028,240 patent/US4844751A/en not_active Expired - Lifetime
- 1987-03-24 JP JP62071322A patent/JPH0645841B2/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3785801A (en) * | 1968-03-01 | 1974-01-15 | Int Nickel Co | Consolidated composite materials by powder metallurgy |
FR2207194A1 (en) * | 1972-11-17 | 1974-06-14 | Int Nickel Ltd | |
EP0126802B1 (en) * | 1983-05-25 | 1988-12-14 | Sumitomo Special Metals Co., Ltd. | Process for producing of a permanent magnet |
EP0200079A1 (en) * | 1985-04-26 | 1986-11-05 | Siemens Aktiengesellschaft | Method of manufacturing a metallic article from an amorphous alloy |
Non-Patent Citations (2)
Title |
---|
CHEMICAL ABSTRACTS, Band 103, Nr. 18, 4. November 1985, Seite 719, Zusammenfassung Nr. 152451f, Columbus, Ohio, US; & JP-A-60 091 601 (SUMITOMO SPECIAL METALS CO., LTD.) 23.05.1985 * |
CHEMICAL ABSTRACTS, Band 83, Nr. 4, 28. Juli 1975, Seite 235, Zusammenfassung Nr. 31785c, Columbus, Ohio, US; K.P. TSOMAYA: "Electron microscopic and electron diffraction studies of dispersed boron powders" & POROSHK. METALL. 1975, (3), 87-92 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3709138A1 (en) * | 1987-03-20 | 1988-09-29 | Siemens Ag | Process for producing a magnetic material from pulverulent starting components |
EP0360120A1 (en) * | 1988-09-23 | 1990-03-28 | Siemens Aktiengesellschaft | Preparation process of a material including a hard magnetic phase from powder components |
DE3832472A1 (en) * | 1988-09-23 | 1990-03-29 | Siemens Ag | METHOD FOR PRODUCING A MATERIAL WITH A HARD MAGNETIC PHASE FROM POWDER-BASED STARTING COMPONENTS |
EP0449890A1 (en) * | 1988-12-22 | 1991-10-09 | Univ Western Australia | Process for the production of metals, alloys and ceramic materials. |
EP0449890A4 (en) * | 1988-12-22 | 1993-06-23 | The University Of Western Australia | Process for the production of metals, alloys and ceramic materials |
Also Published As
Publication number | Publication date |
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JPH0645841B2 (en) | 1994-06-15 |
JPS62240742A (en) | 1987-10-21 |
EP0243641B1 (en) | 1990-07-25 |
DE3763888D1 (en) | 1990-08-30 |
US4844751A (en) | 1989-07-04 |
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