EP0448482B1 - Herstellungsverfahren eines ausgerichteten und strukturierten Körpers - Google Patents

Herstellungsverfahren eines ausgerichteten und strukturierten Körpers Download PDF

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Publication number
EP0448482B1
EP0448482B1 EP91420091A EP91420091A EP0448482B1 EP 0448482 B1 EP0448482 B1 EP 0448482B1 EP 91420091 A EP91420091 A EP 91420091A EP 91420091 A EP91420091 A EP 91420091A EP 0448482 B1 EP0448482 B1 EP 0448482B1
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EP
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Prior art keywords
compound
magnetic
temperature
crystallites
particles
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EP91420091A
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English (en)
French (fr)
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EP0448482A1 (de
Inventor
Robert Tournier
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Centre National de la Recherche Scientifique CNRS
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Centre National de la Recherche Scientifique CNRS
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/02—Use of electric or magnetic effects
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S505/00—Superconductor technology: apparatus, material, process
    • Y10S505/725—Process of making or treating high tc, above 30 k, superconducting shaped material, article, or device
    • Y10S505/729—Growing single crystal, e.g. epitaxy, bulk

Definitions

  • the present invention relates to a method for preparing an oriented and textured magnetic body.
  • the document GB-A-977 596 describes a process for the preparation of ferromagnetic compounds using levitation, the action of a high frequency induction field and rapid quenching.
  • the present invention provides a process for preparing oriented and textured magnetic bodies using, in combination:
  • a sedimentation effect caused by a magnetic force so that, during their formation, the germs or crystallites of the desired body gather in the same area of a container, generally at the bottom, from which it results in particular a purification action since the various parasitic particles likely to exist in the melt or in the dispersion and which have a magnetic susceptibility different from that of the desired body are not used with the same efficiency as the desired body; and a texturing effect linked to the creation of a temperature gradient in the region where sedimentation occurs, so as to promote agglomeration or solidification according to the growth axes of the body sought to obtain it in monocrystalline or crystallite form oriented.
  • magnetic bodies have a magnetic susceptibility ⁇ which is generally anisotropic.
  • axis c there are substances which have an axis of easy magnetization
  • ⁇ the magnetic susceptibility
  • B a magnetic field
  • the particles tend to orient along their axis of easy magnetization and there is an energy gain ⁇ E compared to the case of a substance with random distribution of the magnetization axes.
  • ⁇ E V ⁇ B2 ⁇ ⁇ / 2 ⁇ 0
  • this energy gain ⁇ E must be significantly higher than the energy linked to thermal agitation, namely kT where T is the absolute temperature and k the constant by Boltzmann.
  • a compound of the Nd2Fe14B type will undergo at 1500 K a force of 30 times the thinker and, at the solidification temperature of the eutectic, close to 1000 K, a force of 50 times the gravity.
  • the crystallites of step a) come from monocrystalline particles of the desired magnetic body mixed with a second body whose melting temperature and magnetic susceptibility are lower than that of the desired body, all being brought to a temperature higher than the melting temperature of the second body and lower, but close, to the melting temperature of the desired magnetic body.
  • step a) is carried out starting from the desired magnetic body in massive form, and by bringing this material to the liquid state without overheating so that there remain numerous germs of small sizes. of the desired body.
  • step a) consists of starting the desired magnetic body in solid form, then heating it to a temperature above its melting point and cooling slowly until the first germs of the body appear.
  • step a) comprises the steps consisting in starting from a mixture of bodies comprising solid particles constituting the desired magnetic body but which have not yet reacted, these particles being in suspension in a non-reactive liquid, the assembly being brought to a temperature below the melting temperature of said constituent particles.
  • FIG. 1 very schematically illustrates a device for implementing the method according to the invention.
  • This device comprises a coil 1.
  • a system of Cartesian coordinate axes (x, y, z) has its origin in the center of the coil, equidistant from its two ends.
  • This coil is placed so that its axis, which corresponds to the z axis of the coordinate system, is oriented according to the gravity field, orientation which will be described as vertical below.
  • a crucible 2 is placed in the coil 1 so that its axis substantially coincides with the axis of the coil.
  • the crucible 2 can be moved vertically and is made of a non-magnetic material.
  • An oven (not shown) is located inside the coil and surrounds the crucible.
  • FIG. 2 represents the intensity B of the induction on the z axis as a function of the height z when a current flows in the coil 1.
  • a magnetic induction B and on the other hand a magnetic induction gradient dB / dz.
  • the weight In the chosen axis system, the weight is negative.
  • the magnetic force ( ⁇ / ⁇ 0) ⁇ B ⁇ dB / dz is added to the weight when it is negative, that is to say for the values of z greater than zero.
  • the internal diameter of the winding is chosen here slightly greater than one tenth of a meter (0.15 m).
  • NdFeB which is a material used for the formation of permanent magnets.
  • This material combines both a very high coercivity and a very high magnetic energy.
  • Nd2Fe14B crystallites of small dimensions in order to increase the coercivity, the axis c of which is oriented so as to produce the highest remanent induction possible.
  • the assembly is first raised to a temperature of 300 to 1110 ° C.
  • the Nd3Fe eutectic is liquid from 700 ° C while the Nd2Fe14B is not completely dissolved in the eutectic at 1100 ° C.
  • This step preferably takes place under an inert atmosphere.
  • a field is applied to orient the crystallines of Nd2Fe14B then the crucible is moved towards the zone corresponding to the abscissa z m for sediment the crystallites of Nd2Fe14B which remain oriented and assemble at the bottom of the crucible to form grains of Nd2FE14B with Nd3Fe at the grain boundaries.
  • Nd3Fe The majority of Nd3Fe is found on the surface of the crucible. Cooling is then carried out which can be relatively rapid, for example lasting an hour and a half as indicated in FIG. 3A. Once this solid obtained, one can by sawing separate the lower part (Nd2Fe14B) from the upper part (Nd3Fe and impurities).
  • NdFeB alloy of typical composition (in% atoms) 77 Fe, 15.3 Nd, 7.7 B, so that the compound Nd2Fe14B is in presence of an excess of Nd3Fe eutectic (approximately 10%).
  • the composition, contained in the crucible 2 is brought to a temperature of 1170 to 1185 ° C., that is to say a temperature higher than the melting temperature of Nd2Fe14B, but without overheating, from which it follows that there remain germs made up of Nd2Fe14B crystallites.
  • the furnace containing the crucible used is constructed so that the cooling is established from the periphery towards the core.
  • the desired body is thus obtained with an oriented structure with a vertical axis c. It will further be noted that this process has the advantage of leaving possible impurities on the surface of the composition during cooling (this would also be the case for the other variants of the process described here).
  • the thermal cycle is illustrated in Figure 3C.
  • the whole is heated above the melting temperature, so as to overheat and eliminate germs.
  • Slow cooling is then carried out to 1050 ° C. under a magnetic force, for example at a rate of 20 ° C. per hour to solidify directionally the sedimented material at the bottom of the crucible.
  • a horizontal temperature gradient is imposed from the periphery to the center of the crucible to solidify directionally the material gradually from the periphery to the core.
  • the application of the magnetic force HdH / dz had the effect of placing any residues of iron ⁇ on the surface of the liquid. After solidification, traces of ⁇ iron are found on the surface of the solidified ingot, the Nd2Fe14B crystallites being oriented along the vertical c axis.
  • the mixture is brought to a temperature of 920 ° C for one hour under a field of about 1 tesla, for example, to obtain oriented crystallites whose size is of the order of a micrometer and having a strong coercive field. Cooling in the oven under HdH / dz of the order of 10 T2 / m makes it possible to sediment Nd2Fe14B and to have excess eutectic at the surface from which it can then be eliminated. An element is thus obtained consisting of oriented particles of sizes close to a micrometer and with a strong coercive field.
  • This product can be manufactured using variant 2 of the process according to the invention.
  • the magnetic force makes it possible to sediment the desired body as it appears during cooling and facilitates the sintering of the Sm2T17 phase with an oriented structure.
  • the excess SmT5 phase is expelled during sintering and remains concentrated above Sm2T17 because its susceptibility is lower than that of Sm2T17.
  • Samarium oxides will float on the surface because their susceptibility is much lower than that of other elements.
  • the materials must be textured so that the currents flow in the ab planes of the crystallographic structure rather than in the direction of the c axis.
  • ⁇ T is horizontal and the field vertical.
  • the mixture is placed in a crucible and heated to 1050 ° C for half an hour in a homogeneous field of several teslas.
  • the starting compound is not completely melted, only the silver oxide being in fusion.
  • the crucible is then moved to the position of maximum magnetic force to achieve sedimentation of the desired body.
  • Slow cooling is then carried out, for example of the order of ° C. per hour to a temperature (950 ° C.) lower than the solidification temperature of the silver, after which it is possible to cool more quickly.
  • a homogenization annealing is carried out at 1050 ° C. under a field of a few teslas to homogenize and orient. It is cooled slowly, of the order of 1 ° C per hour to 1020 ° C (not shown), then the crucible is moved to the position of maximum magnetic force and it is gradually lowered from 1020 ° C to 980 ° . Then we go to faster cooling.
  • a textured solid is obtained as soon as the temperature gradients are properly oriented relative to the direction of easy magnetization.
  • an intimate mixture of powders with composition 8 BaCuO2 + 4 Cu0 + R2O3 is heated to 1050 ° C. with an HdH / dz value of the order of 200 T2 / m. Then cooled at a rate of 1 ° C per hour to 980 ° and quickly to room temperature.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Hard Magnetic Materials (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Thin Magnetic Films (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)

Claims (7)

  1. Verfahren zum Präparieren bzw. Herstellen einer orientierten und texturierten magnetischen Zusammensetzung bzw. Verbindung, dadurch gekennzeichnet, daß es die folgenden Schritte aufweist:
    a) Präparieren einer Zusammensetzung bei einer Temperatur, so daß sie Kristallite der Zusammensetzung aufweist, und zwar in der Anwesenheit einer Flüssigkeit,
    b) Aussetzen der Zusammensetzung einer magnetischen Kraft, die eine Sedimentation der Kristallite erzeugt,
    c) Abkühlen der Zusammensetzung in der Anwesenheit der magnetischen Kraft, während man einen geeigneten Temperaturgradienten anlegt, um die Entwicklung einer gewünschten bzw. erforderlichen Textur in dem Sedimentationsgebiet zu verbessern.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Magnetkraft aus der Anwesenheit eines magnetischen Feldes mit einem hohen Gradienten in der Schwerkraftsrichtung resultiert.
  3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß es ferner zwischen den Schritten a) und b) folgenden Schritt aufweist: Anlegen eines magnetischen Felds mit einem praktischen Nullgradienten.
  4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Kristallite des Schrittes a) aus Einkristallpartikeln bzw. -teilchen der gewünschten bzw. erforderlichen magnetischen Zusammensetzung gemischt mit einem zweiten Material, dessen Schmelztemperatur und magnetischem Susceptibilität kleiner als diejenigen der gewünschten Zusammensetzung sind, wobei die Mischung auf eine Temperatur erwärmt wird, die höher als die Schmelztemperatur des zweiten Materials und niedriger als, aber dichter bei, der Schmelztemperatur der gewünschten magnetischen Zusammensetzung ist, bestehen.
  5. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Schritt a) folgendes aufweist: Ausgehen bzw. Starten von der gewünschten magnetischen Zusammensetzung in einer Bulkform bzw. in einer massiven Form und Erwärmen der Zusammensetzung bis zu dem Flüssigzustand, und zwar ohne zu überhitzen, so daß zahlreiche Keime der gewünschten Zusammensetzung von kleiner Größe verbleiben.
  6. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Schritt a) folgendes aufweist: Ausgehen bzw. Starten von der gewünschten magnetischen Zusammensetzung in dem Festzustand und dann erwärmen der Zusammensetzung auf eine Temperatur höher als ihr Schmelzpunkt und ihr gestatten langsam abzukühlen, bis erste Keime der Zusammensetzung erscheinen.
  7. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Schritt a) folgende Schritte aufweist: Ausgehen bzw. Starten von einer Mischung aus Materialien, die solide bzw. feste Partikel aufweisen, die die gewünschte magnetische Zusammensetzung aufbauen, die aber noch nicht reagiert haben, wobei die Teilchen in Suspension in einer nicht reaktiven Flüssigkeit sind, wobei die Mischung auf eine Temperatur niedriger als die Schmelztemperatur der aufbauenden bzw. konstitutiven Teilchen ist.
EP91420091A 1990-03-22 1991-03-19 Herstellungsverfahren eines ausgerichteten und strukturierten Körpers Expired - Lifetime EP0448482B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9003922 1990-03-22
FR909003922A FR2660107B1 (fr) 1990-03-22 1990-03-22 Procede de preparation d'un corps magnetique oriente et texture.

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EP0448482A1 EP0448482A1 (de) 1991-09-25
EP0448482B1 true EP0448482B1 (de) 1995-11-02

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US (1) US5168096A (de)
EP (1) EP0448482B1 (de)
JP (1) JP2986942B2 (de)
CA (1) CA2038639A1 (de)
DE (1) DE69114160T2 (de)
FR (1) FR2660107B1 (de)

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Publication number Priority date Publication date Assignee Title
US5529981A (en) * 1992-03-05 1996-06-25 Holloway; Alex Process and apparatus for preparing biaxially textured materials using anisotropy in the paramagnetic susceptibility
US5308800A (en) * 1992-03-23 1994-05-03 The United States Of America As Represented By The Secretary Of The Navy Apparatus and method for forming textured bulk high temperature superconducting materials
US5444425A (en) * 1994-02-28 1995-08-22 The Regents Of The University Of Colorado Flux-trapped superconducting magnets and method of manufacture
DE4418750C2 (de) * 1994-05-28 2000-06-15 Vaw Ver Aluminium Werke Ag Verfahren zur Herstellung von verschleißfesten Oberflächen auf Formgußteilen
FR2748344B1 (fr) * 1996-05-06 1998-10-16 Ugimag Sa Procede d'obtention de materiau magnetiquement anisotrope a base de terres rares et metaux de transition par solidification d'un alliage liquide sous champ orienteur
US6596076B1 (en) * 1998-06-30 2003-07-22 Director-General Of Agency Of Industrial Science And Technology Apparatus and method for altering the apparent effects of gravity
DE19908597A1 (de) * 1999-02-27 2000-09-14 Aventis Res & Tech Gmbh & Co Verfahren zum Vergüten eines Supraleitermaterials mit hoher Remanenzinduktion, vergütetes Supraleitermaterial und dessen Verwendung
DE10349980A1 (de) * 2003-10-24 2005-09-22 Hunck, Wolfgang, Dipl.-Ing. Abkühlen stromdurchfluteter Schmelzen
US7850520B2 (en) * 2005-04-26 2010-12-14 Konami Australia Pty. Ltd. Gaming machine with multiple reel matrix
US9255343B2 (en) * 2013-03-08 2016-02-09 Ut-Battelle, Llc Iron-based composition for magnetocaloric effect (MCE) applications and method of making a single crystal
CN113355734A (zh) * 2021-06-07 2021-09-07 上海工程技术大学 磁场诱导等温凝固过程中易轴织构的制备方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991005880A1 (fr) * 1989-10-13 1991-05-02 Centre National De La Recherche Scientifique Procede de preparation de materiaux magnetiques de tres haute qualite

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CA657098A (en) * 1963-02-05 L. Stuijts Andreas Method of manufacturing monocrystalline bodies
US3102002A (en) * 1960-03-25 1963-08-27 Univ Pittsburgh Ferromagnetic materials prepared from lanthanons and transition metals
US3279602A (en) * 1963-02-18 1966-10-18 Al Inc Magnetic separation process and equipment therefor
US3672872A (en) * 1970-06-01 1972-06-27 Anvar Method of separation of a substance in a solid or liquid phase from a matrix in the liquid phase
JPS5236492B2 (de) * 1972-12-20 1977-09-16
JPS57184572A (en) * 1981-05-11 1982-11-13 Hitachi Ltd Production of unidirectionally solidified casting
US4539040A (en) * 1982-09-20 1985-09-03 Mawardi Osman K Beneficiating ore by magnetic fractional filtration of solutes

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991005880A1 (fr) * 1989-10-13 1991-05-02 Centre National De La Recherche Scientifique Procede de preparation de materiaux magnetiques de tres haute qualite

Also Published As

Publication number Publication date
JPH07235438A (ja) 1995-09-05
US5168096A (en) 1992-12-01
EP0448482A1 (de) 1991-09-25
JP2986942B2 (ja) 1999-12-06
CA2038639A1 (en) 1991-09-23
DE69114160T2 (de) 1996-06-27
FR2660107A1 (fr) 1991-09-27
DE69114160D1 (de) 1995-12-07
FR2660107B1 (fr) 1994-07-29

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