EP0284832A1 - Procédé de production d'un matériau magnétique anisotrope à base de Fe, B, et un métal de terre rare - Google Patents

Procédé de production d'un matériau magnétique anisotrope à base de Fe, B, et un métal de terre rare Download PDF

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Publication number
EP0284832A1
EP0284832A1 EP88103535A EP88103535A EP0284832A1 EP 0284832 A1 EP0284832 A1 EP 0284832A1 EP 88103535 A EP88103535 A EP 88103535A EP 88103535 A EP88103535 A EP 88103535A EP 0284832 A1 EP0284832 A1 EP 0284832A1
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EP
European Patent Office
Prior art keywords
earth metal
magnetic
material system
crystallization
rare earth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP88103535A
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German (de)
English (en)
Inventor
Joachim Dr. Wecker
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Siemens AG
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Siemens AG
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Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0284832A1 publication Critical patent/EP0284832A1/fr
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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
    • 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 an anisotropic magnetic material from a material system with at least the three material components iron (Fe), boron (B) and a rare earth metal (SE), in which method rapid solidification of an alloy melt of the desired composition and subsequently a treatment for generating magnetic anisotropy is carried out.
  • Fe iron
  • B boron
  • SE rare earth metal
  • Nd-Fe-B magnetic materials show remanence values and energy densities that are significantly higher than those of the known Sm-Co-based alloys. It is therefore to be expected that they will replace the conventional Sm-Co materials in many applications.
  • the excellent magnetic properties of this three-component system are based on the tetragonal intermetallic phase Nd2Fe14B. This is a phase which is sometimes also referred to as the theta phase and has a uniaxial crystal anisotropy, the anisotropy field H A at 300 K being approximately 75 kOe.
  • Anisotropic Nd-Fe-B magnetic materials are often produced using powder metallurgy (cf. EP-A-0 126 179). According to this method, an alloy of the desired composition is first ground so far that the powder grains are the size of single-range particles. These powder grains with grain sizes between 2 and 4 ⁇ m are then aligned in a magnetic field, for example pre-compacted by isostatic pressing and then sintered to form a high-density body. With a final heat treatment, the magnetic properties are then optimized.
  • isotropic strips of the desired composition are first produced by rapid solidification of an alloy melt. These strips with a fine crystalline structure are then compacted into an isotropic dense body by pressing at temperatures around 700 ° C. A subsequent hot deformation at about 700 ° C by about 50% then leads to an anisotropic texture with the magnetically easy c-direction parallel to the pressing direction (see also "Appl.Phys.Lett.” 46 (8), April 15, 1985, pages 790 and 791).
  • the object of the present invention is therefore to further develop the method of the type mentioned at the outset in such a way that it can be used to produce anisotropic magnetic materials with the material components Fe, B and a rare earth metal which have a greater coercive force.
  • Nd-Fe-B In the ternary system Nd-Fe-B, methods fail to set a preferred anisotropy by heat treatment of the initially amorphous alloy in the magnetic field at the low Curie temperature T c of approx. 315 ° C. compared to the crystallization temperature T k of approx. 550 ° C.
  • T c Curie temperature
  • T k crystallization temperature
  • co-additives increase the Curie temperature.
  • the coercive force deteriorated, so that, for example, an improvement in temperature stability by Co alone is not possible.
  • the invention is based on the knowledge that the Nd2 (Fe 1-x Co x ) 14B phase, which forms in the early stages of crystallization of the corresponding amorphous alloy, has a Curie temperature T c comparable to the equilibrium phase. This is not immediately obvious, since in the course of the crystallization (metastable) phases with a different structure and / or a different composition can initially arise, which therefore also have different physical properties than those with regard to the structure and the concentration in the thermodynamic equilibrium present phase.
  • Figure 1 shows for the system Nd- (Fe, Co) -B the dependence of the Curie temperature and the crystallization temperature on the Co concentration.
  • Nd- (Fe, Co) -B the dependence of the Curie temperature and the crystallization temperature on the Co concentration.
  • the coercive field strength and the remanence as a function of the Co concentration are shown in the diagram in FIG.
  • the exemplary embodiment is based on a magnetic material of the 4-substance system SE- (Fe, Co) -B, with SE Nd selected as the rare earth metal.
  • SE- (Fe, Co) -B SE- (Fe, Co) -B
  • SE Nd selected as the rare earth metal.
  • Nd1 N (Fe 1-x Co x ) 77B8 with 0.1 ⁇ x ⁇ 0.6, for example the alloy Nd15 (Fe 0.7 Co 0.3 ) 77B8 the starting materials with sufficient Purity in the desired ratio under a Ti-cleaned argon atmosphere was inductively melted into a master alloy. Pyrolytic BN or Al2O3 crucibles are used. Melting in an arc furnace is also possible.
  • melt-spinning a process which is known from the production of amorphous metal alloys (cf. for example "Zeitschrift für Metallischen Metallischen” Vol. 69, 1978, Book 4, pages 212 to 220).
  • a protective gas such as Argon or under vacuum the master alloy e.g. melted in a quartz crucible at high frequency and then sprayed through a nozzle onto a rapidly rotating copper drum.
  • the substrate speed, i.e. the speed of rotation of the copper drum is typically above 30 m / sec. In this way, the required cooling rate of more than 106 K / sec is achieved.
  • the amorphous phase is characterized by a diffuse X-ray diffraction diagram and a symmetrical hysteresis loop with coercive field strengths below 100 Oe.
  • the intermediate product obtained in tape form is then comminuted into smaller pieces of tape or into powders.
  • the particles thus formed are then e.g. in quartz tubes under an argon atmosphere, optionally in the presence of additional getter materials such as e.g. Zr for setting residual oxygen, melted down.
  • the intermediate product thus prepared in particle form is then crystallized by means of a suitable heat treatment.
  • the temperature is chosen so that it is above the crystallization temperature T k , but below the Curie temperature T c .
  • T k crystallization temperature
  • T c Curie temperature
  • This heat treatment is said to be in a magnetic direct field can be made so as to set the desired magnetic anisotropy.
  • a value between 0.5 and 100 kOe is advantageously chosen for the field strength.
  • the temperature to be selected must of course also be below the temperature T s at which the uniaxial preferred direction changes to a planar preferred plane (cf. "Journ. Of Magnetism and Magn.Mat.”, Vol. 65, 1987, pages 139 to 144 ).
  • the powder crystallized in this way is aligned in a further external magnetic constant field.
  • the field strength of this alignment field can be significantly lower than that of the field created during the crystallization process and can be, for example, at least 1, preferably at least 5 kOe.
  • Simultaneously with this alignment of the powder particles they are e.g. can be mechanically fixed by pouring quick-curing synthetic resin. Appropriate magnets can then be built up with the body made of the special anisotropic magnetic material.
  • the crystallized particles can also be aligned in the magnetic field and simultaneously compacted into a dense body by mechanical pressing processes.
  • a workpiece of the desired geometry can first be pressed out of the amorphous material, so that the field crystallization is carried out only afterwards.
  • the material can also give complicated preferred geometries. For example, Create magnetic ring bodies with a radial preferred direction.
  • the method according to the invention can be used for any alloy Concentrations are used as long as it is ensured that the hard magnetic phase Nd2 (Fe, Co) 14B is formed at least for the most part during crystallization.
  • the Co concentration, based on the Fe content, should be between 0.1 and 0.60, preferably between 0.15 and 0.5. This results in Curie temperatures between 430 and 630 ° C.
  • the corresponding temperature conditions for the material Nd15 (Fe 1-x Co x ) 77B8 can be seen in the diagram of Figure 1.
  • the Co concentration x is a substituted Fe component on the abscissa and the associated temperatures T in ° C are plotted on the ordinate.
  • Curve I represents the Curie temperature T c of the crystallizing Nd2 (Fe, Co) 14-B phase and curve II the crystallization temperature T k of corresponding amorphous bands for a heating rate of 40 K / min. Since, according to the invention, the heat treatment for crystallization is to take place above the crystallization temperature T k , but below the Curie temperature T c , according to the diagram, only Co concentrations with x above 0.3 are possible due to the intended annealing conditions. However, if one selects smaller heating rates or if the crystallization is carried out isothermally for longer annealing times, curve II slips further down in the diagram, so that the required temperature conditions can then be maintained even with correspondingly low Co concentrations.
  • the required theta phase of the 4-substance system SE x (Fe, Co) y B z occurs when a composition of this system is selected, so that the following applies: 10 ⁇ x ⁇ 30, 60 ⁇ y ⁇ 85 and 3 ⁇ z ⁇ 20.
  • x, y and z should have the following relationships: 11 ⁇ x ⁇ 20, 65 ⁇ y ⁇ 80 and 5 ⁇ z ⁇ 20.
  • SE is at least one rare earth metal whose atomic number in the periodic table of the elements is between 58 and 66 (inclusive).
  • Nd is the rare earth metal to be selected SE.
  • another rare earth metal such as praseodymium (Pr) can be selected as well.
  • Pr praseodymium
  • a lighter rare earth metal to be replaced by a heavier rare earth metal such as To at least partially substitute dysprosium (Dy) in order to achieve higher coercive field strengths.
  • the Fe component can optionally also be partially substituted by another metallic element, such as in particular aluminum (Al).
  • another metallic element such as in particular aluminum (Al).
  • the method according to the invention is not limited to intermediate products in particle or powder form.
  • Thin layers produced according to the invention can be provided for the construction of magnetic heads in data storage devices.

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Hard Magnetic Materials (AREA)
EP88103535A 1987-03-20 1988-03-07 Procédé de production d'un matériau magnétique anisotrope à base de Fe, B, et un métal de terre rare Withdrawn EP0284832A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3709140 1987-03-20
DE3709140 1987-03-20

Publications (1)

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EP0284832A1 true EP0284832A1 (fr) 1988-10-05

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EP88103535A Withdrawn EP0284832A1 (fr) 1987-03-20 1988-03-07 Procédé de production d'un matériau magnétique anisotrope à base de Fe, B, et un métal de terre rare

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US (1) US4854979A (fr)
EP (1) EP0284832A1 (fr)
JP (1) JPS63238215A (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8707905D0 (en) * 1987-04-02 1987-05-07 Univ Birmingham Magnets
US5026438A (en) * 1988-07-14 1991-06-25 General Motors Corporation Method of making self-aligning anisotropic powder for magnets
EP0800182B1 (fr) * 1989-09-01 2002-11-13 Masaaki Yagi Bande mince en alliage, magnétiquement douce
US5279349A (en) * 1989-12-29 1994-01-18 Honda Giken Kogyo Kabushiki Kaisha Process for casting amorphous alloy member
GB9215109D0 (en) * 1992-07-16 1992-08-26 Univ Sheffield Magnetic materials and method of making them
DE4324661C2 (de) * 1992-09-29 2000-03-16 Siemens Ag Verfahren zur Herstellung eines Materials mit erhöhtem Magnetowiderstand und Verwendung des so hergestellten Materials
US6019859A (en) * 1994-09-02 2000-02-01 Sumitomo Special Metals Co., Ltd. Iron-based permanent magnets and their fabrication as well as iron-based permanent magnet alloy powders for permanent bonded magnets and iron-based bonded magnets
US5976271A (en) * 1997-04-21 1999-11-02 Shin-Etsu Chemical Co., Ltd. Method for the preparation of rare earth based anisotropic permanent magnet
ES2164528B1 (es) * 1999-04-27 2003-10-16 Univ Barcelona Autonoma Procedimiento para aumentar la coercitividad de un material ferromagnetico.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402770A (en) * 1981-10-23 1983-09-06 The United States Of America As Represented By The Secretary Of The Navy Hard magnetic alloys of a transition metal and lanthanide
EP0144112A1 (fr) * 1983-10-26 1985-06-12 General Motors Corporation Alliages magnétiques à produit d'énergie élevé à base de terres rares, métaux de transition et bor

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3379131D1 (en) * 1982-09-03 1989-03-09 Gen Motors Corp Re-tm-b alloys, method for their production and permanent magnets containing such alloys
US4597938A (en) * 1983-05-21 1986-07-01 Sumitomo Special Metals Co., Ltd. Process for producing permanent magnet materials
JPS60197843A (ja) * 1984-03-17 1985-10-07 Namiki Precision Jewel Co Ltd 永久磁石合金

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402770A (en) * 1981-10-23 1983-09-06 The United States Of America As Represented By The Secretary Of The Navy Hard magnetic alloys of a transition metal and lanthanide
EP0144112A1 (fr) * 1983-10-26 1985-06-12 General Motors Corporation Alliages magnétiques à produit d'énergie élevé à base de terres rares, métaux de transition et bor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
APPLIED PHYSICS LETTERS, Band 44, Nr. 9, 1. Mai 1984, Seiten 925-926, American Institute of Physics, New York, US; R.A. OVERFELT et al.: "Thermal effects of moderate substitions of cobalt for iron in Fe76Pr16B8" *

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JPS63238215A (ja) 1988-10-04

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