EP0144112B1 - Alliages magnétiques à produit d'énergie élevé à base de terres rares, métaux de transition et bor - Google Patents

Alliages magnétiques à produit d'énergie élevé à base de terres rares, métaux de transition et bor Download PDF

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Publication number
EP0144112B1
EP0144112B1 EP84300741A EP84300741A EP0144112B1 EP 0144112 B1 EP0144112 B1 EP 0144112B1 EP 84300741 A EP84300741 A EP 84300741A EP 84300741 A EP84300741 A EP 84300741A EP 0144112 B1 EP0144112 B1 EP 0144112B1
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EP
European Patent Office
Prior art keywords
alloy
alloys
magnetic
boron
rare earth
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Expired
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EP84300741A
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German (de)
English (en)
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EP0144112A1 (fr
Inventor
John Joseph Croat
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Motors Liquidation Co
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Motors Liquidation Co
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • 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

Definitions

  • TM herein is used to symbolize a transition metal taken from the group consisting of iron or iron mixed with cobalt, or iron and small amounts of such other metals as nickel, chromium or manganese.
  • Iron is preferred for its relatively high magnetic remanence and low cost. A substantial amount may be mixed with iron without adverse effect on the magnetic properties.
  • Nickel, chromium and manganese are also transition metals. However, their inclusion in amounts greater than 10 percent have generally been found to have a deleterious effect on permanent magnetic properties of Nd-Fe-B alloys.
  • the most preferred alloys contain the rare earth elements Nd and/or Pr and the transition metal element, Fe.
  • the superior properties of these light rare earth-iron combinations are due, at least in part, to ferromagnetic coupling between the light rare earth elements and Fe. That is, in optimum alloys the orbital magnetic moments (l) of the rare earths align in the same parallel direction as the spin moments of the iron (S) so that the total moment (7) equals L+
  • the total magnetic moment of the ferromagnetically coupled light rare earth-iron alloys is, therefore, greater than that of antiferromagnetically coupled heavy rare earth-iron alloys.
  • the rare earth element, samarium may couple ferro or antiferromagnetically with iron, behaving therefore as both a light and a heavy rare earth element within the context of this invention.
  • Permanent magnet alloys in accordance with the invention were made by mixing suitable weight portions of elemental forms of the rare earths, transition metals and boron. The mixtures were arc melted to form alloy ingots. The alloy was in turn remelted in a quartz crucible and expressed through a small nozzle onto a rotating chill surface. This produced thin ribbons of alloy.
  • the process is generally referred to in the art as "melt spinning" and is also described in British Patent No. 2 100 286 B.
  • melt spinning the quench rate of the melt spun material can be varied by changing the linear speed of the quench surface. By selection of suitable speed ranges products were obtained that exhibited high intrinsic magnetic coercivities and remanence.
  • This invention relates to making improved magnetically hard rare earth-transition metal compositions incorporating small amounts of the element boron.
  • the invention also relates to quenching molten mixtures of the constituent elements at a rate between that which yields a magnetically soft amorphous material and a magnetically soft crystalline material.
  • H refers to the strength of an applied magnetic field
  • H cl is the intrinsic coercive force or reverse field required to bring a magnetized sample having magnetization M back to zero magnetization
  • M is the magnetization of a sample in electromagnetic units
  • M s is the saturation magnetization or the maximum magnetization that can be induced in a sample by an applied magnetic field
  • B r is the remanent magnetic induction
  • BH is the energy product
  • T is temperature in degrees Kelvin unless otherwise indicated.
  • melt spinning is a well known process which has been used to make "meltglasses" from high alloy steels. As it relates to this invention, melt spinning entails mixing suitable weight portions of the constituent elements and melting them together to form an alloy of a desired composition. Arc melting is a preferred technique for experimental purposes because it prevents any contamination of the alloys from the heating vessel.
  • alloy ingots were broken into chunks small enough to fit inside a spin melting tube (crucible or tundish) made of quartz. Ceramic, or other suitable refractory materials could be used. Each tube had a small orifice in its bottom through which an alloy could be ejected. The top of the tube was sealed and provided with means for containing pressurized gas in the tube above a molten alloy. A heating coil was disposed around the portion of the tube containing the alloy to be melt spun. When the coil was activated, the chunks of alloy within the tube melted and formed a fluid mass.
  • the disc speed (V s) is the speed in metres per second of a point on the chill surface of the melt spinner's quench disc as it rotates at a constant rotational velocity. Because the chill disc is much more massive than the alloy ribbon, it acts as an infinitely thick heat sink for the metal that solidifies on it. The disc may be cooled by any suitable means to prevent heat build-up during long runs.
  • the terms "melt-spinning” or “melt-spun” as used herein refer to the process described above as well as any like process which achieves a like result.
  • the critical element of the melt-spinning process is the controlled quenching of the molten alloy to produce the desired very fine crystalline microstructure. While melt spinning is a preferred method of making the subject boron enhanced RE-TM magnet materials, other comparable methods may be employed.
  • X-ray data supports the hypothesis that the hard magnetic phase is, in fact, very finely crystalline. Scanning electron microscopy results indicate that the optimum average crystallite size is between about 20 and 400 nanometers. It is believed that such small crystallite size is nearly commensurate with optimum single domain size for the subject RE-Fe-B alloys.
  • the rare earth elements include scandium and yttrium in group IIIA of the period table as well as the lanthanide series elements from atomic No. 57 (lanthanum) through atomic No. 71 (lutetium).
  • the f-orbital of the preferred rare earth constituent elements or alloys should not be empty, full or half full. That is, there should not be zero, seven or fourteen electrons in the f-orbital of the alloyed rare earth constituent.
  • the preferred rare earth elements for use in this invention are two lower atomic weight members of the lanthanide series, neodymium and praseodymium. These elements are also commonly referred to as light rare earth elements. Nd and Pr are among the most abundant, least expensive, and have the highest magnetic moments of the light rare earths. The elements Nd and Pr also couple ferromagnetically with iron (total moment,
  • the relative amounts of RE, TM and B alloyed together are expressed herein in terms of atomic fractions or percents. A distinction is made herein between atomic fractions and atomic weight fractions.
  • one atomic weight unit of the composition having the atomic fraction formula Ndo. 4 (Feo. 95 Bo.os)o. 6 would comprise by weight: which expressed as weight fractions or weight percents of the constituents is:
  • the preferred compositional range for the subject hard magnet alloys of this invention is about 10 to 20 atomic percent rare earth elements with the balance being transition metal elements and a small amount (less than about 10 and preferably less than about 7 atomic percent total) boron. Higher percentages of the rare earth elements are possible but may adversely affect the magnetic energy product. Small amounts of other elements may be present so long as they do not materially- adversely affect the practice of the invention. The invention will be better understood in view of the following examples.
  • alloys of neodymium and iron were made by mixing substantially pure commercially available forms of the elements in suitable weight proportions. The mixtures were arc melted to form alloy ingots. The amount of neodymium was maintained in each alloy at an atomic fraction of 0.4. The iron and boron constituents together made up an atomic fraction of 0.6. The atomic fraction of boron, based on the amount of iron present was varied from 0.01 to 0.03. Each of the alloys was melt spun by the method described above. The quench rate for each alloy was changed by varying the surface velocity of the quench wheel. About four grams of ribbon were made for each sample.
  • overquenched ribbon (V s >20 m/s, e.g.) can be affected as will be described hereinafter to induce coercivity and remanence commensurate with optimally quenched alloy.
  • Figure 7 shows demagnetization curves for melt spun Nd 0.2 (Fe 0.96 B 0.04 ) 0.8 alloy as a function of the initial magnetizing field.
  • it is possible that higher remanence magnetization and H c could be achieved for the subject RE-Fe-B compositions given a stronger magnetizing field strong enough to induce magnetic saturation.
  • Table 11 shows the intrinsic coercivity, magnetic remanence and energy products for neodymium transition metal boron alloys. The reported values are for the best overall combination of coercivity remanence and energy product where the aim is to produce a permanent magnet. Generally, such data represent the squarest shaped second quadrant demagnetization curve.
  • the major phase of the magnetic alloys has a tetragonal crystal structure where the length of the a axis is about 8.78 angstroms and the c axis is about 12.18 angstroms.
  • the composition of this phase is RE 2 Fe 14 B 1 as determined by neutron diffraction analysis. Efficient and economical means of making the subject alloys in forms adapted for the production of a new breed of permanent magnets have also been discovered. It is expected that these magnets will find application in many industrial environments.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Hard Magnetic Materials (AREA)

Claims (6)

1. Alliage pour aimant permanent contenant au moins un élément des terres rares, au moins un métal de transition et du bore, dans lequel l'alliage contient une phase cristalline tétragonale prépondérante ayant une formule atomique RE2TM14B, dans laquelle RE représente un ou plusieurs éléments des terres rares, le néodyme et/ou le praséodyme formant au moins 60 atomes pour cent des éléments des terres rares présents au total, et TM représente un ou plusieurs métaux de transition, le fer formant au moins 60 atomes pour cent de la quantité totale des métaux de transition présents, et l'alliage a une dimension moyenne de cristallites qui est comprise dans la plage allant de 20 à 400 nanomètres (nm).
2. Alliage pour aimant permanent selon la revendication 1, dans lequel la phase cristalline tétragonale a la formule atomique RE2Fe14B1 dans laquelle RE représente le néodyme et/ou le praséodyme.
3. Alliage pour aimant permanent selon la revendication 2, dans lequel la longueur de l'axe cristallographique c de la phase cristalline tétragonale est d'environ 1,218 nm (12,18 Â) et la longueur de l'axe a de la phase cristalline tétragonale est d'environ 0,878 nm (8,78 Â).
4. Alliage pour aimant permanent selon l'une quelconque des revendications 1, 2 et 3, dans lequel l'axe cristallographique c de la phase cristalline tétragonale est l'axe d'aimantation préférentielle.
5. Alliage pour aimant permanent selon l'une quelconque des revendications précédentes, dans lequel la phase cristalline tétragonale a la formule atomique Nd2Fe14B1.
6. Alliage pour aimant permanent selon l'une quelconque des revendications 1 à 4, dans lequel la phase cristalline tétragonale a la formule atomique Pr2Fe14B1.
EP84300741A 1983-10-26 1984-02-07 Alliages magnétiques à produit d'énergie élevé à base de terres rares, métaux de transition et bor Expired EP0144112B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US54472883A 1983-10-26 1983-10-26
US544728 1983-10-26

Publications (2)

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EP0144112A1 EP0144112A1 (fr) 1985-06-12
EP0144112B1 true EP0144112B1 (fr) 1989-09-27

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EP (1) EP0144112B1 (fr)
BR (1) BR8400917A (fr)
DE (1) DE3479940D1 (fr)
MX (1) MX167656B (fr)
ZA (1) ZA841312B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103668007A (zh) * 2013-12-19 2014-03-26 南京信息工程大学 一种具有高饱和磁感应强度微晶合金薄带及制备方法

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6136099A (en) * 1985-08-13 2000-10-24 Seiko Epson Corporation Rare earth-iron series permanent magnets and method of preparation
US5125988A (en) * 1987-03-02 1992-06-30 Seiko Epson Corporation Rare earth-iron system permanent magnet and process for producing the same
US5538565A (en) * 1985-08-13 1996-07-23 Seiko Epson Corporation Rare earth cast alloy permanent magnets and methods of preparation
FR2586323B1 (fr) * 1985-08-13 1992-11-13 Seiko Epson Corp Aimant permanent a base de terres rares-fer
DE3682048D1 (de) * 1986-01-10 1991-11-21 Ovonic Synthetic Materials Permanentmagnetische legierung.
CA1269029A (fr) * 1986-01-29 1990-05-15 Peter Vernia Fabrication d'un aimant permanent en alliage de metal de transition de terre rare et de bore
EP0243641B1 (fr) * 1986-03-27 1990-07-25 Siemens Aktiengesellschaft Procédé de préparation d'un matériau à propriété magnétique permanente à partir de poudre
ATE77172T1 (de) * 1986-07-28 1992-06-15 Crucible Materials Corp Verfahren zur herstellung eines voellig dichten gegenstandes.
EP0260746A1 (fr) * 1986-09-17 1988-03-23 Koninklijke Philips Electronics N.V. Méthode de fabrication de copeaux de matériau magnétique ayant une orientation préférentielle des cristallites, copeaux et aimants fabriqués à partir de ceux-ci
US5213631A (en) * 1987-03-02 1993-05-25 Seiko Epson Corporation Rare earth-iron system permanent magnet and process for producing the same
EP0284832A1 (fr) * 1987-03-20 1988-10-05 Siemens Aktiengesellschaft Procédé de production d'un matériau magnétique anisotrope à base de Fe, B, et un métal de terre rare
DE3709138C2 (de) * 1987-03-20 1996-09-05 Siemens Ag Verfahren zur Herstellung eines magnetischen Werkstoffes aus pulverförmigen Ausgangskomponenten
DE3832472A1 (de) * 1988-09-23 1990-03-29 Siemens Ag Verfahren zur herstellung eines werkstoffes mit einer hartmagnetischen phase aus pulverfoermigen ausgangskomponenten
GB2308384B (en) * 1995-12-21 1999-09-15 Univ Hull Magnetic materials
US10861629B1 (en) * 2017-03-03 2020-12-08 Apple Inc. Solid state deposition of magnetizable materials

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0101552A2 (fr) * 1982-08-21 1984-02-29 Sumitomo Special Metals Co., Ltd. Matériaux magnétiques, aimants permanents et procédés pour leur production
EP0106948A2 (fr) * 1982-09-27 1984-05-02 Sumitomo Special Metals Co., Ltd. alliages magnétisables permanentement, matériaux magnétiques et aimant permanent contenant FeBR ou (Fe,Co)BR (R=terre rare)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4496395A (en) * 1981-06-16 1985-01-29 General Motors Corporation High coercivity rare earth-iron magnets
US4374665A (en) * 1981-10-23 1983-02-22 The United States Of America As Represented By The Secretary Of The Navy Magnetostrictive devices

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0101552A2 (fr) * 1982-08-21 1984-02-29 Sumitomo Special Metals Co., Ltd. Matériaux magnétiques, aimants permanents et procédés pour leur production
EP0106948A2 (fr) * 1982-09-27 1984-05-02 Sumitomo Special Metals Co., Ltd. alliages magnétisables permanentement, matériaux magnétiques et aimant permanent contenant FeBR ou (Fe,Co)BR (R=terre rare)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103668007A (zh) * 2013-12-19 2014-03-26 南京信息工程大学 一种具有高饱和磁感应强度微晶合金薄带及制备方法

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Publication number Publication date
DE3479940D1 (en) 1989-11-02
ZA841312B (en) 1985-09-25
BR8400917A (pt) 1985-06-11
EP0144112A1 (fr) 1985-06-12
MX167656B (es) 1993-04-01

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