EP0289680B1 - Dauermagnet und dessen Herstellungsverfahren - Google Patents

Dauermagnet und dessen Herstellungsverfahren Download PDF

Info

Publication number
EP0289680B1
EP0289680B1 EP87308666A EP87308666A EP0289680B1 EP 0289680 B1 EP0289680 B1 EP 0289680B1 EP 87308666 A EP87308666 A EP 87308666A EP 87308666 A EP87308666 A EP 87308666A EP 0289680 B1 EP0289680 B1 EP 0289680B1
Authority
EP
European Patent Office
Prior art keywords
magnet
permanent magnet
alloy
cast
ppm
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.)
Expired - Lifetime
Application number
EP87308666A
Other languages
English (en)
French (fr)
Other versions
EP0289680A2 (de
EP0289680A3 (en
Inventor
Koji Akioka
Osamu Kobayashi
Tatsuya Shimoda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seiko Epson Corp
Original Assignee
Seiko Epson Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP62104623A external-priority patent/JP2725004B2/ja
Application filed by Seiko Epson Corp filed Critical Seiko Epson Corp
Publication of EP0289680A2 publication Critical patent/EP0289680A2/de
Publication of EP0289680A3 publication Critical patent/EP0289680A3/en
Application granted granted Critical
Publication of EP0289680B1 publication Critical patent/EP0289680B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • 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

Definitions

  • the present invention relates to a permanent magnet which comprises a rare earth element, iron and boron, and a method of producing the same.
  • rare earth element R
  • Y Yttrium
  • a permanent magnet is one of the major components used in the electrical and electronic field, e.g. in various household electrical appliances and in the peripheral console units of large computers.
  • Typical permanent magnets now in use include an alnico hard ferrite magnet and a rare earth element -transition metal magnet.
  • an R - Co permanent magnet and an R - Fe - B permanent magnet which are rare earth element - transition metal magnets, can produce a high magnetic performance, so that many researches have hitherto been made on them.
  • Reference 1 Japanese Patent Laid-Open Specification No. 46008/1984.
  • Reference 3 Japanese Patent Laid-Open Specification No. 211549/1984.
  • Reference 5 Japanese Patent Laid-Open Specification No. 100402/1985.
  • an alloy ingot is first made by melting and casting, and is pulverized to a particle diameter of about 3 »m.
  • the pulverized powder is kneaded with a binder, and pressed in a magnetic field to obtain a moulded body.
  • the moulded body is sintered at approximately 1,100°C in an argon gas atmosphere for 1 hour, and thereafter heat treated at approximately 600°C to improve the coercive force.
  • the resin bonding method (2) which incorporates a melt spinning method, rapidly-quenched thin fragments of an R - Fe - B alloy are first produced by a melt spinning apparatus at an optimum substrate velocity.
  • a thus-obtained ribbon-like thin fragment having a thickness of 30 »m is an aggregate of crystal grains having a diameter of not more than 1,000 ⁇ . Since the crystal axes of the crystal grains are distributed isotropically, the thin ribbon is magnetically isotropic. If the thin ribbon is pulverized into an appropriate grain size, kneaded with a resin, and then pressed, an isotropic magnet is obtained.
  • the ribbon-like thin fragments used in the method (2) are pressed at a temperature of about 700°C and under a pressure of not more than 1.4 ton/cm2 in vacuo or in an inert gas. Then this pressed body is next pressed at 700°C and under a pressure of 7 ton/cm2 for several seconds to reduce the thickness to half the initial thickness. Thus, a dense and anisotropic R - Fe - B magnet is obtained.
  • LDC liquid dynamic compaction process
  • the sintering process (1) necessitates the step of powdering an alloy. Since the powder of an R - Fe - B alloy is very reactive to oxygen, it is necessary to handle the charge of the powder used in the sintering process very carefully and an expensive equipment for inert gas, etc. is required.
  • the carbon of a binder has a deleterious influence on the magnetic performance, and is difficult to handle the moulded body called a green body.
  • Both methods (2) and (3) require an expensive vacuum melt spinning apparatus or hot press which has a poor productivity.
  • a magnet produced by the method (2) is isotropic and, hence, it is impossible to obtain a high energy product. This magnet is therefore disadvantageous both in its temperature characteristics and in use.
  • the method (3) uses a two-stage hot pressing process. Therefore, the productivity is very poor, and it cannot make the best use of an R - Fe - B magnet which, as stated above, is inexpensive in its material cost.
  • the LDC process also has the problems of requiring an expensive equipment and having a poor productivity.
  • the alloy contains Nd and/or Pr.
  • the invention also comprises a method of making a permanent magnet as recited in Claim 9.
  • the magnet is heat treated at a temperature not lower than 250°C.
  • the magnet is subjected to hot processing at a temperature not lower than 500°C so as to make the magnet anisotropic.
  • the method comprises hot processing the magnet at a temperature not lower than 500°C so as to make the magnet anisotropic, and heat treating the magnet at a temperature not lower than 250°C.
  • a preferred composition of a permanent magnet containing at least one rare earth element, iron and boron as basic ingredients is 8 to 30 atm% of a rare earth element or elements, 2 to 28 atm% of boron, the balance being substantially iron.
  • rare earth element or elements employed Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu are usable. Above all, Nd and Pr are preferable.
  • Two or more of these rare earth elements may be used in combination.
  • impurities inevitable in the manufacturing process may be contained in the alloy, and cobalt may be added, e.g. in an amount of up to 40 atm%, in order to raise the Curie temperature.
  • cobalt may be added, e.g. in an amount of up to 40 atm%, in order to raise the Curie temperature.
  • the carbon content and the oxygen content in the magnet are set at no more than 400 ppm and 1,000 ppm, respectively, because if they exceed 400 ppm and 1,000 ppm, respectively, the magnetic performance is lowered.
  • the grain diameter of the crystal grains must be appropriate.
  • the average grain diameter of the magnet after casting exceeds 150 »m, the coercive force does not reach that of a ferrite magnet, namely 4 KOe, even after hot processing, and such a R - Fe - B alloy cannot be said to be a practical permanent magnet alloy. Therefore, the average grain diameter must be not more than 150 »m.
  • the grain diameter can be controlled by varying the cooling temperature by altering the material of a mould, the heat capacity of the mould, etc.
  • a heat treatment after casting is necessary for diffusing the Fe phase which exists as the primary crystal in the cast alloy, thereby elminating a magnetically soft phase. It goes without saying that a similar heat treatment carried out after hot processing is effective for improving the magnetic properties.
  • the hot processing at a temperature of not lower than 500°C is effective for orientating the crystal axes of the crystal grains to make the magnet anisotropic and for making the crystal grains finer, thereby greatly enhancing the magnetic properties.
  • Table 1 shows the compositions, in atm%, of permanent magnets containing various rare earth elements, iron, boron as the basic ingredients which were produced in the following procedure.
  • An alloy having a desired composition was melted in an Ar atmosphere in an induction furnace and cast into various moulds at 1,000°C. When 20 minutes had passed after casting the ingots were taken out.
  • the alloy contained a rare earth metal having a purity of 95% (the impurities being mainly other rare earth metals), and the alloy contained a transition metal having a purity of not less than 99.9%.
  • boron a ferroboron alloy was used.
  • the cast alloy was subjected to heat treatment at a temperature of not lower than 250°C (in Example 1, at 1,000°C for 24 hours), and was then cut to obtain a permanent magnet.
  • the magnetic performance and the average grain diameter of the magnet obtained by casting each composition into an iron mould is shown in Table 2 below.
  • the accompanying drawing shows the relationship between the average diameter (»m) after casting and the coercive force (iHc) after hot pressing of the samples Nos. 3 and 4 having the respective compositions shown in Table 1.
  • the grain diameter was controlled by using a water-cooled copper mould, an iron mould, a ceramic mould, etc, and by vibrating the mould. From this result, it is found that it is possible to obtain a permanent magnet by casting while controlling the grain diameter.
  • compositions shown in Table 3 below were cast into a water cooled copper mould in the same way as in Example 1, and thereafter the ingots were hot pressed at 1,000°C to make the respective permanent magnets anisotropic.
  • the average diameter and the magnetic performance after heat treatment, and the average diameter and the magnetic performance after hot pressing, of each magnet are shown in Table 4 below.
  • the hot pressing makes the grain diameters smaller and greatly enhances the magnetic performance, and the heat treatment improves the magnetic performance.
  • the casting method was adopted,and the carbon content and the oxygen content in the magnet obtained were not more than 400 ppm and not more than 1,000 ppm, respectively.
  • the permanent magnets of the present invention can be produced in bulk with a satisfactory coercive force without the need for pulverizing a cast ingot, it is possible to greatly simplify the manufacturing steps, and a high-performance and low-cost permanent magnet can be obtained.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Soft Magnetic Materials (AREA)

Claims (13)

  1. Permanentmagnet, bestehend aus einem Körper, der gegossen ist aus mindestens einem Seltenerdelement, Eisen und Bor,
    dadurch gekennzeichnet,
    daß der mittlere Korndurchmesser der Kristalle des Magneten nicht mehr als 150 »m ist und der Kohlenstoff- und Sauerstoffgehalt des Magneten nicht mehr als 400 ppm bzw. 1.000 ppm ist.
  2. Permanentmagnet nach Anspruche 1,
    dadurch gekennzeichnet,
    daß die Legierung Nd und/oder Pr enthält.
  3. Permanentmagnet nach Anspruch 1 oder 2,
    dadurch gekennzeichnet,
    daß die Legierung 8 bis 30 Atom-% eines Seltenerdelements oder von Seltenerdelementen und 2 bis 28 Atom-% Bor enthält, wobei der Rest zumindest hauptsächlich Eisen ist.
  4. Permanentmagnet nach Anspruch 3,
    dadurch gekennzeichnet,
    daß der Rest ganz aus Eisen und Verunreinigungen besteht.
  5. Permanentmagnet nach Anspruch 3,
    dadurch gekennzeichnet,
    daß der Rest Kobalt enthält.
  6. Permanentmagnet nach Anspruch 5,
    dadurch gekennzeichnet,
    daß der Kobalt-Gehalt der Legierung 40 Atom-% nicht überschreitet.
  7. Permanentmagnet nach einem der Ansprüche 3, 5 oder 6,
    dadurch gekennzeichnet,
    daß der Rest eines oder mehrere der Elemente Al, Cr, Mo, W, Nb, Ta, Zr, Hf und Ti enthält.
  8. Permanentmagnet nach Anspruch 7,
    dadurch gekennzeichnet,
    daß der Rest nicht mehr als 10 Atom-% des einen oder der mehreren Elemente enthält.
  9. Verfahren zur Herstellung eines Permanentmagneten, folgende Schritte aufweisend:
    Gießen eines geschmolzenen Materials, das mindestens ein Seltenerdelement, Eisen und Bor enthält, zur Erzeugung eines Gußkörpers, und weiteres Behandeln des Gußkörpers zur Erzeugung des Permanentmagneten,
    dadurch gekennzeichnet,
    daß der mittlere Korndurchmesser der Kristalle des Magneten nicht mehr als 150 »m beträgt und der Kohlenstoff- und Sauerstoffgehalt des Magneten nicht mehr als 400 ppm bzw. 1.000 ppm beträgt.
  10. Verfahren nach Anspruch 9,
    dadurch gekennzeichnet,
    daß die Legierung, nachdem sie gegossen wurde, bei einer Temperatur nicht unterhalb von 250°C wärmebehandelt wird.
  11. Verfahren nach Anspruch 9 oder 10,
    dadurch gekennzeichnet,
    daß die gegossene Legierung bei einer Temperatur nicht unterhalb von 500°C einer Heißbehandlung unterzogen wird, um den Magneten anisotrop zu machen.
  12. Verfahren nach einem der Ansprüche 9 bis 11,
    dadurch gekennzeichnet,
    daß das Gießen in einer Ar-Atmosphäre durchgeführt wird.
  13. Verfahren nach einem der Ansprüche 9 bis 12,
    dadurch gekennzeichnet,
    daß das geschmolzene Material in eine wassergekühlte Kupferkokille gegossen wird.
EP87308666A 1987-04-30 1987-09-30 Dauermagnet und dessen Herstellungsverfahren Expired - Lifetime EP0289680B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP104623/87 1987-04-30
JP62104623A JP2725004B2 (ja) 1986-04-30 1987-04-30 永久磁石の製造方法

Publications (3)

Publication Number Publication Date
EP0289680A2 EP0289680A2 (de) 1988-11-09
EP0289680A3 EP0289680A3 (en) 1990-06-06
EP0289680B1 true EP0289680B1 (de) 1994-06-22

Family

ID=14385570

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87308666A Expired - Lifetime EP0289680B1 (de) 1987-04-30 1987-09-30 Dauermagnet und dessen Herstellungsverfahren

Country Status (4)

Country Link
EP (1) EP0289680B1 (de)
KR (1) KR930002559B1 (de)
AT (1) ATE107795T1 (de)
DE (1) DE3750136T2 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6790296B2 (en) * 2000-11-13 2004-09-14 Neomax Co., Ltd. Nanocomposite magnet and method for producing same

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0175214B2 (de) * 1984-09-14 1993-12-29 Kabushiki Kaisha Toshiba Permanentmagnetische Legierung und Methode zu ihrer Herstellung
FR2586323B1 (fr) * 1985-08-13 1992-11-13 Seiko Epson Corp Aimant permanent a base de terres rares-fer
JPS6247455A (ja) * 1985-08-28 1987-03-02 Sumitomo Special Metals Co Ltd 高性能永久磁石材料

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JOURNAL DE PHYSIQUE, COLLOQUE C8, Supplément au n° 12, Tome 49, décembre 1988, pages 631-632 *

Also Published As

Publication number Publication date
EP0289680A2 (de) 1988-11-09
DE3750136D1 (de) 1994-07-28
EP0289680A3 (en) 1990-06-06
KR930002559B1 (ko) 1993-04-03
KR880013195A (ko) 1988-11-30
DE3750136T2 (de) 1994-10-06
ATE107795T1 (de) 1994-07-15

Similar Documents

Publication Publication Date Title
US5538565A (en) Rare earth cast alloy permanent magnets and methods of preparation
JPH04245403A (ja) 希土類−Ｆｅ−Ｃｏ−Ｂ系異方性磁石
JP2558095B2 (ja) 希土類一鉄系永久磁石の製造方法
JPH06207203A (ja) 希土類永久磁石の製造方法
CN1024968C (zh) 一种稀土-铁-硼永磁材料的制取方法
US5186761A (en) Magnetic alloy and method of production
EP0288637B1 (de) Dauermagnet und sein Herstellungsverfahren
EP0289680B1 (de) Dauermagnet und dessen Herstellungsverfahren
US5460662A (en) Permanent magnet and method of production
JP2725004B2 (ja) 永久磁石の製造方法
JP2530185B2 (ja) 永久磁石の製造法
JP3178848B2 (ja) 永久磁石の製造方法
JP2857824B2 (ja) 希土類−鉄系永久磁石の製造方法
EP0599815B1 (de) Magnetische Legierung und Herstellungsverfahren
JP4133315B2 (ja) 希土類磁石の製造法、希土類磁石用原料合金及び粉末
JPH07123083B2 (ja) 鋳造希土類―鉄系永久磁石の製造方法
JPH0521219A (ja) 希土類永久磁石の製造方法
JP2730441B2 (ja) 永久磁石用合金粉末の製造方法
JPH04143221A (ja) 永久磁石の製造方法
JP2992808B2 (ja) 永久磁石
JPH01175211A (ja) 希土類−鉄系永久磁石の製造方法
JPH08250312A (ja) 希土類−鉄系永久磁石およびその製造方法
JPH02118054A (ja) 永久磁石材料
JPS5848607A (ja) 希土類コバルト磁石の製造方法
JP2003243211A (ja) 磁気異方性に優れた希土類磁石粉末の製造方法

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT CH DE FR GB IT LI NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT CH DE FR GB IT LI NL

17P Request for examination filed

Effective date: 19901120

17Q First examination report despatched

Effective date: 19920311

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT CH DE FR GB IT LI NL

REF Corresponds to:

Ref document number: 107795

Country of ref document: AT

Date of ref document: 19940715

Kind code of ref document: T

ITF It: translation for a ep patent filed

Owner name: JACOBACCI CASETTA & PERANI S.P.A.

REF Corresponds to:

Ref document number: 3750136

Country of ref document: DE

Date of ref document: 19940728

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20000913

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010930

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050930

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20060908

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20060917

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20060927

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20060928

Year of fee payment: 20

Ref country code: CH

Payment date: 20060928

Year of fee payment: 20

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20070929

NLV7 Nl: ceased due to reaching the maximum lifetime of a patent

Effective date: 20070930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20070930