US3701695A - Method of manufacturing a permanent magnet - Google Patents

Method of manufacturing a permanent magnet Download PDF

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Publication number
US3701695A
US3701695A US32701A US3701695DA US3701695A US 3701695 A US3701695 A US 3701695A US 32701 A US32701 A US 32701A US 3701695D A US3701695D A US 3701695DA US 3701695 A US3701695 A US 3701695A
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US
United States
Prior art keywords
sintering
manufacturing
permanent magnet
permanent
getter
Prior art date
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Expired - Lifetime
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US32701A
Inventor
Kurt Heinz Jurgen Buschow
Frans Frederik Westendorp
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US Philips Corp
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US Philips Corp
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Classifications

    • 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
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0433—Nickel- or cobalt-based alloys
    • C22C1/0441—Alloys based on intermetallic compounds of the type rare earth - Co, Ni
    • 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
    • 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
    • H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
    • H01F1/0557—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together sintered

Definitions

  • M is a rare earth metal or Th or a combination thereof; R is Co or C0 combined with one or more of the elements Fe, Ni and Cu) by sintering between 800" C. and 1100 C. in the presence of an oxygen getter.
  • oxygen getter examples of such an oxygen getter are Y, Th, Ca, Zr, Gd and Ce.
  • the invention relates to a method of manufacturing a permanent magnet of fine particles having permanentmagnetic properties, the essential constituent of which is a compound of a hexagonal structure whose existence range is integral with the existence range of the compound M R of the system MR, in which M is Co or a combination of Co with one or more of the elements Fe, Ni and Cu and R is one or more of the elements of the rare earth metals and/or Th, a solid body being made by sintering from a powder of permanent-magnetic particles of one or more compounds of M and R.
  • the element Y in this connection is also considered to belong to the rare earths.
  • the resultant permanent magnets may be magnetically isotropic or anisotropic according as the permanent-magnetic particles have been or have not been orientated prior to sintering.
  • a basic powder containing SmCo and SIHzCOq subsequent to orientation in a magnetic field was sintered at 1050 C. for one hour in a He-atmosphere. After sintering the sole compound of Sn and Co left was found to be the permanent-magnetic compound SmCo The resultant body was found to have the following permanent-magnetic properties:
  • the method according to the invention is characterized in that sintering is carried out at a temperature lying between -800 C. and 1200 C. in an inert atmosphere in the presence of a material readily binding reactive gasses, such as oxygen, after which the body obtained is cooled and magnetized in a magnetic field.
  • the resultant higher values of coercive force are mentioned in the following table. This table also indicates which getter is used during sintering.
  • the invention therefore also relates to a permanent magnet manufactured by the method in accordance with the invention.
  • a method of manufacturing a permanent magnet comprising the steps of compacting into a body of given shape and dimensions, a mass of finely-divided material consisting of particles having permanent magnet properties and the essential constituent of which is a compound having a a hexagonal structure and whose existence range is integral with the existence range of the compound M R of the system MR, wherein M is an element selected from the group consisting of cobalt iron, nickel and copper and always includes cobalt and R is an element selected from the group consisting of the rare earths and thorium, and heating said body to a temperature between 800 C. and 1200 C.
  • a getter consisting of an element selected from the group consisting of Y, Ce, La, Th, and Ca to sinter said body into a highly-coherent body having a greater coercive force H,) than a like body prepared in like manner in the absence of a getter, thereafter cooling said body and magnetizing said body.

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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)

Abstract

METHOD OF MANUFACTURING A M5R MAGNET HAVING A VERY HIGH COERCIVE FORCCE (M IS A RARE EARTH METAL OR TH OR A COMBINATION THEREOF; R IS CO OR CO COMBINED WITH ONE OR MORE OF THE ELEMENTS FE, NI AND CU) BY SINTERING BETWEEN 800*C AND 1100* C. IN THE PRESENCE OF AN OXYGEN GETTER, EXAMPLES OF SUCH AN OXYGEN GETTER ARE Y, TH, CA, ZR, GD AND CE.

Description

United States Patent 3,701,695 METHOD OF MANUFACTURING A PERMANENT MAGNET Kurt Heinz Jiirgen Buschow and Frans Frederik Westendorp, Emmasingel, Eindhoven, Netherlands, assignors to US. Philips Corporation, New York, N.Y. No Drawing. Filed Apr. 28, 1970, Ser. No. 32,701 Claims priority, applicatisgnwlzlsgherlands, May 14, 1969,
Int. Cl. H01f 1/08 US. Cl. 148-103 5 Claims ABSTRACT OF THE DISCLOSURE Method of manufacturing a M R magnet having a very high coercive force (M is a rare earth metal or Th or a combination thereof; R is Co or C0 combined with one or more of the elements Fe, Ni and Cu) by sintering between 800" C. and 1100 C. in the presence of an oxygen getter. Examples of such an oxygen getter are Y, Th, Ca, Zr, Gd and Ce.
The invention relates to a method of manufacturing a permanent magnet of fine particles having permanentmagnetic properties, the essential constituent of which is a compound of a hexagonal structure whose existence range is integral with the existence range of the compound M R of the system MR, in which M is Co or a combination of Co with one or more of the elements Fe, Ni and Cu and R is one or more of the elements of the rare earth metals and/or Th, a solid body being made by sintering from a powder of permanent-magnetic particles of one or more compounds of M and R.
The element Y in this connection is also considered to belong to the rare earths.
Such a method is known, for example, from Dutch patent application No. 6807894 laid up for public inspection. The resultant permanent magnets may be magnetically isotropic or anisotropic according as the permanent-magnetic particles have been or have not been orientated prior to sintering.
In the aforesaid publication no examples are given from which details of the sintering process can be derived. It is neither stated which are the magnetic properties of the permanent magnets finally obtained by sintering of the; fine particles.
It has experimentally been found that permanent magnets consisting of sintered fine particles of the kind set forth have satisfactory permanent-magnetic properties if during the sintering process a combination of very specific conditions is satisfied: the sintering temperature has to be chosen in a specific temperature range and sintering has to be performed in an inert atmosphere.
For example, a basic powder containing SmCo and SIHzCOq subsequent to orientation in a magnetic field was sintered at 1050 C. for one hour in a He-atmosphere. After sintering the sole compound of Sn and Co left was found to be the permanent-magnetic compound SmCo The resultant body was found to have the following permanent-magnetic properties:
H =11,200 oersted B,=6,000 G The method according to the invention is characterized in that sintering is carried out at a temperature lying between -800 C. and 1200 C. in an inert atmosphere in the presence of a material readily binding reactive gasses, such as oxygen, after which the body obtained is cooled and magnetized in a magnetic field.
Surprisingly it has been found that if during sintering such a getter is present the coercive force of the resultant magnetic body is considerably higher. Examples of such getters" are Y, Th, Zr, Gd, Ca and rare earths elements.
Sintered bodies made from the same basic powder as mentioned above, which have first been orientated and have subsequently been sintered at 1050 C. in a He-atmosphere for one hour, showed H -values which considerably exceeded 11,200 oe. attained in sintering without a getter. The resultant higher values of coercive force are mentioned in the following table. This table also indicates which getter is used during sintering.
Sintering had been carried out in the presence of Y. Permanent magnets having such high coercive forces are particularly important in uses in which the magnet is exposed to high demagnetizing fields. The invention therefore also relates to a permanent magnet manufactured by the method in accordance with the invention.
We claim:
1. A method of manufacturing a permanent magnet comprising the steps of compacting into a body of given shape and dimensions, a mass of finely-divided material consisting of particles having permanent magnet properties and the essential constituent of which is a compound having a a hexagonal structure and whose existence range is integral with the existence range of the compound M R of the system MR, wherein M is an element selected from the group consisting of cobalt iron, nickel and copper and always includes cobalt and R is an element selected from the group consisting of the rare earths and thorium, and heating said body to a temperature between 800 C. and 1200 C. in an inert atmosphere in the presence of a getter consisting of an element selected from the group consisting of Y, Ce, La, Th, and Ca to sinter said body into a highly-coherent body having a greater coercive force H,) than a like body prepared in like manner in the absence of a getter, thereafter cooling said body and magnetizing said body.
2. A method as claimed in claim 1 in which R is Sm and M is Co.
3. A method as claimed in claim 2 in which the body is heated at a temperature between 1025 C. and 1100 C.
4. A method as claimed in claim 3 in which the inert atmosphere is He.
3 4 5. A method as claimed in claim 4 in which the getter OTHER REFERENCES Westendorp, F. F., et al., Permanent Magnets With References Cited Energy Products of 20 Million Gauss Oersteds, Solid UNITED STATES PATENTS 6 State Communications, 1969, pp. 639-40. 2 54 320 19 R 2 BUSChOW, K. H. 1., Intermetallic Compounds in the 3,051,566 3/1962 g g 73 5% System Samardium-Cobalt, Journal of the Less Common 3,378,671 4/1968 Harrison et al. 75-4755 x Metals, 3, 1968 P- 3,424,578 1/1969 Strnat et a1. 75-213 Prlmary EXamlner 3,546,030 12/ 1970 Buschow et al 148-103 X G. K. WHITE, Assistant Examiner FOREIGN PATENTS US. Cl. X.R.
663,067 12/1951 Great Britain 75-223 75200, 208, 223, 224; 148-101
US32701A 1969-05-14 1970-04-28 Method of manufacturing a permanent magnet Expired - Lifetime US3701695A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6907499A NL6907499A (en) 1969-05-14 1969-05-14

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US (1) US3701695A (en)
AT (1) AT301890B (en)
AU (1) AU1490470A (en)
BE (1) BE750371A (en)
CA (1) CA932247A (en)
CH (1) CH534948A (en)
DE (1) DE2020370A1 (en)
FR (1) FR2047760A5 (en)
GB (1) GB1307296A (en)
NL (1) NL6907499A (en)
SE (1) SE349420B (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855017A (en) * 1971-06-15 1974-12-17 Bbc Brown Boveri & Cie Powderized cobalt rare earth metal compounds and process for making such compounds
US3970484A (en) * 1975-01-20 1976-07-20 Hitachi Magnetics Corporation Sintering methods for cobalt-rare earth alloys
US4210471A (en) * 1976-02-10 1980-07-01 Tdk Electronics, Co., Ltd. Permanent magnet material and process for producing the same
US4213803A (en) * 1976-08-31 1980-07-22 Tdk Electronics Company Limited R2 Co17 Rare type-earth-cobalt, permanent magnet material and process for producing the same
US4776902A (en) * 1984-03-30 1988-10-11 Union Oil Company Of California Method for making rare earth-containing magnets
US4891078A (en) * 1984-03-30 1990-01-02 Union Oil Company Of California Rare earth-containing magnets
US5382303A (en) * 1992-04-13 1995-01-17 Sps Technologies, Inc. Permanent magnets and methods for their fabrication

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3655463A (en) * 1970-04-30 1972-04-11 Gen Electric Sintered cobalt-rare earth intermetallic process using solid sintering additive
DE2215301B2 (en) * 1971-04-06 1976-07-08 N.V. Philips' Gloeilampenfabrieken, Eindhoven (Niederlande) PROCESS FOR MANUFACTURING A BODY WITH ANISOTROPIC PERMANENT MAGNETIC PROPERTIES
CH616777A5 (en) * 1975-09-23 1980-04-15 Bbc Brown Boveri & Cie

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855017A (en) * 1971-06-15 1974-12-17 Bbc Brown Boveri & Cie Powderized cobalt rare earth metal compounds and process for making such compounds
US3970484A (en) * 1975-01-20 1976-07-20 Hitachi Magnetics Corporation Sintering methods for cobalt-rare earth alloys
US4210471A (en) * 1976-02-10 1980-07-01 Tdk Electronics, Co., Ltd. Permanent magnet material and process for producing the same
US4213803A (en) * 1976-08-31 1980-07-22 Tdk Electronics Company Limited R2 Co17 Rare type-earth-cobalt, permanent magnet material and process for producing the same
US4776902A (en) * 1984-03-30 1988-10-11 Union Oil Company Of California Method for making rare earth-containing magnets
US4891078A (en) * 1984-03-30 1990-01-02 Union Oil Company Of California Rare earth-containing magnets
US5382303A (en) * 1992-04-13 1995-01-17 Sps Technologies, Inc. Permanent magnets and methods for their fabrication
US5781843A (en) * 1992-04-13 1998-07-14 The Arnold Engineering Company Permanent magnets and methods for their fabrication

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Publication number Publication date
CA932247A (en) 1973-08-21
DE2020370A1 (en) 1970-11-19
FR2047760A5 (en) 1971-03-12
NL6907499A (en) 1970-11-17
CH534948A (en) 1973-03-15
SE349420B (en) 1972-09-25
BE750371A (en) 1970-11-13
GB1307296A (en) 1973-02-14
AU1490470A (en) 1971-11-18
AT301890B (en) 1972-09-25

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