US3681151A - Method of producing a basic powder for permanent magnets - Google Patents

Method of producing a basic powder for permanent magnets Download PDF

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Publication number
US3681151A
US3681151A US127144A US3681151DA US3681151A US 3681151 A US3681151 A US 3681151A US 127144 A US127144 A US 127144A US 3681151D A US3681151D A US 3681151DA US 3681151 A US3681151 A US 3681151A
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US
United States
Prior art keywords
powder
coercive force
permanent magnets
grinding
basic
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
US127144A
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English (en)
Inventor
Hendrik Cornelis Donkersloot
Johannes Hendrikus Nicol Vucht
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US Philips Corp
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US Philips Corp
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Publication date
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/07—Alloys based on nickel or cobalt based on cobalt
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • 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
    • H01F1/0553—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 obtained by reduction or by hydrogen decrepitation or embrittlement
    • 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
    • H01F1/06—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 in the form of particles, e.g. powder

Definitions

  • the permanent magnets manufactured by means of this basic powder are superior to those obtainable by the known grinding methods with respect to the combination of (BH),,,,, and H
  • the invention relates to a method of manufacturing a basic powder forming the building stone for permanentmagnetisable bodies essential for the permanent-magnetic properties, said bodies consisting of a compound having a hexagonal crystal structure and having a range of existence 'which is integral with that of the compound M R in the M-R-system, wherein M represents Co or a combination of Co with one or more of the elements Fe, Ni and Cu and R represents one or more of the elements of the rare earths and/or Th, said powder being obtained by pulverizing castings of the compound.
  • the elements of the rare earths are considered herein to include also the element Y.
  • the basic powder to be manufactured has to satisfy inter alia the requirement that both the coercive force H and the orientability in a magnetic field should be optimal.
  • a measure for this orientability and moreover, for the squareness of the magnetic hysterisis loop, is the ratio a /tr wherein a, is the saturation magnetisation and a, the remanent magnetisation.
  • the castings are first crushed, for example, into particles having a maximum diameter of 300 nn, which particles are subsequently pulverized in accordance with the invention.
  • H is the coercive force measured on powder ground in argon
  • H is the coercive force measured on powder ground by the method in accordance with the invention.
  • the 0 /1 curve is found to coincide substantially with that measured on powder ground in an inert atmosphere, the first powder being ground in hydrogen.
  • the following table indicates the eifect of the method in accordance with the invention on the magnitude of the coercive force and the orientability of the powder; the values of the coercive force and the orientability are measured on powders pulversized in an argon atmosphere at different hydrogen gas pressures P
  • the basic material was invariably a sieved fraction of crushed castings of the composition concerned, the diameter of the particles being at the most 300 pm. Pulverization was carried out in a vibration apparatus in which the grits were subjected to vibrations for 30 minutes.
  • Ce(MM) represents Ce-rich mixed metal (Mischmetall) of the following composition: 90% by weight of Ce, 7% by weight of La, remainder further elements of the rare earths.
  • the graph of FIG. 4 illustrates the er /d as a function of the hydrogen gas pressure.
  • a melt of the compound obtained in known manner by an arc was crushed in a steel impact morsar.
  • a fraction of a diameter of less than 300 ,um. was sieved from the grits and transferred to a grinding tub of hardened stamp steel; total weight of the powder about 2 g.
  • the grinding tub had a capacity of about cm. and contained 250 steel balls (diameter 3 mm.).
  • the tub was closed hermetically as well as the supply ducts between the interior of the tub and an argon or hydrogen gas cylinder respectively were exhausted vacuum (10- mm. Hg). By means of a regulating cock with a reducing valve the pressure in the tub could be adjusted and be kept constant during the vibration process.
  • the grinding tub was then transferred to a vibration apparatus and subjected to about 1400 vibrations a minute for 30 minutes. After this vibration process the average granular size was found to be less than 1 am.
  • the hydrogen gas employed contained less than 10 p.p.m. of oxygen and/or water vapour.
  • the invention also relates to basic powders for the manufacture of permanent magnets by means of the method in accordance with the invention and to permanentmagnetisable bodies, magnetized or non-magnetized and composed from fine particles whose constituent essential for the permanent-magnetic properties is formed by such a basic powder.
  • the permanent-magnetisable bodies may be formed from compressed powder or sintered powder.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Powder Metallurgy (AREA)
US127144A 1970-04-18 1971-03-23 Method of producing a basic powder for permanent magnets Expired - Lifetime US3681151A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7005646A NL7005646A (xx) 1970-04-18 1970-04-18

Publications (1)

Publication Number Publication Date
US3681151A true US3681151A (en) 1972-08-01

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ID=19809884

Family Applications (1)

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US127144A Expired - Lifetime US3681151A (en) 1970-04-18 1971-03-23 Method of producing a basic powder for permanent magnets

Country Status (9)

Country Link
US (1) US3681151A (xx)
JP (1) JPS5021313B1 (xx)
AU (1) AU2754771A (xx)
BE (1) BE765905A (xx)
BR (1) BR7102237D0 (xx)
CH (1) CH560955A5 (xx)
FR (1) FR2089761A5 (xx)
GB (1) GB1313272A (xx)
NL (1) NL7005646A (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970484A (en) * 1975-01-20 1976-07-20 Hitachi Magnetics Corporation Sintering methods for cobalt-rare earth alloys
US3970485A (en) * 1975-01-20 1976-07-20 Hitachi Magnetics Corporation Binder and lubricant removal from cobalt-rare earth alloys

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1554384A (en) * 1977-04-15 1979-10-17 Magnetic Polymers Ltd Rare earth metal alloy magnets
DE19751367C2 (de) * 1997-11-20 2002-06-27 Dresden Ev Inst Festkoerper Verfahren zur Herstellung eines hartmagnetischen, aus einer Samarium-Kobalt-Basis-Legierung bestehenden Pulvers
DE19751366C2 (de) * 1997-11-20 2002-05-16 Dresden Ev Inst Festkoerper Verfahren zur Herstellung eines hartmagnetischen Samarium-Kobalt-Basis-Materials

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970484A (en) * 1975-01-20 1976-07-20 Hitachi Magnetics Corporation Sintering methods for cobalt-rare earth alloys
US3970485A (en) * 1975-01-20 1976-07-20 Hitachi Magnetics Corporation Binder and lubricant removal from cobalt-rare earth alloys

Also Published As

Publication number Publication date
DE2113932B2 (de) 1976-03-18
CH560955A5 (xx) 1975-04-15
FR2089761A5 (xx) 1972-01-07
AU2754771A (en) 1972-10-19
GB1313272A (en) 1973-04-11
NL7005646A (xx) 1971-10-20
JPS5021313B1 (xx) 1975-07-22
DE2113932A1 (de) 1971-11-11
BR7102237D0 (pt) 1973-04-19
BE765905A (fr) 1971-10-18

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