US3816189A - Solid-state diffusion process for the manufacture of permanent magnet alloys of transition elements and metals of the rare-earth group - Google Patents

Solid-state diffusion process for the manufacture of permanent magnet alloys of transition elements and metals of the rare-earth group Download PDF

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Publication number
US3816189A
US3816189A US00206732A US20673271A US3816189A US 3816189 A US3816189 A US 3816189A US 00206732 A US00206732 A US 00206732A US 20673271 A US20673271 A US 20673271A US 3816189 A US3816189 A US 3816189A
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United States
Prior art keywords
samarium
solid
crucible
alloy
cobalt
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Expired - Lifetime
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US00206732A
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English (en)
Inventor
J Haberer
R Fontaine
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SERMAG
SOC ETUDES ET DE RECHERCHES MAGNETIQUES FR
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SERMAG
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/04—Influencing the temperature of the metal, e.g. by heating or cooling the mould
    • B22D27/045—Directionally solidified castings
    • 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
    • C22C1/02—Making non-ferrous alloys by melting

Definitions

  • ABSTRACT This process is of special interest in the manufacture of a cobalt-Samarium alloy. The attack of the crucible by the samarium is avoided, and the loss of Samarium through evaporation is reduced.
  • the present invention relates to the manufacture of permanent magnet materials based on alloys of transition elements (generally cobalt, possibly with additions of iron and/or copper and/or nickel) and metals of the group comprising the rare-earth metals and yttrium and scandium.
  • This manufacture comprises the preparation, by an alloying operation followed by grinding, of a powder having the required composition, and the consolidation of this powder for forming a magnet, consolidation being carried out, for example, by compression followed by sintering.
  • the present invention concerns the alloying operation. Fusion of the alloy components is mostly carried out in an arc furnace of the button type, in a protective atmosphere of inert gas or in a vacuum, or again by induction in a'refractory crucible of pure alumina,
  • the button furnace has more particularly the following disadvantages: the charge of each button is too small; homogeneity of the alloy is too uncertain; risk of projections involving loss of constituent elements of the alloy; risk of local overheating resulting in nonreproducible evaporation; no possibility of quenching.
  • the invention proposes to remedy these disadvantages. It relates more particularly to the process of induction melting in a refractory crucible. This process is particularly simple to carry out, but in the prior art it has the disadvantage of necessitating the use of a high quality, and therefore expensive, crucible. Indeed, the rare-earth metals forming part of the composition of the alloy and in particular the samarium, are generally strongly reducing with respect to the crucible material, which they destroy relatively rapidly.
  • the present invention proposes to eliminate this disadvantage by carrying out melting of the transition element or elements in a first stage. then after allowing the said element or elements to cool to the commencement of solidification, in, a second stage, of the addition of the rare earth metal or metals by direct diffusion in the transition element or alloy of transition elements in the solid state.
  • the alloy in the case where the alloy is intended to be magnetically hardened in the solid state by precipitation of a weakly magnetic second phase (rich in copper for example) in the grains of a strongly magnetic matrix (rich in cobalt), the solidification of its constituents after casting takes place in an enclosure comprising relatively very hot walls and a relatively cold bottom.
  • a weakly magnetic second phase rich in copper for example
  • a strongly magnetic matrix rich in cobalt
  • F IG. 1 represents a simple device for carrying out the process according to the invention, used by way of example in the case of a cobalt-samarium alloy containing a certain proportion of copper and iron, and
  • FIG. 2 represents in longitudinal section a modification used, for example, in the preparation of a material not comprising a weakly magnetic second phase.
  • FIG. 1 shows, arranged in the interior of an enclosure 1 containing argon at a pressure of 400 torr., a crucible 2 of recrystalized alumina and an ingot mould 3.
  • the enclosure is provided with an opening 4 through which is introduced a samarium rod 5 suspended from a wire 6 provided with a handle 7.
  • the crucible 2 is surrounded by a heating coil 8, through which it is possible to send a high-frequency current.
  • the ingot mould 3 is surrounded by a heating coil 3a. Furthermore, its base 3b is cooled by any means, not shown. For example, it is sufficient if it is made of a plate of a metal which is a good conductor of heat, such as iron.
  • the sides of the ingot mould may be made of a sand containing an inflammable mixture. They could be ignited before casting, or again they could be left to ignite spontaneously during casting of the alloy (exothermic" mould, known per se).
  • the alloy I is reheated slightly to liquefy it, then the crucible is tilted, as indicatedin dashed lines, pouring its contents into the ingot mould.
  • the alloy solidifies with columnar crystallization due to presence of the hot walls and a cold bottom forming a thermal gradient mould.
  • FIG. 2 shows an apparatus serving for example, for the preparation of an alloy on a samarium and cobalt base.
  • This apparatus comprises an alumina crucible 9 surrounded by a high-frequency heating coil 9a, an ingot mould l0 and a samarium magazine ll.
  • a heat-insulating enclosure 12 Arranged between the crucible 9 and coil 9a is a heat-insulating enclosure 12 having in its upper part a circular half-cover provided with an orifice (not shown) and, in its lower part a bottom provided with an 3 orifice 12a situated opposite an orifice 9b of the crucible.
  • the orifice 9b is normally closed by an alumina rod 13 movable in translation and rotation.
  • the magazine 11 is secured to this rod at 11a and 11b. It is formed of a quartz tube, the lower end of which rests on the halfcover 120. In the normal position of the rod, the lower end of the tube 11 is not opposite the orifice, with which the half-cover is provided, so that the samarium remains in the magazine.
  • the rod may be rotated until the tube 11 communicates with the crucible by means of the said orifice; the samarium then descends into the crucible by gravity.
  • the enclosure 12 rests on a brick support 14 pro- .vided at its centre with an orifice opposite the receptacle of the ingot mould.
  • the latter is cooled by circulation of water in a pipe line a, I
  • the cobalt is introduced first into the crucible and its melting is carried out by passing current through the coil.
  • the alloy thus obtained is cooled to l-lOOC, and the rod 13 is manipulated by rotation to produce the introduction of the samarium into the crucible.
  • the slow diffusion of the samarium results in the formation of the complete alloy which is to be obtained.
  • the rod 13 is then moved in translation to release the orifice 9b and permit the alloy to flow into the ingot mould.
  • the apparatus of FIG. 2 could be adapted for columnar crystallization.
  • the ingot mould it would merely be necessary for the ingot mould to be cooled only at the bottom, and for the coil 9a to be lowered at the moment of pouring so as to surround the side wall of the ingot mould and heat the said wall.
  • the apparatus of FIG. 1 could be used for preparing an alloy not comprising a second, weakly magnetic phase.
  • the ingot mould would then have to be cooled througout its entire mass, and would be for example similar to that ofthe apparatus of FIG. 2.
  • An improved process for manufacturing a permanent magnet-type alloy composed of cobalt or an alloy thereof and samarium in a refractory crucible without substantial reaction with and degradation of said crucible said process characterized by forming said alloy in the solid state and below the melting point thereof and comprising the steps of:
  • step (d) heating the solid permanent magnet-type alloy of step (d) to a temperature of about 1350 C. to form a melt, and thereafter,

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Power Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
US00206732A 1970-12-10 1971-12-10 Solid-state diffusion process for the manufacture of permanent magnet alloys of transition elements and metals of the rare-earth group Expired - Lifetime US3816189A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7044447A FR2116861A5 (fr) 1970-12-10 1970-12-10 Procede et dispositif de fabrication d'alliages d'elements de transition et de metaux du groupe des terres rares destinees a la production de materiaux pour aimants permanents

Publications (1)

Publication Number Publication Date
US3816189A true US3816189A (en) 1974-06-11

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US00206732A Expired - Lifetime US3816189A (en) 1970-12-10 1971-12-10 Solid-state diffusion process for the manufacture of permanent magnet alloys of transition elements and metals of the rare-earth group

Country Status (7)

Country Link
US (1) US3816189A (fr)
CH (1) CH545346A (fr)
DE (1) DE2161461C3 (fr)
FR (1) FR2116861A5 (fr)
GB (1) GB1350416A (fr)
IT (1) IT954195B (fr)
NL (1) NL174270C (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4536233A (en) * 1980-12-16 1985-08-20 Kabushiki Kaisha Suwa Seikosha Columnar crystal permanent magnet and method of preparation
AU567701B2 (en) * 1982-10-29 1987-12-03 Wahlbeck, H.G.E. Method and apparatus for the manufacture of non-allergy creating precious metal objects.
EP0756911A3 (fr) * 1995-08-02 1997-05-21 Ald Vacuum Techn Gmbh Procédé et appareil pour la fabrication de particules de pièces coulées et solidifiées directionnellement

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH601481A5 (fr) * 1975-05-05 1978-07-14 Far Fab Assortiments Reunies
DE2658504C2 (de) * 1976-12-23 1986-04-30 Vacuumschmelze Gmbh, 6450 Hanau Verfahren zum Herstellen einer Legierung

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2842439A (en) * 1954-10-01 1958-07-08 Gen Electric High strength alloy for use at elevated temperatures
US3072476A (en) * 1955-03-22 1963-01-08 American Metallurg Products Co Method of alloying
US3194656A (en) * 1961-08-10 1965-07-13 Crucible Steel Co America Method of making composite articles
CA751294A (en) * 1967-01-24 S. Bergh Sven Method for producing ingots
US3421889A (en) * 1966-01-13 1969-01-14 Us Air Force Magnetic rare earth-cobalt alloys
US3544312A (en) * 1968-05-16 1970-12-01 Int Nickel Co Alloying method
US3560200A (en) * 1968-04-01 1971-02-02 Bell Telephone Labor Inc Permanent magnetic materials
US3625779A (en) * 1969-08-21 1971-12-07 Gen Electric Reduction-fusion process for the production of rare earth intermetallic compounds
US3655463A (en) * 1970-04-30 1972-04-11 Gen Electric Sintered cobalt-rare earth intermetallic process using solid sintering additive

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA751294A (en) * 1967-01-24 S. Bergh Sven Method for producing ingots
US2842439A (en) * 1954-10-01 1958-07-08 Gen Electric High strength alloy for use at elevated temperatures
US3072476A (en) * 1955-03-22 1963-01-08 American Metallurg Products Co Method of alloying
US3194656A (en) * 1961-08-10 1965-07-13 Crucible Steel Co America Method of making composite articles
US3421889A (en) * 1966-01-13 1969-01-14 Us Air Force Magnetic rare earth-cobalt alloys
US3560200A (en) * 1968-04-01 1971-02-02 Bell Telephone Labor Inc Permanent magnetic materials
US3544312A (en) * 1968-05-16 1970-12-01 Int Nickel Co Alloying method
US3625779A (en) * 1969-08-21 1971-12-07 Gen Electric Reduction-fusion process for the production of rare earth intermetallic compounds
US3655463A (en) * 1970-04-30 1972-04-11 Gen Electric Sintered cobalt-rare earth intermetallic process using solid sintering additive

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Nassau, K. et al., Intermetallic Compounds Between Lanthanons and Transition Metals, J. Phys. Chem. Soc., 1960, (16) pp. 123 130. *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4536233A (en) * 1980-12-16 1985-08-20 Kabushiki Kaisha Suwa Seikosha Columnar crystal permanent magnet and method of preparation
AU567701B2 (en) * 1982-10-29 1987-12-03 Wahlbeck, H.G.E. Method and apparatus for the manufacture of non-allergy creating precious metal objects.
EP0756911A3 (fr) * 1995-08-02 1997-05-21 Ald Vacuum Techn Gmbh Procédé et appareil pour la fabrication de particules de pièces coulées et solidifiées directionnellement
US5826322A (en) * 1995-08-02 1998-10-27 Ald Vacuum Technologies Gmbh Process and apparatus for the production of particles from castings which have solidified in an oriented manner

Also Published As

Publication number Publication date
GB1350416A (en) 1974-04-18
CH545346A (fr) 1973-12-15
FR2116861A5 (fr) 1972-07-21
NL174270C (nl) 1984-05-16
IT954195B (it) 1973-08-30
DE2161461C3 (de) 1975-06-19
NL174270B (nl) 1983-12-16
NL7116962A (fr) 1972-06-13
DE2161461A1 (de) 1972-06-29
DE2161461B2 (de) 1974-10-31

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