US3855017A - Powderized cobalt rare earth metal compounds and process for making such compounds - Google Patents

Powderized cobalt rare earth metal compounds and process for making such compounds Download PDF

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Publication number
US3855017A
US3855017A US00249538A US24953872A US3855017A US 3855017 A US3855017 A US 3855017A US 00249538 A US00249538 A US 00249538A US 24953872 A US24953872 A US 24953872A US 3855017 A US3855017 A US 3855017A
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reaction
cobalt
samarium
reaction vessel
compounds
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US00249538A
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English (en)
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C Schueler
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BBC Brown Boveri AG Switzerland
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Bbc Brown Boveri & Cie
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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
    • H01F1/06—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
    • 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

Definitions

  • the invention relates to a process for the preparation of pulverulent or powderized compounds of cobalt and any rare earth metal or mixtures of such rare earth metals, whereby a gas transport reaction is employed.
  • the present powderized compounds are especially useful for making hard magnets.
  • Pulverulent compounds made of cobalt and rare earth metals or mixtures thereof have achieved great importance for the production of permanent magnets, because they have a very high coercive force (see, for example, Scientific American", December 1970, pages 92 et seq or Physik In Republicer Zeit, 1970, No. 4, pages 103 et seq).
  • the compound is first produced by metallurgical melting processes and then the resulting product is ground.
  • the powder is then usually screened, brought into an aligning magnetic field, pressed into a blank and finally sintered.
  • reaction components are kept in motion and simultaneously subjected to the action of grinding weights.
  • the gas transport reaction may take place in such a manner that the reaction components are heated in a closed reaction system or space into which the reaction components have been introduced in their solid state form in the presence of a transport substance, especially iodine.
  • the reaction components and the transport substance form compounds which are volatile at the reaction temperature whereby the equilibrium constant of the reaction system is such that a reaction between the volatile cobalt compound and a rare earth metal is possible whereby cobalt is released and that further a reaction is possible between the volatile rare earth metal compound and cobalt whereby the rare earth metal is released.
  • the gas transport reaction may also be accomplished according to a modified embodiment wherein the cobalt in powder form and the rare earth metal or mixtures of rare earth metals in any suitable form, for example in coarsely comminuted form, are heated in a common reaction chamber to a temperature at which the rare earth metal or the rare earth metal mixtures evaporate to a substantial extent and at which temperature the cobalt vaporizes merely insignificantly.
  • FIG. 1 shows an apparatus for performing the process according to the invention, in which a special transport substance is provided
  • FIG. 2 is an apparatus for performing the process according to the invention without a special transport substance.
  • an inert gas may be provided in the reaction chamber 6, which is small in order to reduce the transport distances.
  • the temperature reaction parameter can be varied locally and/or as a function of time within the thermodynamic limits determined by the end product.
  • Example 2 This relates to the production of high-coercivity Co Sm by gas transport reaction without the use of a special transport substance.
  • the ampoule 5 was then secured to the device 7 whereby the ampoule can be rotated about the longitudinal axis.
  • the ampoule and its rotating device were placed into an oven (not shown).
  • the oven was heated to 750 I,150C, e.g., 850C, and the quartz ampoule 5 together with the reaction vessel 3 and contents was left therein for a period ranging from a few hours to several days, for example 24 hours.
  • the ampoule was rotated at about 10-500, e.g., r.p.m. As in example I, here again the temperature limits are not critical.
  • the reaction chamber 6 is divided into two chambers by a partition 8 having an opening 9.
  • the samarium shavings 2 are disposed in one chamber and the cobalt powder 1 and grinding weights 4 in the other chamber.
  • Reaction components 1, 2 and the grinding weights 4 may alternatively be used as shown in FIG. 1 in a mixture with one another and located in a reaction chamber without a partition.
  • the samarium difuses as a vapor through the opening 9 in the apparatus shown in FIG. 2 to the cobalt powder 1 where it reacts with the cobalt.
  • Cobalt has a vapor pressure of about 10 Torr at a temperature of 850C, while samarium has a vapor pressure of about 2 X 10' Torr at the same temperature. There is therefore migration of practically only the samarium.
  • the reaction is complete after a period ranging from a few hours to several days, depending upon the temperature. For example, completion after 24 hours is accomplished at 850C, whereby Co Sm is obtained in powder form which is removed from the vessel after cooling.
  • the shape and particle size of the finished product are dependent upon the following parameters: the reaction temperature, reaction time, size and shape of the molybdenum grinding pieces, and the ratio of the weight of the charge (Sm+5Co) to the total weight of molybdenum pieces.
  • a desired particle size and particle shape for the reaction product can be obtained by suitable selection of the parameters within certain limits.
  • the shape and size of the powder to be produced can also be influenced by different temperatures in the subchambers of the reaction vessel 3. If the temperature in the chamber containing the samarium 2 is too high, a eutectic may form in the Co powder 1, this is undesirable because it has too low a melting point since the samarium vaporizes too rapidly and the supply in the chamber containing the cobalt is correspondingly high. The molten eutectic may then bond the grains so strongly that the molybdenum pieces 6 cannot break open the layer whereby the further reaction is stopped. The lower the temperature in the chamber containing the cobalt powder 1, the slower the diffusion of samarium into the cobalt grains and hence the slower the reaction to the end product.
  • the coercive force of the SmCo can also be influenced or optimized by suitable selection of the temperatures in the two chambers.
  • nX m2 X Z for example 1 Sm +5 Co SmCo has a much higher vapor pressure than the other component, i.e., Z or C0, and if the intermediate phases e.g., Sm Co and the like, have melting points higher than the lowest reaction temperature still practical in the chamber of the reaction vessel 3 containing the cobalt powder 1 in FIG. 2.
  • the process according to the invention can also be used to great advantage for the preparation of other cobalt and rare earth metal compounds, for example Ce MM Sm C wherein MM denotes the misch metal which is well known in the steel production as a mixture of rare earth metals.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Hard Magnetic Materials (AREA)
US00249538A 1971-06-15 1972-05-02 Powderized cobalt rare earth metal compounds and process for making such compounds Expired - Lifetime US3855017A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH868671A CH577561A5 (enrdf_load_stackoverflow) 1971-06-15 1971-06-15

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US3855017A true US3855017A (en) 1974-12-17

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US (1) US3855017A (enrdf_load_stackoverflow)
AT (1) AT311067B (enrdf_load_stackoverflow)
CA (1) CA970186A (enrdf_load_stackoverflow)
CH (1) CH577561A5 (enrdf_load_stackoverflow)
DE (1) DE2134212B2 (enrdf_load_stackoverflow)
FR (1) FR2142389A5 (enrdf_load_stackoverflow)
GB (1) GB1372287A (enrdf_load_stackoverflow)
IT (1) IT956507B (enrdf_load_stackoverflow)
NL (1) NL7208021A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5045289A (en) * 1989-10-04 1991-09-03 Research Corporation Technologies, Inc. Formation of rare earth carbonates using supercritical carbon dioxide
US20150176119A1 (en) * 2013-12-19 2015-06-25 James M. Blackwell Additives to improve the performance of a precursor source for cobalt deposition

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US64416A (en) * 1867-05-07 James hart
US2592783A (en) * 1946-04-17 1952-04-15 Aspegren Olof Erik August Rotary heat exchanger
US2991176A (en) * 1959-04-15 1961-07-04 L D Caulk Company Method for making dental amalgams and product thereof
US3126346A (en) * 1964-03-24 Ferromagnetic compositions and their preparation
US3424578A (en) * 1967-06-05 1969-01-28 Us Air Force Method of producing permanent magnets of rare earth metals containing co,or mixtures of co,fe and mn
US3578417A (en) * 1969-06-30 1971-05-11 Pan American Sulphur Co Vaporizing sulfur from ore by direct contact with heated pebbles
US3677947A (en) * 1969-09-02 1972-07-18 Goldschmidt Ag Th Permanent magnet
US3701695A (en) * 1969-05-14 1972-10-31 Philips Corp Method of manufacturing a permanent magnet

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US64416A (en) * 1867-05-07 James hart
US3126346A (en) * 1964-03-24 Ferromagnetic compositions and their preparation
US2592783A (en) * 1946-04-17 1952-04-15 Aspegren Olof Erik August Rotary heat exchanger
US2991176A (en) * 1959-04-15 1961-07-04 L D Caulk Company Method for making dental amalgams and product thereof
US3424578A (en) * 1967-06-05 1969-01-28 Us Air Force Method of producing permanent magnets of rare earth metals containing co,or mixtures of co,fe and mn
US3701695A (en) * 1969-05-14 1972-10-31 Philips Corp Method of manufacturing a permanent magnet
US3578417A (en) * 1969-06-30 1971-05-11 Pan American Sulphur Co Vaporizing sulfur from ore by direct contact with heated pebbles
US3677947A (en) * 1969-09-02 1972-07-18 Goldschmidt Ag Th Permanent magnet

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5045289A (en) * 1989-10-04 1991-09-03 Research Corporation Technologies, Inc. Formation of rare earth carbonates using supercritical carbon dioxide
US20150176119A1 (en) * 2013-12-19 2015-06-25 James M. Blackwell Additives to improve the performance of a precursor source for cobalt deposition
US9090964B2 (en) * 2013-12-19 2015-07-28 Intel Corporation Additives to improve the performance of a precursor source for cobalt deposition

Also Published As

Publication number Publication date
DE2134212B2 (de) 1973-08-30
CA970186A (en) 1975-07-01
DE2134212A1 (de) 1973-01-04
FR2142389A5 (enrdf_load_stackoverflow) 1973-01-26
AT311067B (de) 1973-10-25
GB1372287A (en) 1974-10-30
DE2134212C3 (enrdf_load_stackoverflow) 1974-03-28
NL7208021A (enrdf_load_stackoverflow) 1972-12-19
CH577561A5 (enrdf_load_stackoverflow) 1976-07-15
IT956507B (it) 1973-10-10

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