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Publication numberUS3546030 A
Publication typeGrant
Publication dateDec 8, 1970
Filing dateJun 7, 1967
Priority dateJun 16, 1966
Also published asDE1558550A1, DE1558550B2
Publication numberUS 3546030 A, US 3546030A, US-A-3546030, US3546030 A, US3546030A
InventorsKurt Heinz Jurgen Buschow, Wilhelmus Antonius Johan Velge
Original AssigneePhilips Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Permanent magnets built up of m5r
US 3546030 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent Ofi ice 3,546,030 Patented Dec. 8, 1970 3,546,030 PERMANENT MAGNETS BUILT UP F M R Kurt Heinz Jurgen Buschow and Wilhelmus Antonius Johannes Josephus Velge, Emmasingel, Eindhoven,

Netherlands, assignors, by mesne assignments, to U.S. Philips Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed June 7, 1967, Ser. No. 644,101 Claims priority, application Netherlands, June 16, 1966, 6608335 Int. Cl. H01f 1/08; C22c 19/00, 31/02 U.S. Cl. 148--31.57 5 Claims ABSTRACT OF THE DISCLOSURE This invention relates to permanent magnets constituted of fine particles having in themselves permanent magnetic properties. The component of these particles which is essential to these properties is M R, Where M is either Co or a combination of Co with one or more of the elements Fe, Cu, Ni and where R is either La, Th, or a combination of Th with one or more of the elements of the rare earths, or a combination of at least three elements of the rare earths.

Others have measured the magnetic properties of numerous intermetallic compounds of the stoichiometric composition M R. Thus for example, many compounds of the from Co -Z have been examined, where Z is an element of the rare earths which are regarded also to include Y. Of these compounds, the magnetic moments and the temperature dependence of the saturation moments have been measured. Further, the magnetic properties of the compounds Co CnTb, Co NiDy, CdYCo and GdNdCo were determined. All these compounds have a hexagonal structure of the CaCu type.

The present invention is based upon the discovery that in compounds Co R having a similar structure to that of Co Y, the said combination of magnetic properties which causes the compound to be a good raw material for the manufacture of permanent magnets (high uniaxial aniso tropy combined with high saturation magnetization) is obtainable if two conditions are fulfilled With regard to the electron structure of the relevant compound.

First the geometry of the electrons in the Co-ions as compared with that in the compound Co Y must not be essentially changed by R, that is to say the population of the 3-d shell in the Co-ion remain substantially the same.

Secondly, the total magnetic moment of the compound which is built up of contributions of both Co and R must not be detnmentally affected by the contribution of R.

The first condition is generally fulfilled by choosing for R those elements which can form with Co compounds of the relevant structure and which occur as trivalent ions in these compounds. Furthermore Th, Ce and Yb, as well as certain combinations of elements, appear to satisfy the first condition.

The second condition is fulfilled by choosing for R those elements or combinations of elements the total magnetic moments of which are directed in parallel with those of the Co-ions or which do not contribute to the magnetic moment.

When the two conditions are combined there appears to exist for R, in addition to the known elements and combinations of elements, a large number of substitution possibilities. Experiments have shown that of these manifold suitable substitutions for R, only the following elements and combinations of elements with Co can form a compound Co R which can be used with good result (sufliciently high H and (BH) as a raw material for the manufacture of permanent magnets: La, Th, or a combination of Th with one or more of the elements of the rare earths, or combinations of at least three rare earths.

It is possible in these compounds to choose for M, instead of the above-mentioned Co, a combination of Co with one or more of the elements Fe, Ni, Cu. The compounds in which M is such a combination generally have a lower sensitivity to deformation of the coercive force and the saturation magnetization.

The extent to which Fe, or Ni, Co or a combination can be substituted for M while retaining favorable magnetic properties depends upon R and the substituents which have been chosen. Thus it has been found, for example, that if R is La and M is a combination of Co and Fe, no more than 5 at. precent of Fe may be present, Whereas the maximum content of Fe may be at. percent if R is Th. If the Fe-content exceeds the specified percentages, the examples given no longer have the hexagonal structure required, resulting in an abrupt decline in magnetic properties. However, in other examples, the magnetic properties may decline gradually, starting from a certain atomic percentage of the substituent.

The compounds Co La, Co La Sm Th and C0 La Ce Sm for example, satisfy the abovementioned conditions.

The invention also relates to a method of manufacturing a permanent magnet as above described. In this method, a body is first manufactured by melting the component elements to form the compound of R and subsequently cooling the mass. The body is homogenized by annealing in an atmosphere which protects against oxidizing influences, at a temperature which lies as nearly as possible, i.e., immediately, below the melting point. The body is subsequently cooled to room temperature and pulverized. The powder, possibly after annealing, then is formed into a magnetic body by molding, possibly in a magnetic field.

Compounds of the formula M R generally have an incongment melting point. As a result, compounds of R and M other than M R may also occur during solidification. During the annealing of the molding at a temperature which lies just below the melting temperature, all the compounds formed during solidification will be converted into the compound M R, that is to say are homogenized. The temperature is chosen therefore at a maximum inter alia to give the particles the greater possible mobility, which enhances an efficient conversion of other compounds into M R.

The homogenization is followed by cooling to room temperature. This cooling may take place at a low rate if no undesired phases occur during this process. If, however, this should be the case, then in one form of the method according to the invention the body should be quenched to room temperature after homogenization.

The quenching process affords the additional advantage that the body becomes more brittle and this is advantageous with a view to the subsequent pulverization.

The invention may be explained more fully with reference to magnetic properties measured on the following examples of compounds (M R particles) according to the invention all which were made in the aforesaid manner:

The maximum energy product (BH) has been measured on a permanent magnet made from CO La Ce Sm and is 5x10 GausS-OerSted.

What is claimed is:

1. A permanent magnet constituted of fine particles, and having magnetic properties, said particles having as a component which is essential to these properties the compound M R, having a hexagonal crystal structure where M is selected from the group consisting of Co and a combination of Co with at least one element selected from the group consisting of Fe, Cu, Ni and where R is selected from the group consisting of La, Th a combination of about 50% La, about 25% Ce and about 25% Sin, and a combination of Th with up to two of the rare earth elements.

2. A permanent magnet as claimed in claim 1 in which R is a combination of Th and two rare earth elements.

3. A permanent magnet as claimed in claim 1 in which M is Co and R is La.

4. A permanent magnet as claimed in claim 2 in which M is Co and R is La Sm Th 5. A permanent magnet as claimed in claim 1 in which M is Co and R is La Ce Sm References Cited UNITED STATES PATENTS 2,813,789 11/1957 Glaser 123 3,102,0U2 871963 WalIaceet al. 'L. 75 1'52X 3,326,637 6/1967 Holtzberg et al. 75152X 3,342,591 9/1967 Gambino et al. 75152 3,421,889 1/1969 Ostertag et a1 75170 3,424,578 1/1969 Strnat et al. 75213 L. DEWAYNE RUTLEDGE, Primary Examiner G. K. WHITE, Assistant Examiner U.S. Cl. X.R.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2813789 *Apr 8, 1952Nov 19, 1957Glaser LouisPermanent magnet alloys
US3102002 *Mar 25, 1960Aug 27, 1963Univ PittsburghFerromagnetic materials prepared from lanthanons and transition metals
US3326637 *Dec 27, 1963Jun 20, 1967IbmFerromagnetic intermetallic compounds and method of preparation
US3342591 *Aug 31, 1964Sep 19, 1967IbmFerromagnetic compounds and method of preparation
US3421889 *Jan 13, 1966Jan 14, 1969Us Air ForceMagnetic rare earth-cobalt alloys
US3424578 *Jun 5, 1967Jan 28, 1969Us Air ForceMethod of producing permanent magnets of rare earth metals containing co,or mixtures of co,fe and mn
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3652343 *Sep 14, 1970Mar 28, 1972Gen ElectricPermanent magnet material powders having superior magnetic characteristics
US3655463 *Apr 30, 1970Apr 11, 1972Gen ElectricSintered cobalt-rare earth intermetallic process using solid sintering additive
US3655464 *Apr 30, 1970Apr 11, 1972Gen ElectricProcess of preparing a liquid sintered cobalt-rare earth intermetallic product
US3664892 *Sep 17, 1970May 23, 1972Gen ElectricPermanent magnet material powders having superior magnetic characteristics
US3755007 *Apr 1, 1971Aug 28, 1973Gen ElectricStabilized permanent magnet comprising a sintered and quenched body of compacted cobalt-rare earth particles
US3790414 *Nov 14, 1968Feb 5, 1974Matsushita Electric Ind Co LtdAs-CAST, RARE-EARTH-Co-Cu PERMANENT MAGNET MATERIAL
US3839102 *Nov 10, 1970Oct 1, 1974Matsushita Electric Ind Co LtdPermanent magnet
US3844850 *Apr 17, 1972Oct 29, 1974Gen ElectricLarge grain cobalt-samarium intermetallic permanent magnet material and process
US3856579 *Dec 4, 1972Dec 24, 1974Battelle Development CorpSputtered magnetic materials comprising rare-earth metals and method of preparation
US3905839 *Feb 26, 1974Sep 16, 1975Gen ElectricLiquid sintered cobalt-rare earth intermetallic product
US3905840 *Sep 18, 1974Sep 16, 1975Gen ElectricSintered cobalt-rare earth intermetallic product
US3919002 *Feb 11, 1974Nov 11, 1975Gen ElectricSintered cobalt-rare earth intermetallic product
US3919003 *Feb 11, 1974Nov 11, 1975Gen ElectricSintered cobalt-rare earth intermetallic product
US3919004 *Feb 15, 1974Nov 11, 1975Gen ElectricLiquid sintered cobalt-rare earth intermetallic product
US3947295 *Feb 7, 1974Mar 30, 1976Matsushita Electric Industrial Co., Ltd.Hard magnetic material
US3956031 *Dec 24, 1969May 11, 1976Texas Instruments IncorporatedMagnetic materials and the formation thereof
US3997371 *Nov 4, 1974Dec 14, 1976Hitachi Metals, Ltd.Permanent magnet
US4002508 *Aug 14, 1975Jan 11, 1977Aimants Ugimag S.A.Composition for permanent magnets of the family "rare earths-transition metals" and process for producing such a magnet
US4003767 *Apr 7, 1975Jan 18, 1977Bbc Brown Boveri & Company LimitedProcedure for the production of permanent magnetic sinter bodies using a ternary cobalt-lanthanoid compound
US4075042 *May 9, 1977Feb 21, 1978Raytheon CompanySintering, intermetallic
US4210471 *Feb 8, 1977Jul 1, 1980Tdk Electronics, Co., Ltd.Permanent magnet material and process for producing the same
US4213803 *Feb 8, 1977Jul 22, 1980Tdk Electronics Company LimitedR2 Co17 Rare type-earth-cobalt, permanent magnet material and process for producing the same
US4370295 *Jun 9, 1980Jan 25, 1983Fdx Associates, L.P.Fusion-fission power generating device having fissile-fertile material within the region of the toroidal field coils generating means
US4370296 *Jun 9, 1980Jan 25, 1983Fdx Associates, L.P.And method of increasing efficiency
US4378331 *Jul 28, 1980Mar 29, 1983U.S. Philips CorporationHydrides of the formula AD N HM
US4382061 *Aug 5, 1981May 3, 1983Th. Goldschmidt AgAlloy preparation for permanent magnets
US4536233 *Nov 30, 1983Aug 20, 1985Kabushiki Kaisha Suwa SeikoshaColumnar crystal permanent magnet and method of preparation
US4710242 *Jun 3, 1986Dec 1, 1987Fujitsu LimitedMaterial for temperature sensitive elements
US5382303 *Apr 13, 1992Jan 17, 1995Sps Technologies, Inc.Permanent magnets and methods for their fabrication
US5781843 *Oct 20, 1994Jul 14, 1998The Arnold Engineering CompanyPermanent magnets and methods for their fabrication
DE2003749A1 *Jan 22, 1970Jul 30, 1970Philips NvHydride mit der Formel ABnHm
Classifications
U.S. Classification420/435, 148/303, 148/401, 148/313, 420/581, 148/301, 148/103
International ClassificationC22C9/00, C22C28/00, H01F1/055, C22C19/00
Cooperative ClassificationC22C19/00, C22C9/00, C22C28/00, H01F1/0557
European ClassificationC22C9/00, C22C19/00, H01F1/055D4, C22C28/00