EP0124655B1 - Aimants permanents isotropes et procédé pour leur fabrication - Google Patents

Aimants permanents isotropes et procédé pour leur fabrication Download PDF

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EP0124655B1
EP0124655B1 EP19830113252 EP83113252A EP0124655B1 EP 0124655 B1 EP0124655 B1 EP 0124655B1 EP 19830113252 EP19830113252 EP 19830113252 EP 83113252 A EP83113252 A EP 83113252A EP 0124655 B1 EP0124655 B1 EP 0124655B1
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Prior art keywords
elements
magnet
atomic
added
crystal grain
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German (de)
English (en)
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EP0124655A3 (en
EP0124655A2 (fr
Inventor
Setsuo Hanazonodanchi 14-106 Fujimura
Masato Sagawa
Yutaka Matsuura
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Neomax Co Ltd
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Sumitomo Special Metals Co Ltd
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Priority claimed from JP58079096A external-priority patent/JPS59204209A/ja
Priority claimed from JP58079098A external-priority patent/JPS59204211A/ja
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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
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered

Definitions

  • the present invention relates generally to isotropic permanent magnets and, more particularly, to novel magnets based on FeBR alloys and expressed in terms of FeBR and FeBRM.
  • the term "isotropy” or “isotropic” is used with respect to magnetic properties.
  • R is used as a symbol to indicate rare-earth elements including yttrium Y
  • M is used as a symbol to denote additional elements such as Al, Ti, V, Cr, Mn, Zr, Hf, Nb, Ta, Mo, Ge, Sb, Sn, Bi, Ni and W
  • A is used as a symbol to refer to elements such as copper Cu, phosphorus P, carbon C, sulfur S, calcium Ca, magnesium Mg, oxygen O and silicon Si.
  • Permanent magnets are one of functional materials which is practically indispensable for electronic equipments.
  • the permanent magnets currently in use mainly include Alnico O magnets, ferrite magnets, rare earth-cobalt (RCo) magnets and more.
  • RCo rare earth-cobalt
  • the permanent magnets used therefor are required to possess high properties correspondingly.
  • the isotropic permanent magnets are inferior to the anisotropic magnets in certain points in view of performance, the isotropic magnets find good use due to such magnetic properties that no limitation is imposed upon the shape and the direction of magnetization. However, there is left much to be desired in performance.
  • the anisotropic magnets rather than the isotropic magnets are generally put to practical use due to their usually high performance.
  • the isotropic magnets are substantially formed of the same material as the anistropic magnets, for instance, Alnico O magnets, ferrite magnets, MnAI magnets and FeCrCo magnets show a maximum energy product (BH)max of barely 16 kJ/m 3 (2 MGOe).
  • SmCo magnets broken down into RCo magnets show a relatively high value on the order of 32-40 kJ/m 3 (4-5 MGOe), which is nonetheless only 1/4-1/6 times those of the anistropic magnets.
  • the SmCo magnets still offer some problems in connection with practicality, since they are very expensive because of the fact that samarium Sm which is rare in resources is needed, and that it is required to use a large amount, i.e., 50-60 weight % of cobalt Co, the supply of which is uncertain.
  • amorphous alloys based on (Fe, Ni, Co)-R can be obtained by melt-quenching.
  • This process yields magnets having (BH)max of 32-40 kJ/m 3 (4-5 MGOe).
  • the resulting ribbons have a thickness ranging from several microns to a few tens microns, they should be laminated or compacted after pulverization in order to obtain magnets of practical bulk. With any existing methods, a lowering of density and a further lowering of magnetic properties would take place. After all, it is unfeasible to introduce improvements in magnetic properties.
  • EP-A-101 552 an alloy is disclosed which contains at least one stable compound of the ternary Fe-B-R type having a tetragonal crystal structure and which can be magnetized to become a permanent magnet at room temperature or above.
  • EP-A-126179 a process for producing permanent magnet materials of the Fe-B-R type is disclosed.
  • the process comprises melting and cooling a special composition or reducing a mixture of rare earth oxides and the other metallic materials.
  • the present invention aims at providing isotropic permanent magnets (and materials) having magnetic properties equivalent to, or greater than, those of the conventional products, in which resourceful materials, especially Fe, and resourceful rare-earth elements are mainly used, and in which Sm and the like having problems in resources may not necessarily be used as R.
  • the present invention aims at providing isotropic permanent magnets having improved magnetic properties such as improved coercive force.
  • the present invention aims at providing isotropic permanent magnets which are inexpensive, but are practically of sufficient value.
  • the present invention also aims at providing a process for the production of these magnets.
  • magnetically isotropic sintered permanent magnets based on FeBR type compositions More specifically, according to the first aspect, there is provided an isotropic sintered permanent magnet based on FeBR; according to the second aspect, there is provided an FeBR base magnet, the mean crystal grain size of which is 1-160 pm after sintering; and according to the third aspect, there is provided a process for the production of the FeBR base, isotropic sintered permanent magnets as referred to the first and second aspects.
  • the 4th-6th aspects of the present invention relate to FeBRM type compositions. More specifically, according to the fourth aspect, there is provided an isotropic permanent magnet based on FeBRM; according to the fifth aspect, there is provided a FeBRM base magnet, the mean crystal grain size of which is 1-100 pm after sintering; and according to the sixth aspect, there is provided a process for the production of the magnets as referred to the fourth and fifth aspects.
  • the seventh aspect of the present invention is concerned with an allowable level of impurities, which is applicable to the FeBR and FeBRM systems alike, and offers advantages in view of the practical products and the process of production thereof as well as commercial productivity.
  • % means “atomic %” unless otherwise specified.
  • the isotropic permanent magnets according to the first aspect of the present invention are characterized in that they have a composition (hereinafter referred to "the FeBR composition or system") comprising, in atomic percent, 10-25% of R, 3-23% of boron B and the balance being iron Fe and inevitable impurities, are isotropic, and are obtained as sintered bodies by powder metallurgy.
  • the FeBR composition or system a composition comprising, in atomic percent, 10-25% of R, 3-23% of boron B and the balance being iron Fe and inevitable impurities
  • the isotropic permanet magnets according to the second aspect of the present invention are characterized in that they have the aforesaid FeBR composition, and the sintered bodies have a mean crystal grain size of 1-160 pm after sintering.
  • the present inventors already invented FeBR base, anisotropic permanent magnets in which Sm and Co were not necessarily used.
  • FeBR base, isotropic permanent magnets obtained according to the present invention have properties equivalent to, or greater than, those of the SmCo base, isotropic magnets, and are inexpensive and practically of extremely high value, since expensive Sm may not necessarily be used with no need of using Co.
  • the term "isotropy" used to indicate one of the properties of the permanent magnets means that they are substantially isotropic, i.e., in a sense that no magnetic field is applied during compacting or forming, and also implies isotropy that may appear by compacting or forming.
  • the permanent magnet of the fourth aspect in which the sintered body has a mean crystal grain size ranging from about 1 pm to about 100 pm.
  • the isotropic sintered permanent magnets according to the seventh aspect of the present invention comprises the FeBR and FeBRM compositions in which one or more of A are further contained in given percents.
  • A stands for no more than 3.3% copper Cu, no more than 2.5% sulfur S, no more than 4.0% carbon C, no more than 3.3% phosphorus P, each no more than 4.0% Ca and Mg, no more than 2.0% O and no more than 5.0% Si. It is noted that the combined amount of A is no more than the maximum value among the values specified above of said elements A actually contained, and, when M and A are contained, the sum of M plus A is no more than the maximum value among the values specified above of said elements M and A actually added and contained.
  • the permanent magnets are obtained as magnetically isotropic sintered bodies, a process for the preparation of which is herein disclosed and characterized in that the respective alloy powders of the FeBR and FeBRM compositions are compacted, followed by sintering (the third and sixth aspects). It is noted that the alloy powders are novel and crystalline rather than amorphous.
  • the starting alloys are prepared by melting and cooled. The thus cooled alloys are pulverized, compacted under pressure and sintered resulting in isotropic permanent magnets. Cooling of the molten alloys may usually be done by casting and other cooling manners.
  • FeBR, FeBRA, FeBRM and FeBRMA systems of the present invention are all based on the FeBR system, and are similarly determined in respect of the ranges of B and R.
  • the amount of B should be no less than 3 atomic % (hereinafter "%" stands for the atomic percent in the alloys) in the present invention.
  • % stands for the atomic percent in the alloys
  • An increase in the amount of B increases iHc but decreases Br (see Figs. 2 and 6).
  • the amount of B should be no more than 23% to obtain Br of at least 0.3 T (3 kG) to achieve (BH)max of no less than 16 kJ/m 3 (2 MGOe).
  • Figs. 1 and 5 are illustrative of the relationship between the amount of R and iHc as well as Br in the FeBR and FeBRM systems. As the amount of R increases, iHc increases, but Br increases then decreases depicting peak. Hence, the amount of R should be no less than 10% to obtain (BH)max of no less than 16 kJ/m 3 (2 MGOe), and should be no more than 25% for similar reasons and due to the fact that R is expensive, and so likely to burn that difficulties are involved in technical handling and production.
  • B and R are the FeBR compositions in which R is 12-20% with the main component being light rare earth such as Nd and/or Pr (the light rare earth amounting to 50% or higher of the overall R), B is 5-18% and the balance is Fe, and the FeBRM compositions wherein the aforesaid ranges hold for Fe, B and R, and M is further within a range providing at least 0.4 T (4 kG) Br, since it is then possible to achieve high magnetic properties represented by (BH)max of no less than 32 kJ/m 3 (4MGOe).
  • R is 12-20% with the main component being light rare earth such as Nd and/or Pr (the light rare earth amounting to 50% or higher of the overall R)
  • B is 5-18% and the balance is Fe
  • Fe, B and R are the FeBR compositions in which R is 12-16% with the main component being light rare earth such as Nd or Pr, B is 6-18% and the balance being Fe, and the FeBRM compositions wherein the aforesaid ranges hold for Fe, B and R, and M is within a range providing at least 0.6 T (6 kG) Br, since it is then possible to achieve high properties represented by (BH)max of no less than 56 kJ/m 3 (7 MGOe) which has never been obtained in the conventional isotropic permanent magnets.
  • the present invention is very useful, since the raw materials are inexpensive owing to the fact that resourceful rare earth elements which are resourceful or find no wide use else can be used as R, and that Sm may not necessarily be used, and may not be used as the main ingredient.
  • R used in the permanent magnets of the present invention include light- and heavy-rare earth, and at least one thereof may be used. That is, use may be made of Nd, Pr, lanthanum La, cerium Ce, terbium Te, dysprosium Dy, holmium Ho, erbium Er, europium Eu, samarium Sm, gadolinium Gd, promethium Pm, thulium Tm, ytterbium Yb, lutetium Lu, Y and the like. It suffices to use light rare earth as R, and particular preference is given to Nd and/or Pr, e.g., no less than 50% of R or mainly of R.
  • R usually, it suffices to use one element as R, but, practically, use may be made of mixtures of two or more elements such as mischmetal, dydimium, etc. due to easiness in availability.
  • Sm, La, Ce, Gd, Y, etc. may be used in the form of mixtures with light rare earth such as Nd and/or Pr.
  • R may not be pure light rare-earth elements, and contain inevitable impurities entrained from the process of production (other rare-earth elements, Ca, Mg, Fe, Ti, C, O, etc.), as long as such R is industrially available.
  • the starting B may be pure boron or alloys of B with other constitutional elements such as ferroboron, and may contain as impurities Al, C, silicon Si and more. The same holds for all the aspects of the present invention.
  • the FeBR base permanent magnets disclosed in the prior application are obtained as magnetically anisotropic sintered bodies, and the permanent magnets of the present invention are obtained as similar sintered bodies, except that they are isotropic.
  • the isotropic permanent magnets of the present invention are obtained by preparing alloys, e.g., by melting and cooling and pulverizing, compacting and sintering the alloy compacts.
  • Melting may be carried out in vacuo or in an inert gas atmosphere, and cooling may be effected by, e.g., casting.
  • a mold formed of copper or other metals may be used.
  • a water-cooled type mold is used with the application of a rapid cooling rate to prevent segregation of the ingredients of ingot alloys.
  • the alloys are coarsely ground in a stamp mill or like means and, then, finely pulverized in an attritor, ball mill or like means to no more than about 400 pm preferably 1-100 pm.
  • mechanical pulverization means such as spraying and physicochemical pulverization means such as reducing or electrolytic means may be relied upon for the pulverization of the FeBR base alloys.
  • the alloys of the present invention may be obtained by a so-called direct reduction process in which the oxides of rare earth are directly reduced in the presence of other constitutional elements (e.g., Fe and B or an alloy thereof) with the use of a reducing agent such as Ca, Mg or the like.
  • the finely pulverized alloys are formulated into a given composition.
  • the FeBR base or mother alloys may partly be added with constitutional elements or alloys thereof for the purpose of adjusting the composition.
  • the alloy powders formulated to the given composition are compacted under pressure in the conventional manner, and the resultant compact is sintered at a temperature approximately of 900-1200°C, preferably 1050-1150°C for a given period of time. It is possible to obtain the isotropic sintered magnet bodies having high magnetic properties by selecting the sintering conditions (especially temperature and time) in such a manner that the mean crystal grain size of the sintered bodies comes within the predetermined range after sintering. For instance, sintered bodies having a preferable mean crystal grain size can be obtained by compacting the starting alloy powders having a particle size of no more than 100 pm followed by sintering at 1050-1150°C for 30 minutes to 8 hours.
  • sintering is carried out preferably in vacuo or in an inert gas atmosphere which may be vacuo or reduced pressure, e.g., 1.33 Pa (10 -2 Torr) or less or inert or reducing gas with a purity of 99.9% or higher at 133-101325 Pa (1-760 Torr).
  • inert gas atmosphere which may be vacuo or reduced pressure, e.g., 1.33 Pa (10 -2 Torr) or less or inert or reducing gas with a purity of 99.9% or higher at 133-101325 Pa (1-760 Torr).
  • bonding agents such as camphor, paraffin, resins, ammonium chloride or the like and lubricants or compacting aids such as zinc stearate, calcium stearate, paraffin, resins or the like.
  • Samples of 77Fe-8B-15Nd were prepared by the following steps. In what follows, the unit of purity is weight %.
  • Table 1 The permanent magnet samples shown in Table 1 prepared by the foregoing steps were measured for the magnetic properties iHc, Br and (BH)max thereof. Table 1 shows the magnetic properties of the individual samples at room temperature.
  • the permanent magnets of the FeBR base sintered bodies are the single domain, fine particle type magnets, which give rise to unpreferable magnet properties without being subjected to once pulverization followed by compacting under pressure and sintering.
  • the mean crystal grain size should be within the range of 1-160 pm to achieve iHc of no less than 79.6 kA/m (1 kOe), and within a range of 1-110 ⁇ m to achieve iHc of no less than 159.2 kA/m (2 kOe).
  • a range of 1-80 pm is preferable, and a range of 3-10 pm is most preferable.
  • the magnetic material and permanent magnets based on the Fe-B-R alloy according to the present invention can satisfactorily exhibit their own magnetic properties due to the fact that the major phase is formed by the substantially tetragonal crystals of the Fe-B-R type.
  • the Fe-B-R type alloy is characterized by its high Curie point and it has further been experimentally ascertained that the presence of the substantially tetragonal crystals of the Fe-B-R type contributes to the exhibition of magnetic properties.
  • the contribution of the Fe-B-R base tetragonal system alloy to the magnetic properties is unknown in the art, and serves to provide a vital guiding principle forthe production of magnetic materials and permanent magnets having high magnetic properties as aimed at in the present invention.
  • the tetragonal system of the Fe-B-R type alloys according to the present invention has lattice constants of ao: about 0.88 nm (8.8 A) and Co: about 1.22 nm (12.2 A). It is useful where this tetragonal system compounds constitute the major phase of the Fe-B-R type magnets, i.e., it should occupy 50 vol.% or more of the crystal structure in order to yield practical and good magnetic properties.
  • the presence of a Rare earth (R) rich phase serves to yielding of good magnetic properties, e.g., the presence of 1 vol.% or more of such R-rich phase is very effective.
  • the Fe-B-R tetragonal system compounds are present in a wide compositional range, and may be present in a stable state also upon addition of certain elements other than R, Fe and B.
  • the magnetically effective tetragonal system may be "substantially tetragonal" which term comprises ones that have a slightly deflected angle between a, b and c axes, e.g., within about 1°, or ones that have ao slightly different from bo, e.g., within about 1%.
  • the aforesaid fundamental tetragonal system compounds are stable and provide good permanent magnets, even when they contain up to 1 % of H, Li, Na, K, Be, Sr, Ba, Ag, Zn, N, F, Se, Te, Pb, or the like.
  • the invented magnets are different from the ribbon magnets in the following several points. That is to say, the ribbon magnets can exhibit permanent magnetic properties in a transition stage from the amorphous or metastable crystal phase to the stable crystal state. Reportedly, the ribbon magnets can exhibit high coercive force only if the amorphous state still remains, or otherwise metastable Fe 3 B and R 6 Fe 23 are present as the major phases.
  • the invented magnets have no signs of any alloy phase remaining in the amorphous state, and the major phases thereof are not Fe 3 B and R 6 Fe 2a ,
  • the magnets of the present invention When the magnets of the present invention are prepared, use may be made of granulated powders (on the order of several tens-several hundreds pm) obtained by adding binders and lubricants to the alloy powders.
  • the binders and lubricants are not usually employed for the forming of anisotropic magnets, since they disturb orientation. However, they can be incorporated into the magnets of the present invention, since the inventive magnets are isotropic. Furthermore, the incorporation of such agents would possibly result in improvements in the efficiency of compacting and the strength of the compacted bodies.
  • the isotropic permanent magnets obtained according to the present invention have the magnetic properties higher than those of all the existing isotropic permanent magnets and, moreover, do not require to rely upon expensive ingredients such as Sm and Co.
  • the present invention is also highly advantageous in that it is possible to manufacture magnet products of practically sufficient bulk that is by no means achieved in the proposed amorphous ribbon process.
  • the FeBR base isotropic permanent magnets according to the first-third aspects of the present invention give high magnetic properties, making use of inexpensive R materials such as light rare earth (especially Nd, Pr, etc.), particularly various mixtures of light- and heavy-rare earth.
  • inexpensive R materials such as light rare earth (especially Nd, Pr, etc.), particularly various mixtures of light- and heavy-rare earth.
  • additional elements M are added to the FeBR base alloys as disclosed in the first-third aspects to contemplate improving in principle the coercive force iHc thereof.
  • the incorporation of M gives rise to a steep increase in iHc upon increase in the amount of B or R.
  • B or R increases Br rises and decreases after depicting a maximum value, wherein M brings about increase of iHc just in a maximum range of Br.
  • M use may be made of one or more of Al, Ti, V, Cr, Mn, Zr, Hf, Nb, Ta, Mo, Ge, Sb, Sn, Bi, Ni and W.
  • the coercive force iHc drops with increases in temperature.
  • the resulting properties appear by way of the synthesis of the properties of the individual elements, which varies depending upon the proportion thereof.
  • the amounts of the individual elements M are within the aforesaid ranges, and the combined amount thereof is no more than the maximum value determined with respect to the individual elements which are actually added.
  • the amount of M is determined such that the obtained magnets have a Br value equivalent to, or greater than, that of the conventional hard ferrite magnets and a coercive force equivalent to, or greater than, that of the conventional products.
  • Preferable amounts of M may be determined by selecting the amounts of M in which, e.g., Br of no less than 0.4 T (4.0 kG) and no less than 0.6 T (6.0 kG) or any desired value between Br of 0.2-0.65 T (2-6.5 kG) or higher is obtained as shown in Figs. 7 and 8.
  • M is a range of M as hereinbelow specified for obtaining Br of 0.6 T (6 kG) or higher: wherein the same is applied when two or more of M are added.
  • the range of M is most preferably 0.1-3.7% to achieve (BH)max of about 56 kJ/m 3 (7 MGOe), taking into consideration the effects thereof upon the increase in iHc and the lowering of Br as well as upon (BH)max.
  • M V, Nb, Ta, Mo, W, Cr and AI are preferred, while a minor amount of AI is particularly useful.
  • the FeBRM base sintered bodies have a mean crystal grain size within a given constant range. That is, iHc of no less than 79.6 kA/m (1 kOe) is satisfied, when the mean crystal grain size of the sintered bodies is in a range of about 1 to about 100 pm.
  • a preferable range is 1-80 pm and a most preferable range is 2-30 pm wherein further enhanced iHc is obtained.
  • Producing process is substantially the same as the third aspect except for preparation of the starting alloys or alloy powders.
  • the additional elements M may be added to the FeBR base alloy(s) or may be prepared as FeBRM alloys. Minor amount of alloys of the constitutional elements of Fe, B, R and M may be added to the mother alloys for formulating the final composition.
  • the permanent magnets according to the seventh aspect of the present invention may permit the entrainment of the elements A in quantities in or below given %.
  • A includes Cu, S, C, P, Ca, Mg, O, Si and the like.
  • FeBR and FeBRM base magnets When the FeBR and FeBRM base magnets are industrially prepared, such elements may often be entrained therein from the raw materials, the process of production, etc. For instance, when FeB is used as the raw material, S and P may often be entrained. In most cases, C remains as the residue of organic binders (compacting-aids) used in the process of powder metallurgy. Cu is frequently contained in cheap raw materials. Ca and Mg may easily be entrained from reducing agents. It has been observed that as the amount of entrained A increases, the residual magnetic flux density Br tends to drop.
  • the combined amount of (M+A) is no more than the highest upper limit of the upper limits of the elements actually added and entrained, as is substantially the case with two or more M or A. This is because both M and A are apt to decrease Br.
  • the resulting Br property appears through the synthesis of the effects of the individual elements upon Br, which varies depending upon the proportion thereof.
  • AI may be entrained from a refractory such as an alumina crucible into the alloys, but offers no disadvantage since it is useful as M.
  • M and A have no essential influence upon Curie point Tc, as long as they are within the presently claimed compositional range.
  • electrolytic iron of 99.9% purity was used as Fe; ferroboron alloys and boron of 99% purity used as B; and Nd, Pr, Dy, Sm, Ho, Er and Ce each of 99% purity or higher used as R (impurities were mainly other rare-earth metals).
  • the starting materials were melted by high-frequency melting, and cast in a water-cooled copper mold.
  • M use was made of Ti, Mo, Bi, Mn, Sb, Ni, Ta, Sn and Ge each of 99% purity, W of 98% purity, AI of 99.9% purity, and Hf of 95% purity.
  • ferrovanadium containing 81.2% of V, ferroniobium containing 67.6% of Nb, ferrochromium containing 61.9% of Cr and ferrozirconium containing 75.5% of Zr were used as V, Nb, Cr and Zr, respectively.
  • the unit of purity hereinabove is % by weight.
  • Coarse pulverization was carried out to 0.420 mm (35-mesh through) in a stamp mill, and fine pulverization done in a ball mill for 3 hours to 3-10 pm.
  • the alloys containing as R, Nd, Pr, Dy and Sm are exemplified, 15 rare-earth elements (Y, Ce, Sm, Eu, Tb, Dy, Er, Tm, Yb, Lu, Nd, Pr, Gd, Ho and La) show a substantially similar tendency.
  • the alloys containing Nd and Pr as the main component are much more useful than those containing scarce rare earth (Sm, Y, heavy rare earth) as the main ingredient, since rare earth ores abound relatively with Nd and Pr and, in particular, Nd does not still find any wide use.
  • the permanent magnets of the present invention can be prepared with the use of commercially available materials, and it is very advantageous to use the light rare-earth elements as the key component of magnet materials. While heavy rare earth is generally of less industrial value due to the fact that it is resourceless and espensive, it may be used alone or in combination with light rare earth.
  • the present invention provides permanent magnets comprising magnetically isotropic sintered bodies based on FeBR, FeBRM, FeBRA and FeBRMA base alloys, whereby magnetic properties equal to, or greater than, those achieved in the prior art are realized particularly without recourse to resourceless or expensive materials.
  • the isotropic sintered bodies of the present invention provide practical permanent magnets, which are excellent in view of resources, prices and magnetic properties, using as R light rare earth such as Nd and Pr.
  • the present invention is industrially of high value.

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Claims (35)

1. Aimant permanent fritté isotrope, essentiellement constitué, en pourcentages atomiques, de 10 à 25% de R, où R représente au moins un élément des terres rares comprenant Y, 3 à 23% de B, le reste étant du fer et des impuretés inévitables, les particules frittées ayant un diamètre moyen du grain de cristal de 1 à 160 pm, des diamètres moyens du grain de cristal jusqu'à 80 pm étant exclus.
2. Procédé de production d'aimants permanents frittés isotropes, qui implique les étapes de fusion et de préparation d'alliages comprenant, en pourcentages atomiques, 10 à 25% de R où R représente au moins l'un des éléments des terres rares y compris Y, 3 à 23% de B et le reste étant du fer et des impuretés inévitables, à refroidir les alliages fondus résultants, à pulvériser les alliages résultants, à compacter les alliages pulvérisés et à fritter la masse compacte résultante dans des conditions choisies de manière que les particules frittées aient un diamètre moyen du grain de cristal de 1 à 160 pm, des diamètres moyens du grain de cristal jusqu'à 80 pm étant exclus.
3. Aimant tel que défini dans la revendication 1, dans lequel, parmi lesdites impuretés, Cu ne représente pas plus de 3,3%, S ne représente pas plus de 2,5%, C ne représente pas plus de 4,0%, P ne représente pas plus de 3,3%, Ca ne représente pas plus de 4,0%, Mg ne représente pas plus de 4,0%, O ne représente pas plus de 2,0% et Si ne représente pas plus de 5,0%, et lorsque deux ou plus de deux desdits éléments sont utilisés, la quantité totale desdits éléments est limitée à la valeur maximale de l'un desdits éléments individuels ajoutés.
4. Procédé suivant la revendication 2, dans lequel, parmi lesdites impuretés, Cu ne représente pas plus de 3,3%, S ne représente pas plus de 2,5%, C ne représente pas plus de 4,0%, P ne représente pas plus de 3,3%, Ca ne représente pas plus de 4,0%, Mg ne représente pas plus de 4,0%, 0 ne représente pas plus de 2,0% et Si ne représente pas plus de 5,0%, et lorsque deux ou plus de deux desdits éléments sont utilisés, la quantité totale desdits éléments est limitée à la valeur maximale de l'un desdits éléments individuels ajoutés.
5. Aimant suivant la revendication 1, comprenant en outre au moins un élément complémentaire M, où M représente:
Figure imgb0021
et et lorsque deux ou plus de deux desdits éléments M sont utilisés, la quantité totale de M est limitée à la valeur maximale de l'un des éléments individuels M ajoutés.
6. Aimant suivant la revendication 5, dans lequel les particules frittées ont un diamètre moyen du grain de cristal d'environ 1 à 100 pm, des diamètres moyens du grain de cristal jusqu'à 80 pm étant exclus.
7. Procédé suivant la revendication 2, comprenant en outre au moins un élément complémentaire M, où M représente:
Figure imgb0022
et et lorsque deux ou plus de deux desdits éléments sont utilisés, la quantité totale de M est limitée à la valeur maximale de l'un des éléments individuels M ajoutés.
8. Procédé suivant la revendication 7, dans lequel le frittage est effectué dans des conditions telles que les particules frittées aient un diamètre moyen du grain de cristal de 1 à 100 pm, des diamètres moyens du grain de cristal allant jusqu'à 80 pm étant exclus.
9. Aimant tel que défini dans la revendication 5 ou 6, dans lequel, parmi lesdites impuretés (A), Cu ne représente pas plus de 3,3%, S ne représente pas plus de 2,5%, C ne représente pas plus de 4,0%, P ne représente pas plus de 3,3%, Ca ne représente pas plus de 4,0%, Mg ne représente pas plus de 4,0%, 0 ne représente pas plus de 2,0% et Si ne représente pas plus de 5,0%, et lorsqu'un ou deux ou plus de deux desdits éléments M et, respectivement, A sont utilisés, la quantité totale de (M+A) est limitée à la valeur maximale de l'un des éléments individuels M et A ajoutés.
10. Procédé suivant la revendication 7 ou 8, dans lequel, parmi lesdites impuretés, Cu ne représente pas plus de 3,3%, S ne représente pas plus de 2,5%, C ne représente pas plus de 4,0%, P en représente pas plus de 3,3%, Ca ne représente pas plus de 4,0%, Mg ne représente pas plus de 4,0%, O ne représente pas plus de 2,0% et Si ne représente pas plus de 5,0%, et lorsqu'un ou deux ou plus de deux desdits éléments M et, respectivement, A sont utilisés, la quantité totale de (M+A) est limitée à la valeur maximale de l'un des éléments individuels M et A ajoutés.
11. Aimant tel que défini dans la revendication 1, 5 ou 6, dans lequel, en pourcentages atomiques, R représente 12 à 20% et B représente 5 à 18%.
12. Aimant tel que défini dans la revendication 11, dans lequel R représente 12 à 16% et B représente 6 à 18%.
13. Procédé tel que défini dans la revendication 2, 7 ou 8, dans lequel, en pourcentages atomiques, R représente 12 à 20% et B représente 5 à 18%.
14. Procédé tel que défini dans la revendication 13, dans lequel R représente 12 à 16% et B représente 6 à 18%.
15. Aimant tel que défini dans la revendication 1, 5 ou 6, dans lequel R contient 50% ou plus de 50% d'éléments légers des terres rares.
16. Aimant tel que défini dans la revendication 15, dans lequel R contient 50% ou plus de 50% de Nd et/ou de Pr.
17. Aimant tel que défini dans la revendication 16, dans lequel, en pourcentages atomiques, R représente environ 15% et B représente environ 8%.
18. Procédé tel que défini dans la revendication 2, 7 ou 8, dans lequel R contient 50% ou plus de 50% d'éléments légers des terres rares.
19. Procédé tel que défini dans la revendication 18, dans lequel R contient 50% ou plus de 50% de Nd et/ou de Pr.
20. Procédé tel que défini dans la revendication 19, dans lequel, en pourcentages atomiques, R représente environ 15% et B représente environ 8%.
21. Aimant tel que défini dans la revendication 1, 5 ou 6, dans lequel la phase principale est formée par un alliage du type FeBR ayant une structure cristalline principalement tétragonale.
22. Aimant tel que défini dans la revendication 1, 5 ou 6, qui contient 1% en volume ou plus d'une phase riche en terres rares.
23. Aimant tel que défini dans la revendication 1, 5 ou 6, qui a une valeur (BH)max non inférieure à 16 kJ/m3 (2 MGOe).
24. Aimant tel que défini dans la revendication 11, qui a une valeur (BH)max non inférieure à 32 kJ/m3 (4 MGOe).
25. Aimant tel que défini dans la revendication 12, qui a une valeur (BH)max non inférieure à 56 kJ/m3 (7 MGOe).
26. Aimant tel que défini dans la revendication 5 ou 6, dans lequel des éléments complémentaires M sont contenus en proportions ou au-dessous des proportions suivantes, en pourcentages atomiques:
Figure imgb0023
et et lorsque deux ou plus de deux desdits éléments M sont utilisés, la quantité totale de M est limitée à la valeur maximale de l'un des éléments individuels M ajoutés.
27. Procédé tel que défini dans la revendication 7 ou 8, dans lequel des éléments complémentaires M sont utilisés dans les proportions ou au-dessous des proportions suivantes, indiquées en pourcentages atomiques:
Figure imgb0024
et et lorsque deux ou plus de deux desdits éléments M sont utilisés, la quantité totale de M est limitée à la valeur maximale de l'un des éléments individuels M ajoutés.
28. Aimant tel que défini dans la revendication 12, dans lequel des éléments complémentaires M sont présents en proportions ou au-dessous des proportions suivantes exprimées en pourcentages atomiques:
Figure imgb0025
et et lorsque deux ou plus de deux desdits éléments M sont utilisés, la quantité totale de M est limitée à la valeur maximale de l'un des éléments individuels M ajoutés.
29. Procédé tel que défini dans la revendication 14, dans lequel les éléments complémentaires M sont utilisés en proportions ou au-dessous des proportions suivantes exprimées en pourcentages atomiques:
Figure imgb0026
et et lorsque deux ou plus de deux desdits éléments M sont utilisés, la quantité totale de M est limitée à la valeur maximale de l'un des éléments individuels M ajoutés.
30. Aimant tel que défini dans la revendication 26, qui a une valeur Br non inférieure à 0,4 tesla (4 kG).
31. Aimant tel que défini dans la revendication 28, qui a une valeur Br non inférieure à 0,6 tesla (6 kG).
32. Aimant tel que défini dans la revendication 5 ou 6, dans lequel M est un ou plusieurs des éléments choisis dans le groupe comprenant V, Nb, Ta, Mo, W, Cr et AI.
33. Procédé tel que défini dans la revendication 2, 7 ou 8, dans lequel le frittage est effectué à une température de 900 à 1200°C.
34. Procédé tel que défini dans la revendication 33, dans lequel le frittage est effectué dans une atmosphère non oxydante ou réductrice.
35. Procédé tel que défini dans la revendication 34, dans lequel ladite atmosphère est le vide ou une pression réduite, ou un gaz inerte d'une pureté égale ou supérieure à 99,9%, sous une pression de 133 à 101 325 Pa (1-760 torrs).
EP19830113252 1983-05-06 1983-12-30 Aimants permanents isotropes et procédé pour leur fabrication Expired EP0124655B1 (fr)

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JP79098/83 1983-05-06
JP58079096A JPS59204209A (ja) 1983-05-06 1983-05-06 等方性永久磁石材料
JP79096/83 1983-05-06
JP58079098A JPS59204211A (ja) 1983-05-06 1983-05-06 等方性永久磁石材料

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6926777B2 (en) 1999-12-22 2005-08-09 Vacuumschmelze Gmbh & Co. Kg Method for producing rod-shaped permanent magnets
WO2007088422A2 (fr) * 2005-12-19 2007-08-09 Dymo Bande magnetique

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1271394A (fr) * 1985-02-25 1990-07-10 Karen S. Canavan Alliage magnetique permanent a remanence accrue et composes et methode de fabrication de cet alliage
US4954186A (en) * 1986-05-30 1990-09-04 Union Oil Company Of California Rear earth-iron-boron permanent magnets containing aluminum
US4778542A (en) * 1986-07-15 1988-10-18 General Motors Corporation High energy ball milling method for making rare earth-transition metal-boron permanent magnets
US4829277A (en) * 1986-11-20 1989-05-09 General Motors Corporation Isotropic rare earth-iron field magnets for magnetic resonance imaging
US4849035A (en) * 1987-08-11 1989-07-18 Crucible Materials Corporation Rare earth, iron carbon permanent magnet alloys and method for producing the same
DE4027598C2 (de) * 1990-06-30 1997-09-11 Vacuumschmelze Gmbh Dauermagnet des Typs SE-Fe-B und Verfahren zu seiner Herstellung
DE4135403C2 (de) * 1991-10-26 1994-06-16 Vacuumschmelze Gmbh SE-Fe-B-Dauermagnet und Verfahren zu seiner Herstellung
DE19636284C2 (de) * 1996-09-06 1998-07-16 Vacuumschmelze Gmbh SE-Fe-B-Dauermagnet und Verfahren zu seiner Herstellung
DE19636285C2 (de) * 1996-09-06 1998-07-16 Vakuumschmelze Gmbh Verfahren zur Herstellung eines SE-Fe-B-Dauermagneten
DE19636283A1 (de) * 1996-09-06 1998-03-12 Vacuumschmelze Gmbh Verfahren zur Herstellung eines SE-FE-B-Dauermagneten
DE19945943B4 (de) * 1999-09-24 2005-06-02 Vacuumschmelze Gmbh Borarme Nd-Fe-B-Legierung und Verfahren zu deren Herstellung
DE19945942C2 (de) * 1999-09-24 2003-07-17 Vacuumschmelze Gmbh Verfahren zur Herstellung von Dauermagneten aus einer borarmen Nd-Fe-B-Legierung
US6966953B2 (en) * 2002-04-29 2005-11-22 University Of Dayton Modified sintered RE-Fe-B-type, rare earth permanent magnets with improved toughness
US6994755B2 (en) * 2002-04-29 2006-02-07 University Of Dayton Method of improving toughness of sintered RE-Fe-B-type, rare earth permanent magnets
EP1712652A4 (fr) 2004-06-22 2010-10-13 Shinetsu Chemical Co Materiau magnetique permanent de terre rare a base de r-fe-b.
CN110957092B (zh) * 2019-12-19 2021-06-11 厦门钨业股份有限公司 R-t-b系磁体材料、原料组合物及制备方法和应用

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1316375C (fr) * 1982-08-21 1993-04-20 Masato Sagawa Materiaux magnetiques et aimants permanents
US4597938A (en) * 1983-05-21 1986-07-01 Sumitomo Special Metals Co., Ltd. Process for producing permanent magnet materials

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6926777B2 (en) 1999-12-22 2005-08-09 Vacuumschmelze Gmbh & Co. Kg Method for producing rod-shaped permanent magnets
WO2007088422A2 (fr) * 2005-12-19 2007-08-09 Dymo Bande magnetique
WO2007088422A3 (fr) * 2005-12-19 2008-12-31 Dymo Nv Bande magnetique

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SG49090G (en) 1990-08-17
CA1277159C (fr) 1990-12-04

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