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WO2000048209A9 - Composition riche en praseodyme a base de fer, de bore et de terres rares, aimant permanent produit a partir de celle-ci et procede de production - Google Patents

Composition riche en praseodyme a base de fer, de bore et de terres rares, aimant permanent produit a partir de celle-ci et procede de production

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Publication number
WO2000048209A9
WO2000048209A9 PCT/US2000/002946 US0002946W WO0048209A9 WO 2000048209 A9 WO2000048209 A9 WO 2000048209A9 US 0002946 W US0002946 W US 0002946W WO 0048209 A9 WO0048209 A9 WO 0048209A9
Authority
WO
WIPO (PCT)
Prior art keywords
rare earth
percent
sintered
permanent magnet
present
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.)
Ceased
Application number
PCT/US2000/002946
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English (en)
Other versions
WO2000048209A1 (fr
Inventor
Mark Gilbert Benz
Juliana Ching Shei
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to AU34828/00A priority Critical patent/AU3482800A/en
Priority to JP2000599045A priority patent/JP2003525345A/ja
Priority to EP00913364A priority patent/EP1072044A1/fr
Publication of WO2000048209A1 publication Critical patent/WO2000048209A1/fr
Publication of WO2000048209A9 publication Critical patent/WO2000048209A9/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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 to permanent magnetic materials and the method of making the permanent magnet. More particularly, the invention relates to high performance sintered intermetallic materials containing an iron-boron-rare earth composition enriched with praseodymium.
  • Fe-B-RE iron-boron-rare earth type
  • Nd neodymium
  • computer hardware manufacturers who manufacture small footprint, large capacity computer data storage and retrieval hardware, use very high performance iron-boron- neodymium permanent magnets (the total rare earth being greater than 99 percent Nd).
  • medical devices such as magnetic resonance imaging (MRI) devices, employ vast quantities of permanent magnetic iron- boron-neody ium material, which contain greater than 90 percent of the total rare earth being neodymium.
  • MRI magnetic resonance imaging
  • Permanent magnets of the Fe-B-RE type where RE is one or more rare earth elements of which at least 50% of RE is neodymium and/ or praseodymium (Pr), are known.
  • U.S. Patents 4,684,406 and 4,597,938 teach a high performance magnet consisting of, by atomic percent, (i) 12.5 percent to 20 percent RE wherein RE is at least one rare earth element selected from the group consisting of neodymium, praseodymium, lanthanum, cerium, terbium, dysprosium, holmium, erbium, europium, samarium, gadolinium, promethium, thulium, ytterbium, lutetium and yttrium and at least 50% of RE consists of neodymium and/ or praseodymium; (ii) 4 percent to 20 percent boron; and (iii) the balance iron with impurities.
  • a method of making the magnet is taught by forming powders of the alloys of the above composition; melting the powders to form an ingot; pulverizing the ingot to form an alloy powder having a mean particle size from 0.3 to 80 microns; compacting the powder at a pressure of 0.5 to 8 Tons/ cm 2 ; subjecting the compacted body to a magnetic field of about 7 to 13 kOe; and then sintering at a temperature between 900 to 1,200°C
  • a permanent magnet prepared in the above fashion specifically comprised of by atomic percent 77Fe-9B-9Nd-5Pr, sintered at 1,120°C for four hours in an inert atmosphere can acquire a maximum energy product (BH)max of 31.0 MGOe.
  • a permanent magnet comprised of by atomic percent 79Fe-7B-14Nd, sintered at 1,120°C for one hour, can acquire a maximum energy product (BH)max of 33.8 MGOe.
  • U. S. Patent 4,908,078 shows a rare earth magnet article consisting of the three rare earth elements neodymium-praseodymium-cerium within defined atom ratios of each in the formula: (Nd ⁇ -(p+q)PrpCeq) x ByFe ⁇ -(x+ y ) wherein 0.1 ⁇ x ⁇ 0.3, 0.02 ⁇ y ⁇ 0.09, 0.1 ⁇ p ⁇ 0.3, and 0.02 ⁇ q ⁇ 0.15.
  • Praseodymium is 10 to 30 percent of the total rare earth and cerium is 2 to 15 percent of the rare earth with the balance neodymium.
  • the resultant magnet has a coercive force (He) of at least about 5 kOe and a residual magnetic flux density (Br) of at least about 10 kiloGauss (kG). Also, U. S.
  • Patent 5,129,963 discusses rare earth magnet alloys with excellent hot workability having compositions in atomic percent of 10 to 16 percent rare earth elements, 3 to 10 percent boron and about 74 to 87 percent iron (with or without cobalt) where the rare earth elements are neodymium and/ or praseodymium plus up to 20 percent of the rare earth is selected from cerium, lanthanum and/ or yttrium.
  • the present invention satisfies this need by providing a sintered intermetallic product comprising compacted and sintered particulate of an iron-boron-rare earth alloy having substantially non-interconnecting pores with a density of at least 87 percent of theoretical and where the alloy further comprises about 13 to about 19 atomic percent rare earth, where the rare earth content consists essentially of greater than 50 percent praseodymium, an effective amount of a light rare earth selected from the group consisting of cerium, lanthanum, yttrium and mixtures thereof, and balance neodymium; about 4 to about 20 atomic percent boron; and balance iron with or without impurities.
  • the phrase "praseodymium-rich" means that the rare earth content of the iron-boron-rare earth alloy contains greater than 50% praseodymium.
  • the percent praseodymium of the rare earth content is at least 70% and can be up to 100% depending on the effective amount of light rare earth present in the total rare earth content.
  • An effective amount of a light rare earth is an amount present in the total rare earth content of the iron-boron-rare earth alloy that allows the magnetic properties to perform equal to or greater than 29 MGOe (BH)max and 6 kOe (Hci).
  • the iron content of the alloy may be present with impurities, such as but not limited to, titanium, nickel, bismuth, cobalt, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, alurni ⁇ um, germanium, tin, zirconium, hafnium, and mixtures thereof.
  • impurities such as but not limited to, titanium, nickel, bismuth, cobalt, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, alurni ⁇ um, germanium, tin, zirconium, hafnium, and mixtures thereof.
  • Another embodiment of the invention comprises an isotropic alloy material of an iron-boron-rare earth type consisting essentially of in atomic percent about 13 to about 19 percent rare earth, where said rare earth comprises praseodymium in an amount greater than 50% of the total rare earth, an effective amount of a light rare earth selected from the group consisting of cerium, lanthanum, yttrium and mixtures thereof, and balance neodymium; about 4 to about 20 percent boron; and balance comprising iron with or without impurities.
  • Still another embodiment is a praseodymium-rich anisotropic permanent magnet of the iron-boron-rare earth type comprising in atomic percent about 13 to about 19 percent rare earth elements, about 4 to about 20 percent boron and about 61 to about 83 percent of iron with or without impurities; where the rare earth content is greater than 50 percent praseodymium with an effective amount of a light rare earth selected from the group consisting of cerium, lanthanum, yttrium and mixtures thereof, and balance neodymium; where the magnet consists essentially of substantially non-interconnecting pores having a density of at least 87 percent theoretical and substantially magnetically aligned grains of RE 2 FeuB tetragonal crystals.
  • the invention comprises a permanent magnet having substantially stable magnetic properties and having as the active magnetic component a sintered product of compacted particulate iron-boron-rare earth intermetallic material, said sintered product having pores which are substantially non-interconnecting, a density of at least 87 percent of theoretical and a composition consisting essentially of in atomic percent about 13 to about 19 percent rare earth elements, about 4 to about 20 percent boron and about 61 to about 83 percent of iron with or without impurities; where the rare earth content is greater than 50 percent praseodymium with an effective amount of a light rare earth selected from the group consisting of cerium, lanthanum, yttrium and mixtures thereof, and balance neodymium.
  • the present invention further comprises a sintered permanent magnetic material of the iron-boron-rare earth type made in accordance with the following process, namely: providing an alloy of iron-boron-rare earth in particulate form, said iron, boron, and rare earth being used in amounts substantially corresponding to that desired in the sintered permanent magnetic material and being comprised of a major amount of a iron-boron- rare earth intermetallic phase, pressing and compacting said particulate alloy into a green body, and sintering said green body in a substantially inert atmosphere to produce a sintered permanent magnetic material of the iron- boron-rare earth type having a density of at least 87 percent of theoretical with substantially non-interconnecting pores and a composition consisting essentially of in atomic percent about 13 to about 19 percent rare earth elements, about 4 to about 20 percent boron and about 61 to about 83 percent of iron with or without impurities; where the rare earth content is greater than 50 percent praseodymium with an effective amount of a light rare earth selected from the group consist
  • the invention further includes a method for making sintered permanent magnet of the iron-boron-rare earth type comprising the steps of: providing an alloy of iron-boron-rare earth in a particulate form where said particulate has a mean particle size of up to 60 microns, wherein the alloy particulate has a composition consisting essentially of, in atomic percent, about 13 to about 19 percent rare earth elements, about 4 to about 20 percent boron and about 61 to about 83 percent of iron with or without impurities; where the rare earth content is greater than 50 percent praseodymium with an effective amount of a light rare earth selected from the group consisting of cerium, lanthanum, yttrium and mixtures thereof, and balance neodymium; pressing and compacting said particulate alloy into a green body; and sintering said green body in a substantially inert atmosphere to produce a sintered permanent magnet having a density of at least about 87 percent of theoretical and consisting essentially of a substantially intermetallic RE 2 Fe 1 B
  • a further embodiment of the invention is a metallic powder having a mean particle size up to about 60 microns comprising a composition consisting essentially of about 13 to about 19 atomic percent rare earth, where the rare earth content consists essentially of greater than 50 percent praseodymium, an effective amount of a light rare earth selected from the group consisting of cerium, lanthanum, yttrium and mixtures thereof, and balance neodymium; about 4 to about 20 atomic percent boron; and balance iron with or without impurities.
  • FIG. 1 is a graph showing intrinsic coercive force as a function of praseodymium composition of RE in a Fe-B-RE type magnet, at cerium concentrations of 0.5% of RE.
  • FIG. 2 is a graph showing intrinsic coercive force as a function of praseodymium composition of RE in a Fe-B-RE type magnet, at cerium concentrations of 5.0-5.3% of RE.
  • FIG. 3 is a graph showing intrinsic coercive force as a function of praseodymium composition of RE in a Fe-B-RE type magnet, at cerium concentrations of 10% of RE.
  • FIG. 4 is a graph plotting intrinsic coercive force as a function of cerium concentration of RE at praseodymium concentrations between 50-60% of RE.
  • FIG. 5 is a graph plotting intrinsic coercive force as a function of cerium concentration of RE at praseodymium concentrations between 74.5- 100% of RE.
  • one of the discoveries of this invention is that while adding a light rare earth, such as cerium, to an iron-boron- praseodymium permanent magnet, where praseodymium is greater than 50 percent of the total rare earth, the magnetic performance is almost the same as an iron-boron-neodymium magnet, and in some cases the magnetic performance is enhanced. Accordingly, the inventor fotmd that low concentrations of light rare earth, such as cerium, lanthanum and yttrium with the balance of RE consisting essentially of greater than 50 percent praseodymium and the balance neodymium, produce a permanent magnet for magnetic resonance imaging at a reduced cost.
  • a light rare earth such as cerium
  • light rare earth refer to cerium, lanthanum and yttrium.
  • praseodymium is the primary rare earth present in the iron-boron-rare earth composition, and thus is not included in the category of light rare earth. With praseodymium always being greater than 50 percent of the total rare earth concentration, the light rare earth (cerium, lanthanum and yttrium) can be up to 30 percent. This is also a quantitative measure of an effective amount of the light rare earth in the overall composition. Preferably , the light rare earth is present up to 10 percent or less, and most preferably up to 5 percent or less.
  • magnet materials or magnets themselves can have up to 1 percent light rare earth with 0.5 percent light rare earth (cerium, lanthanum, yttrium) showing an improvement in the materials' intrinsic coercive force.
  • the light rare earth can be present individually or in a mixed amount. For instance, only cerium may be present as the light rare earth, or cerium and lanthanum may be present, or a mixture of cerium, lanthanum and yttrium may be present. Likewise, only lanthanum or yttrium may be present, or lanthanum and yttrium, or cerium and yttrium.
  • praseodymium is present in the isotropic alloy, the sintered intermetallic product, the anisotropic permanent magnet, and the permanent magnet having stable magnetic properties as greater than 50 percent of the total rare earth content.
  • praseodymium may be included up to 100 percent of the rare earth where there is no substantive amount of light rare earth or neodymium present in the composition.
  • compositions of this invention also may include the presence of a trace of heavy rare earth.
  • Heavy rare earths include elements selected from the group consisting of dysprosium, gadolinium, samarium, ytterbium, terbium, holmium and mixtures thereof.
  • a trace amount of heavy rare earth is less than one percent of the total rare earth content, and includes the range between about 0.2 to 0.9 percent.
  • the overall composition of this invention for an iron-boron-rare earth alloy and magnet is contemplated as comprising in atomic percent, about 13 to about 19 percent rare earth, about 4 to about 20 percent boron, and the balance iron.
  • the formula is represented as RE(;i3- 9)B(4-20)Fe(baiance). A more specific formula is demonstrated by 15.5RE-6.5B-78Fe. However, any appropriate formula falling within the ranges specified above for iron, boron and the rare earth is considered part of this invention. It is also contemplated that the iron may or may not include impurities.
  • impurities examples include titanium, nickel, bismuth, cobalt, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, aluminum, germanium, tin, zirconium, hafnium, and mixtures thereof.
  • the magnetic phase of this material consists of the tetragonal crystalline structure of RE 2 Fe ⁇ 4 B (in atomic percent).
  • Isotropic material of the iron-boron-rare earth type is an aspect of the invention.
  • This material is sometimes referred to as alloy or alloy material. Generally, it comprises in atomic percent, about 13 to about 19 percent rare earth, about 4 to about 20 percent boron, and the balance iron in particulate form or as an ingot.
  • the iron, boron, and rare earth metal are each used in amounts substantially corresponding to those desired in the final sintered product.
  • the alloy can be formed by a number of methods. For example, it can be prepared by arc- melting or induction melting the iron, boron and rare earth metal together in the proper amounts under a substantially inert atmosphere such as argon and allowing the melt to solidify. Preferably the melt is cast into an ingot.
  • the isotropic material (alloy) exists as an ingot, then it can be converted to particulate form in a conventional manner known by those skilled in the art.
  • the ingot undergoes a crushing or pulverizing step in order to form the particulate material.
  • Such conversion can be carried out in air at room temperature.
  • the isotropic material can be crushed by mortar and pestle and then pulverized to a finer form by jet milling.
  • Such powder may also be produced by known ball milling procedures, or Alpine jet milling.
  • the particle size of the iron-boron-rare earth alloy of the present invention may vary. It can be as finely divided as desired.
  • the alloy particulate can have a mean particle size up to 60 microns.
  • average particle size will range from about 1 to about 10 microns, or about 1 to about 7 microns, or about 3 to about 5 microns. It may be unusual, but the particulate material can even be up to 100 microns. While larger sized particles can be used, it is pointed out that as the particle size is increased, the maximum coercive force obtainable is lower because the coercive force generally varies inversely with particle size. In addition, the smaller the particle size, the lower is the sintering temperature which may be used.
  • the isotropic material exists prior to the application of a magnetic field. Once a magnetic field is applied, then particulate grains align themselves magnetically so that the principal magnetic phase is RE 2 Fe ⁇ B and the grains magnetically align along their easy axis. If the isotropic particulate (alloy) is exposed to an aligning magnetic field, it generally occurs before pressing and compacting the particulate into a green body, which is subsequently sintered.
  • the aligning magnetic field may also be applied during the pressing and compacting of the isotropic particulate.
  • the magnetic field that is applied is at least 7kOe and may range between about
  • the particulate material can be compressed or compacted into a green body of the desired size and density by any of a number of techniques know to those skilled in the art. Some of these techniques include hydrostatic pressing or methods employing steel dies. Preferably, compression is carried out to produce a green body with as high a density as possible, since the higher its density, the greater the sintering rate. Green bodies having a density of about fifty percent or higher of theoretical are recommended.
  • the green body is sintered to produce a sintered intermetallic product of desired density.
  • the green body is sintered to produce a sintered intermetallic product wherein the pores are substantially non- interconnecting.
  • Such non-interconnectivity stabilizes the permanent magnet properties of the product because the interior of the sintered intermetallic product or magnet is protected against exposure to the ambient atmosphere.
  • the sintering temperature used in the invention depends largely on the alloy composition RE( 3 - 9 )B( -20)Fe(baiance) that is selected and the particle size.
  • the minimum sintering temperature must be sufficient for sintering to occur in the selected alloy composition and it must be high enough to coalesce the particles.
  • Sintering is carried out so that the pores in the sintered intermetallic product are substantially non-interconnecting.
  • a sintered intermetallic product having a density of at least about 87 percent of theoretical is generally one wherein the pores are substantially non- interconnecting.
  • Non-interconnectivity can be determined by standard metallographic techniques, such as optical electron micrographs of a cross- section of the sintered product.
  • the maximum sintering temperature is usually one at which significant growth of the particles or grains does not occur, since too large an increase in grain size deteriorates magnetic properties such as coercive force.
  • the green body is sintered in a substantially inert atmosphere such as argon, and upon completion of sintering, the body can be cooled to room temperature in a substantially inert atmosphere.
  • a particular sintering range for a selected composition can be determined empirically, as for example, carrying out a series of runs at successively higher sintering temperatures and then determining the magnetic properties of the sintered intermetallic products.
  • the sintering temperature may be in the range of about 950 to about 1200°C for most compositions of this invention.
  • the sintering time varies but may lie between one and five hours.
  • the density of the sintered intermetallic product may vary. The particular density depends largely on the particular permanent magnet properties desired. Preferably, to obtain a product with substantially stable permanent magnet properties, the density of the sintered intermetallic product should be one wherein the pores are substantially non-interconnecting and this occurs usually at a density of about 87 percent or greater. However, for some applications, the density may be below 87 percent, such as the range from about 80 percent up to 100 percent. For example, at low temperature applications, a sintered intermetallic product having a density ranging down to about 80 percent may be satisfactory.
  • the preferred density of the sintered intermetallic product is one which is the highest obtainable without producing a growth in grain size which would deteriorate magnetic properties significantly, since the higher the density the better are the magnetic properties.
  • a density of at least about 87 percent of theoretical, i.e. of full density, and as high as about 96 percent of theoretical is preferred to produce permanent magnets with suitable magnetic properties which are substantially stable.
  • the final sintered intermetallic product contains a major amount of the RE 2 Fei4B solid intermetallic phase.
  • a major amount is greater than 50 percent by weight of the intermetallic product.
  • Sintered intermetallic products having the highest energy products are those having the smallest content of other iron-boron-rare earth intermetallic phases.
  • the preferred final sintered intermetallic product is comprised predominately of the RE 2 Fe 14 B solid intermetallic phase, i.e. about 95 percent by weight or higher but less than 100 percent.
  • Sintering of the green body produces a sintered product which weighs about the same as the green body indicating no loss, or no significant loss of iron, boron, and rare earth components. Standard chemical analysis of a sintered product should show that the rare earth and iron and boron content is substantially unaffected by the sintering process.
  • Magnetization of the present sintered intermetallic products of iron, boron and rare earth produces novel permanent magnets.
  • the magnetic properties of the present sintered intermetallic products can be improved by subjecting them to a heat-aging process.
  • the sintered intermetallic product is heat-aged at a temperature within 400°C below its sintering temperature and preferably within 300 to 100°C below its sintering temperature. Heat-aging is carried out in an atmosphere such as argon in which the material is substantially inert.
  • the particular temperature at which the material is heat- aged is determinable empirically.
  • the sintered product may be initially magnetized and its magnetic properties determined.
  • the sintered product can be heat-aged immediately after sintering, if desired, simply by lowering the furnace temperature, i.e. furnace cooling, to the desired heat-aging temperature.
  • Heat-aging by furnace cooling to the desired aging temperature is preferred. It requires a shorter period of time and generally produces a product with an intrinsic and/ or normal coercive force significantly higher than that produced by the technique of initially cooling the sintered product to room temperature and then heating it up to the proper heat-aging temperature.
  • the rate of furnace cooling should be slow with the particular furnace cooling rate being determinable empirically.
  • the furnace cooling rate may range from about 0.1 to about 20°C per minute depending largely on the particular iron-boron-rare earth alloy used.
  • the rate of furnace cooling may be carried out in a continuous manner or, if desired, by step cooling.
  • the heat-aged sintered intermetallic product of the present invention is useful as a permanent magnet.
  • the resulting permanent magnet is substantially stable in air and has a wide variety of uses.
  • the permanent magnets of the present invention are useful in magnetic resonance imaging devices.
  • the sintered bulk intermetallic product of the present invention can be crushed to a desired particle size preferably a powder, which is particularly suitable for alignment and matrix bonding to give a stable permanent magnet.
  • permanent magnet materials of the iron- boron-rare earth type of this invention may then be obtained having intrinsic coercive force (Hci) values of at least 6 kOe, and more likely above 8 kOe.
  • the corresponding maximum energy product values (BH)max are at least 29 MGOe, and more likely above 35 MGOe.
  • Table 1 shows samples created using the above methods, without heat-aging, which correspond to the compositions of this invention consisting of 78Fe-6.5B-15.5RE including the light rare earth cerium in the total rare earth content.
  • Fig. 4 shows a plot of magnetic performance Hci as a function of cerium addition, at relatively constant values of praseodymium (from greater than 50 to 60 wt. %).
  • Fig. 5 likewise shows a plot of magnetic performance Hci as a function of cerium addition, at relatively constant values of praseodymium (from about 75 to 100 wt. %).

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Hard Magnetic Materials (AREA)
  • Powder Metallurgy (AREA)

Abstract

L'invention concerne un aimant permanent possédant des propriétés magnétiques sensiblement stables et dont le constituant magnétique actif est un produit fritté d'un matériau intermétallique particulaire compacté à base de fer, de bore et de terres rares. Ce produit fritté présente des pores sensiblement non interconnectés, une densité théorique d'au moins 87 % et une composition constituée essentiellement, en pourcentage atomique, d'environ 13 à environ 19 % d'éléments de terres rares, d'environ 4 à environ 20 % de bore et d'environ 61 à environ 83 % de fer, avec ou sans impuretés. Le contenu en terres rares est constitué à plus de 50 % de praséodyme avec une quantité efficace d'une terre rare légère choisie parmi le cérium, le lanthane, l'yttrium et leurs mélanges, le reste étant du néodyme.
PCT/US2000/002946 1999-02-12 2000-02-03 Composition riche en praseodyme a base de fer, de bore et de terres rares, aimant permanent produit a partir de celle-ci et procede de production Ceased WO2000048209A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU34828/00A AU3482800A (en) 1999-02-12 2000-02-03 Praseodymium-rich iron-boron-rare earth composition, permanent magnet produced therefrom, and method of making
JP2000599045A JP2003525345A (ja) 1999-02-12 2000-02-03 プラセオジムに富む鉄−ホウ素−希土類組成物、それから作製した永久磁石、および作製方法
EP00913364A EP1072044A1 (fr) 1999-02-12 2000-02-03 Composition riche en praseodyme a base de fer, de bore et de terres rares, aimant permanent produit a partir de celle-ci et procede de production

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US24825199A 1999-02-12 1999-02-12
US09/248,251 1999-02-12

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WO2000048209A1 WO2000048209A1 (fr) 2000-08-17
WO2000048209A9 true WO2000048209A9 (fr) 2001-08-09

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CN100461308C (zh) * 2005-05-22 2009-02-11 横店集团东磁有限公司 一种超高矫顽力烧结钕铁硼磁性材料及其制备方法
JP2013157505A (ja) * 2012-01-31 2013-08-15 Minebea Co Ltd ボンド磁石の製造方法
WO2014148145A1 (fr) * 2013-03-22 2014-09-25 Tdk株式会社 Aimant permanent r-t-b
JP5708889B2 (ja) * 2013-03-22 2015-04-30 Tdk株式会社 Ｒ−ｔ−ｂ系永久磁石
WO2014148146A1 (fr) * 2013-03-22 2014-09-25 Tdk株式会社 Aimant permanent de type r-t-b
CN105469973B (zh) 2014-12-19 2017-07-18 北京中科三环高技术股份有限公司 一种r‑t‑b永磁体的制备方法
JP7676444B2 (ja) * 2020-12-09 2025-05-14 Tdk株式会社 Ｒ－ｔ－ｂ系永久磁石

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US4597938A (en) * 1983-05-21 1986-07-01 Sumitomo Special Metals Co., Ltd. Process for producing permanent magnet materials
JPH066775B2 (ja) * 1984-04-18 1994-01-26 セイコーエプソン株式会社 希土類永久磁石
JPS60228652A (ja) * 1984-04-24 1985-11-13 Nippon Gakki Seizo Kk 希土類磁石およびその製法
KR880013194A (ko) * 1987-04-06 1988-11-30 원본미기재 영구자석 및 그 제조방법

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AU3482800A (en) 2000-08-29
CN1133182C (zh) 2003-12-31
EP1072044A1 (fr) 2001-01-31
CN1296627A (zh) 2001-05-23
JP2003525345A (ja) 2003-08-26
WO2000048209A1 (fr) 2000-08-17

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