USRE37666E1 - Iron-based permanent magnets and their fabrication as well as iron-based permanent magnet alloy powders for permanent bonded magnets and iron-based bonded magnets - Google Patents

Iron-based permanent magnets and their fabrication as well as iron-based permanent magnet alloy powders for permanent bonded magnets and iron-based bonded magnets Download PDF

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USRE37666E1
USRE37666E1 US09/660,437 US66043700A USRE37666E US RE37666 E1 USRE37666 E1 US RE37666E1 US 66043700 A US66043700 A US 66043700A US RE37666 E USRE37666 E US RE37666E
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iron
phase
permanent magnet
magnet
powder
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Hirokazu Kanekiyo
Satoshi Hirosawa
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Hitachi Metals Ltd
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Sumitomo Special Metals Co Ltd
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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
    • 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
    • B22F9/002—Making metallic powder or suspensions thereof amorphous or microcrystalline
    • B22F9/008—Rapid solidification processing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
    • 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
    • H01F1/0576—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 pressed, e.g. hot working
    • 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
    • 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
    • H01F1/0578—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 bonded together
    • 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
    • H01F1/0579—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B with exchange spin coupling between hard and soft nanophases, e.g. nanocomposite spring magnets

Definitions

  • This invention relating to iron-based permanent magnets and alloy powders for iron-based bonded magnets and their fabrication, used for obtaining suitable iron-based bonded magnets for all kinds of motors, actuators and magnetic circuits for magnetic sensors, as well as magnetic rolls and speakers, regards iron-based permanent magnets and their fabrication which yield isotropic iron-based bonded magnets having a residual magnetic flux density Br greater than 5 kG unobtainable from hard ferrite magnets.
  • Permanent magnets used in stepping motors, power motors and actuators utilized in home electronic goods and electric goods in general are mainly limited to hard ferrites, which have various problems such as, demagnetization at low temperatures with the fall of iHc, the ease of formation of defects, cracks and a lowering of mechanical strength due to the quality of the a ceramic material, and the difficulty to fabricate complicated forms.
  • These days, along with the miniaturization of home electronics and OA equipment small, light-weight magnetic materials to be used in these products are being sought.
  • motor vehicles as much effort is being made towards saving money and resources by making vehicles light-weighted, even more small, light-weight electrical components for motor vehicles are being sought.
  • Nd—Fe—B-type bonded magnet For example, for a Nd—Fe—B-type bonded magnet to satisfy such magnetic characteristics, 10 ⁇ 15 at % of Nd needs to be included making their cost incredibly high compared to hard ferrite magnets. Production of Nd requires many metal separation and reduction processes which in turn needs large scale equipment. As well as this, for 90% magnetization, a magnetic field of close to 20 kOe is required and there are problems with the magnetization characteristics such as being unable to achieve complicated multipole magnetization such that the pitch between the magnetic poles is less than 1.6 mm.
  • Nd—Fe—B-type magnet whose main component is an Fe 3 B-type compound with a composition close to Nd 4 Fe 77 B 19 (at %) (R. Coehoorn et al., J. De Phys., C8, 1988, 669 ⁇ 670).
  • This permanent magnet has a semi-stable structure with a crystal cluster structure in which a soft magnetic Fe 3 B phase and a hard magnetic Nd 2 Fe 14 B phase coexist.
  • it is insufficient as a rare earth magnetic material with a low iHc in the range 2 kOe ⁇ 3 kOe, and is unsuitable for industrial use.
  • Nd—Fe—B-type magnets whose main phase is an Fe 3 B-type compound
  • This incapability of providing a high-enough iHc is caused by a large grain size of the soft magnetic phase, typically 50 nm, which is not small enough to effectively prevent magnetization rotation in the soft magnetic phase from occurring under of a demagnetization field.
  • this invention provides iron-based permanent magnet alloy powders for iron-based permanent magnets suitable for bonded magnets and iron-based bonded magnets, and their fabrication.
  • both soft magnetic phases consisting of a ferromagnetic alloy whose main components are ⁇ -Fe and iron-based phase
  • hard magnetic phases having a Nd 2 Fe 14 B-type crystal structure will coexist within the same powder particles, and so, for mean crystal particle sizes of each constituent phase in the range of 1 nm ⁇ 30 nm, an intrinsic coercive force above the realistically required 5 kOe is apparent and, by molding magnetic powder having a particle size of 3 ⁇ m ⁇ 500 ⁇ m into the required forms using a resin, they can obtain permanent magnets in a usable form.
  • microcrystal clusters where the mean crystal size of each component phase is in the range 1 nm ⁇ 30 nm and where both a soft magnetic phase consisting of a ferromagnetic alloy whose main components are ⁇ -Fe and a alloy with iron as its mainphase, and a hard magnetic phase having a Nd 2 Fe 14 B-type crystal structure coexist within the same powder particles.
  • a soft magnetic phase consisting of a ferromagnetic alloy whose main components are ⁇ -Fe and a alloy with iron as its mainphase
  • a hard magnetic phase having a Nd 2 Fe 14 B-type crystal structure coexist within the same powder particles.
  • iron-based permanent magnet alloy powders suitable for bonded magnets having a residual magnetic flux density Br above 5 kG by grinding this material as required to a mean powder particle size of 3 ⁇ m ⁇ 500 ⁇ m and so can obtain iron-based permanent magnet alloy powders having the following magnetic characteristics.
  • FIG. 1 displays a graph showing the magnetization curve of a bonded magnet, given as an actual example, where this curve has been found by pulse magnetizing the magnet from a weak magnetic field in the range 2 kOe ⁇ 50 kOe and each time measuring the residual magnetic flux density at the open magnetic circuit. By taking the magnetization measured for the residual magnetic flux density at 50 kOe as 100%, the magnetization curve is found by estimating the magnetization rate for each magnetization field as a relative ratio of the residual magnetic flux density.
  • One of the focal points of this invention is the grain saize of the soft magnetic phase which is to consist the fine crystalline aggregate together with the Nd 2 Fe 14 B type hard magnetic phase.
  • the grain size must be much smaller than 50nm, which is the typical grain size of the previously existing magnet material, eg. Cochoorn et al. (1988).
  • composition and processing method are largely specified as follows.
  • the composition range is 10 at % ⁇ 30 at %.
  • the best range for B is 15 at % ⁇ 20 at %.
  • adding Cr causes the crystal particles to be about 1 ⁇ 4 ⁇ 1 ⁇ 4 times smaller compared to compositions without Cr, and as we can increase the magnetocrystalline anisotropy constant of the R 2 Fe 14 B phase by partially replacing the iron atoms in this hard magnetic phase with Cr, it is effective for raising iHc. This is ineffective, however, for Cr compositions less than 0.01 at %.
  • Cr couples antiferromagnetically with Fe, Br and the squareness of the demagnetization curve are greatly reduced, and so we cannot obtain a Br above 8 kG with a Cr composition greater than 7 at %.
  • the Cr composition range is 0.01 at % ⁇ 7 at %.
  • a composition of 0.01 at % ⁇ 3 at % is desirable.
  • an iHc above 6 kOe a Cr composition exceeding 3 at and up to % 7 at % is desirable.
  • the elements M are added with the purpose of improving the degradation of the squareness of the demagnetization curve on the addition of Co or Cr and to increase Br and (BH)max. This effect cannot be obtained for a composition less than 0.01 at %, and a composition beyond 10 at % further degrades the squareness and also lowers (BH)max, giving us a composition range of 0.01 at % ⁇ 10 at %.
  • the desirable range is 0.5 at % ⁇ 3 at %.
  • Fe makes up the remaining composition. Reasons for limiting the size of the crystal or powder particles.
  • the crystal phase of the magnetic powder that constitutes the bonded magnet of this invention will have both a soft magnetic phase consisting of a ferromagnetic alloy whose main components are ⁇ -Fe and iron, and a hard magnetic phase having a Nd 2 Fe 14 B-type crystal structure coexisting within the same powder, but without the latter hard magnetic phase, an iHc would not appear.
  • the average particle size of the powder must be sufficiently small, as high precision molding cannot be performed for powders larger than 500 ⁇ m. Also, for sizes less than 3 ⁇ m, the comparative increase in the surface area means that much resin must be used as a bonder, and as it is undesirable for the packing density to be too small, the particle size is limited to 3 ⁇ m ⁇ 500 ⁇ m.
  • microcrystal clusters where the average crystal size of each component phase is in the range 1 nm ⁇ 30 nm and where both soft magnetic phases consisting of a ferromagnetic alloy whose main components are ⁇ -Fe or iron-base intermetallic compound and hard magnetic phases having a Nd 2 Fe 14 B-type crystal structure coexist within the same powder particles.
  • melt-quenching method using a rotary roll may be employed if one is able to obtain an essentially amorphous structure or a structure where small amounts of microcrystals are dispersed in amorphous matrix.
  • Methods other than melt-quenching using a rotary roll may also be employed such as splat quenching, gas atomizing or a combination of these techniques.
  • a circumferential velocity of the rotor in the range of 10 m/sec ⁇ 50 m/sec is desirable as one can obtain a suitable quenched structure. That is, if the surface velocity is less than 10 m/sec, we cannot obtain the desired amorphous structure. Further, a circumferential velocity exceeding 50 m/sec is undesirable a microcrystal clusters having good hard magnetic properties do not form on crystallization. However, small amounts of ⁇ -Fe phase or meta-stable Nd—Fe—B compound within the quenched structure may be permitted as they do not significantly reduce the magnetization characteristics.
  • the heat treatment giving the best magnetic properties depends on the particular composition. Below a heat treatment temperature of 600° C., the Nd 2 Fe 14 B phase does not precipitate and no iHc will be apparent, and for a temperature exceeding 750° C., the particle growth is significant, degrading iHc, Br and the squareness of the demagnetization curve, meaning we cannot obtain the magnetic characteristics described above. Thus, the heat treatment temperature is limited to 600° C. ⁇ 750° C.
  • the magnetic properties of the obtained alloy powder are mostly independent of the heat treatment time, but we can say that after six hours, there is a trend towards a fall in Br with the passage of time, so a heat treatment time of less than six hours is desirable.
  • an important process parameter of this invention is the speed at which the temperature is raised from a temperature close to that of the start of crystallization during the heat treatment, and if this heating rate velocity is less than 10° C. per minute, particle growth occurs during the temperature rise and we cannot obtain microcrystal clusters having good hard magnetic properties, nor an iRc above 5 kOe. Further, if the heating rate exceeds 50° C. per minute, insufficient precipitation of the Nd 2 Fe 14 B phase which forms below 600° C. occurs, and, not only is iHc reduced, but we have a demagnetization curve with a fall in the magnetization near the Br point of the second quadrant of the magnetization curve, and (BH)max will also fall.
  • the bonded magnet relating to this invention is an isotropic magnet, and may be fabricated by any of the known methods listed below such as compression molding, injection molding, extrusion molding, roll molding and resin impregnation.
  • thermosetting resin For compression molding, after mixing the magnetic powder into a thermosetting resin, a coupling agent and a lubricating agent, heating up to a setting temperature after compression molding will cause the heated resin to harden.
  • thermosetting resin for resin impregnation, after compression molding the magnetic powder and heat treating as necessary, one can impregnate a thermosetting resin, and the resin will harden on heating. Further, after compression molding the magnetic powder and heat treating as necessary, one can also impregnate a heat plastic resin.
  • the weight ratio of the magnetic powder within the bonded magnet differs from previous fabrications being 70 wt % ⁇ 99.5 wt %, the remaining 0.5 wt % ⁇ 30 wt % being resin.
  • the desired weight ratio of the magnetic powder is 95 wt % ⁇ 99.5 wt %
  • the desired packing ratio of the magnetic powder is 90 wt % ⁇ 95 wt %
  • the desired weight ratio of the magnetic powder is 96 wt % ⁇ 99.5 wt %.
  • thermosetting or heat plasticity properties for the synthetic resin used for this invention, one can use a resin having either thermosetting or heat plasticity properties, with a thermally stable resin being desirable.
  • a resin having either thermosetting or heat plasticity properties for example, we recommend polyamide, polyimide, phenol resin, fluororesin, silicon resin or epoxy resin.
  • compositions No. 1 ⁇ 18 shown in Table 1 a total of 30 gr was weighed out using more than 99.5% pure Fe,Co,Cr,B,Nd,Pr,Al,Si,S,Ni,Cu,Zn,Ga,Ag,Pt,Au or Pb metal, placed in a quartz crucible having a 0.8 mm diameter orifice in its base, and melted by high frequency heating under an Ar atmosphere at a pressure of 56 cmHg.
  • the molten surface was pressurized by Ar gas, and the molten alloy was injected from a height of 0.7 mm from the other surface of a Cu roll rotating at a circumferential velocity of 20 m/sec at room temperature, forming an melt quenched thin film 2 mm ⁇ 4 mm wide and 20 ⁇ m ⁇ 40 ⁇ m thick.
  • the obtained thin film was shown to be amorphous using characteristic Cu K ⁇ x-rays.
  • this thin film was then raised to above 580° C. ⁇ 600° C., at which crystallization begins, under an Ar atmosphere at the rate shown in Table 1, and then maintained for seven hours at the heat treatment temperature also shown in Table 1. Then, the thin film was cooled to room temperature and removed, forming a sample 2 mm ⁇ 4 mm wide, 20 ⁇ m ⁇ 40 ⁇ m thick and 3 mm ⁇ 5 mm long. The magnetic characteristics were measured using a VSM, with the results shown in Table 2.
  • This bonded magnet has a density of 6.0 gr/cm 3 and its magnetic characteristics are shown in Table 3.
  • melt-quenched thin films were produced under the same conditions as for actual example 1, using 99.5% pure Fe,Co,Cr, B,Nd,Pr and Ni.
  • the temperature of this thin flake was then raised to above 580° C. ⁇ 600° C., at which crystallization begins, under an Ar atmosphere at the rate shown in Table 1, and then maintained for seven hours at the heat treatment temperature also shown in Table 1, cooled to room temperature and removed, producing a sample 2 mm ⁇ 4 mm wide, 20 ⁇ m ⁇ 40 ⁇ m thick and 3 mm ⁇ 5 mm long, whose magnetic characteristics were measured using an VSM. These results are shown in Table 2.
  • sample No. 19 has a multiphase structure of ⁇ -Fe and Nd 2 Fe 14 B phases, with the main phase being the Fe 3 B phase.
  • the average crystal particle size is 50 nm, larger compared to the previous samples No. 1 ⁇ 18 and is comparable to average grain seizes in multi—phase magnets in the prior art.
  • Sample No. 20 has a multiphase structure consisting of ⁇ -Fe and Nd 2 Fe 14 B phases, and has a microstructure with the average crystal particle size being about 20 nm, the same as actual example 1, but the squareness of the demagnetization curve is degraded compared to sample No. 3, which contains Co.
  • Sample 21 has a large average crystal particle size of 50 nm, and we do not obtain an iHc above 5 kOe.
  • Sample No. 22 has a multiphase structure with mixed ⁇ -Fe, Fe 3 B and Nd 2 Fe 14 B phases, but the growth of the ⁇ -Fe phase is significant leading to a demagnetization curve with a fall in the magnetization at the Br point of the second quadrant of the magnetization curve, and we cannot obtain a (BH)max above 10 MGOe.
  • sample No. 23 insufficient Nd 2 Fe 14 B phase precipitates for the appearance of a coercive force, and we have no hard magnetism.
  • Sample No 24 has an average crystal particle size in the range 70 nm , with large crystals compared to sample No. 3 of the same composition, and so Br, iHc and (BH)max are degraded when compared to sample No 3.
  • the magnetization curve, shown in FIG. 1 After processing bonded magnet No. 3, which has the magnetic characteristics listed in Table 3, so that the permeance coefficient becomes 1, the magnetization curve, shown in FIG. 1, has been found by pulse magnetizing from a weak magnetic field in the range 2 kOe ⁇ 50 kOe and each time measuring the residual magnetic flux density of the magnet in the open magnetic configuration. By taking the magnetization rate for the residual magnetic flux density at 50 kOe as 100%, the curve is found by estimating the magnetization rate for each magnetization field as a relative ratio of the residual magnetic flux density. The magnetic field required for 90% magnetization is about 13 kOe.
  • the magnetic field required for 90% magnetization is about 19 kOe, a 6 kOe larger magnetic field compared to that for bonded magnet No. 3 which has Co added.
  • iron-based permanent magnets not only with a Br above 8 kG and an iHc above 5 kOe, but also with a good squareness of the second quadrant of the demagnetization curve and with good thermal and magnetization characteristics.
  • this invention can provide bonded magnets with a magnetic efficiency exceeding that of hard ferrite magnets and having an iHc above 5 kOe and a Br above 5.5 kG. Further, we can shorten the industrial process by complete molding into magnetic parts or magnets, and so these bonded magnets can realize the cost performance of sintered hard ferrites.

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US09/660,437 1993-12-10 2000-09-11 Iron-based permanent magnets and their fabrication as well as iron-based permanent magnet alloy powders for permanent bonded magnets and iron-based bonded magnets Expired - Lifetime USRE37666E1 (en)

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US29910594A 1994-09-02 1994-09-02
US53488895A 1995-09-27 1995-09-27
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US6478891B1 (en) * 1999-11-25 2002-11-12 Seiko Epson Corporation Ribbon shaped magnet material magnetic powder and rare earth bonded magnet
US6589367B2 (en) * 1999-06-14 2003-07-08 Shin-Etsu Chemical Co., Ltd. Anisotropic rare earth-based permanent magnet material
US6661328B2 (en) 2000-04-28 2003-12-09 Matsushita Electric Industrial Co., Ltd. Composite magnetic body, and magnetic element and method of manufacturing the same

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JP3490228B2 (ja) * 1996-03-25 2004-01-26 アルプス電気株式会社 硬磁性合金圧密体およびその製造方法
DE69707185T2 (de) * 1996-04-10 2002-06-27 Showa Denko Kk Gusslegierung für die Herstellung von Dauermagneten mit seltenen Erden und Verfahren zur Herstellung dieser Legierung und dieser Dauermagneten
EP0823713B1 (en) * 1996-08-07 2003-04-02 Toda Kogyo Corporation Rare earth bonded magnet and rare earth-iron-boron type magnet alloy
EP0959478B1 (en) 1997-02-06 2004-03-31 Sumitomo Special Metals Company Limited Method of manufacturing thin plate magnet having microcrystalline structure
DE69823252T2 (de) * 1997-02-20 2005-04-14 Alps Electric Co., Ltd. Dauermagnetlegierung, Dauermagnetlegierungs-Pressling und Herstellungsverfahren dazu
US6332933B1 (en) 1997-10-22 2001-12-25 Santoku Corporation Iron-rare earth-boron-refractory metal magnetic nanocomposites
JP3275882B2 (ja) 1999-07-22 2002-04-22 セイコーエプソン株式会社 磁石粉末および等方性ボンド磁石
DE60031914T8 (de) * 1999-06-11 2007-10-31 Seiko Epson Corp. Magnetpulver und isotroper Verbundmagnet
EP1061533B1 (en) * 1999-06-11 2006-09-27 Seiko Epson Corporation Magnetic powder and isotropic bonded magnet
DE19945942C2 (de) * 1999-09-24 2003-07-17 Vacuumschmelze Gmbh Verfahren zur Herstellung von Dauermagneten aus einer borarmen Nd-Fe-B-Legierung
CN1162872C (zh) * 1999-12-27 2004-08-18 住友特殊金属株式会社 铁基磁性材料合金粉末的制造方法
CN101673605B (zh) * 2008-09-08 2011-12-07 南京理工大学 各向异性纳米/非晶复相块体永磁材料及其制备方法
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5022939A (en) * 1987-07-30 1991-06-11 Tdk Corporation Permanent magnets
US5049208A (en) * 1987-07-30 1991-09-17 Tdk Corporation Permanent magnets
US5209789A (en) * 1991-08-29 1993-05-11 Tdk Corporation Permanent magnet material and method for making
EP0542529A1 (en) * 1991-11-11 1993-05-19 Sumitomo Special Metal Co., Ltd. Method of making alloy powders of the RE-Fe/Co-B-M-type and bonded magnets containing this alloy powder

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2598558B2 (ja) * 1990-08-17 1997-04-09 富士電気化学株式会社 永久磁石
JP2966169B2 (ja) * 1991-11-11 1999-10-25 住友特殊金属株式会社 希土類磁石並びに希土類磁石用合金粉末とその製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5022939A (en) * 1987-07-30 1991-06-11 Tdk Corporation Permanent magnets
US5049208A (en) * 1987-07-30 1991-09-17 Tdk Corporation Permanent magnets
US5209789A (en) * 1991-08-29 1993-05-11 Tdk Corporation Permanent magnet material and method for making
EP0542529A1 (en) * 1991-11-11 1993-05-19 Sumitomo Special Metal Co., Ltd. Method of making alloy powders of the RE-Fe/Co-B-M-type and bonded magnets containing this alloy powder

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
H. Kanekiyo et al., "Microstrure and Magnetic Characteristics of High-Remanence Nd5Fe75 6Co5 B18 5 M (M=Al, Si, Ga, Ag, Au) Rapidly Solidified and Crystallized Alloys for Resin-Bonded Magnets", Digests of INTERnational MAGnetics Conferences, Apr. 13-16, 1993. *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6589367B2 (en) * 1999-06-14 2003-07-08 Shin-Etsu Chemical Co., Ltd. Anisotropic rare earth-based permanent magnet material
US6478891B1 (en) * 1999-11-25 2002-11-12 Seiko Epson Corporation Ribbon shaped magnet material magnetic powder and rare earth bonded magnet
US6661328B2 (en) 2000-04-28 2003-12-09 Matsushita Electric Industrial Co., Ltd. Composite magnetic body, and magnetic element and method of manufacturing the same
US6784782B2 (en) * 2000-04-28 2004-08-31 Matsushita Electric Industrial Co., Ltd. Composite magnetic body, and magnetic element and method of manufacturing the same
US20040209120A1 (en) * 2000-04-28 2004-10-21 Matsushita Electric Industrial Co., Ltd. Composite magnetic body, and magnetic element and method of manufacturing the same
US6888435B2 (en) 2000-04-28 2005-05-03 Matsushita Electric Industrial Co., Ltd. Composite magnetic body, and magnetic element and method of manufacturing the same
US7219416B2 (en) 2000-04-28 2007-05-22 Matsushita Electric Industrial Co., Ltd. Method of manufacturing a magnetic element

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CN1080920C (zh) 2002-03-13
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EP0657899B1 (en) 2000-03-08
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CN1105474A (zh) 1995-07-19
EP0657899A1 (en) 1995-06-14
DE69423305D1 (de) 2000-04-13

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