EP0331286A2 - Schnellverdichtung einer Seltenerd-Übergangsmetallegierung in einer mit Flüssigkeit gefüllten Matrize - Google Patents

Schnellverdichtung einer Seltenerd-Übergangsmetallegierung in einer mit Flüssigkeit gefüllten Matrize Download PDF

Info

Publication number
EP0331286A2
EP0331286A2 EP89300871A EP89300871A EP0331286A2 EP 0331286 A2 EP0331286 A2 EP 0331286A2 EP 89300871 A EP89300871 A EP 89300871A EP 89300871 A EP89300871 A EP 89300871A EP 0331286 A2 EP0331286 A2 EP 0331286A2
Authority
EP
European Patent Office
Prior art keywords
hot
alloy
transition metal
rare earth
container
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.)
Withdrawn
Application number
EP89300871A
Other languages
English (en)
French (fr)
Other versions
EP0331286A3 (de
Inventor
Peter Vernia
Elizabeth F. Harasek
Ronald G. Lanzi
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.)
Motors Liquidation Co
Original Assignee
General Motors Corp
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 Motors Corp filed Critical General Motors Corp
Publication of EP0331286A2 publication Critical patent/EP0331286A2/de
Publication of EP0331286A3 publication Critical patent/EP0331286A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/001—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a flexible element, e.g. diaphragm, urged by fluid pressure; Isostatic presses
    • B30B11/002—Isostatic press chambers; Press stands therefor
    • 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
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/1208—Containers or coating used therefor
    • 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
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • 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
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • B22F3/15—Hot isostatic pressing
    • 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
    • H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
    • H01F1/0556—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together pressed
    • 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
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing

Definitions

  • This invention relates to the hot-forming of rare earth-transition metal alloys to form densified compacts as specified in the preamble of claim 1, for example as disclosed in EP-A-0 133 758.
  • Permanent magnets based on compositions containing iron, neodymium and/or praseodymium, and boron are now in commercial usage. These magnets contain grains of tetragonal crystals in which the proportions of transition metal (TM), rare earth (RE), and boron are exemplified by the empirical formula RE2TM14B1 and where at least part of the transition metal is iron. These magnet compositions and methods for making them are described in EP-A-0 108 474 and EP-A-0 144 112 incorporated herein by reference. The grains of the tetragonal crystal phase are surrounded by a small amount of a second phase that is typically rare earth-rich and lower-melting compared to the principal phase.
  • a preferred method of making magnets based on these compositions is the rapid solidification of an alloy from a melt to produce very fine grained, magnetically-isotropic particles.
  • Melt-spinning or jet-casting is an efficient method of producing rapidly ribbon flakes which may be directly quenched to near optimum single magnetic domain size or overquenched and heated to promote suitable grain growth.
  • the flakes can be comminuted, as desired, to relatively large, air-stable particles which are convenient for further processing.
  • a typical hot-processing practice entails overquenching an alloy of a preferred RE-TM-B composition such as Nd 0.13 (Fe 0.95 B 0.05 ) 0.87 ⁇
  • the thin, friable ribbon is then crushed or ground into particles of a convenient size for an intended hot-pressing operation (50-325 mesh, e.g.).
  • the particles are heated in a non-oxidizing atmosphere to a suitable elevated temperature, preferably about 650°C or higher, and subjected to pressures high enough to achieve a magnetically-isotropic, nearly full-density compact or a magnetically-anisotropic plastically-deformed compact.
  • EP-A-0 133 758 discloses that processing may be accomplished by hot-pressing in a die, extrusion, rolling, die-upsetting, hammering or forging, for example. Hot isostatic pressing is useful to make fully-dense isotropic magnets, but has a slow cycle time.
  • the present invention relates particularly to an improved method of hot-forming and/or hot-working rare earth-transition metal powders or compacts to make relatively large permanent magnets with consistent densities and magnetic properties.
  • a method of hot-forming rare earth-transition metal alloys in accordance with the present invention is characterised by the features specified in the characterising portion of claim 1.
  • hot-working shall mean the application of heat and pressure to a workpiece to cause material flow therein. Such flow induces magnetic anisotropy in substantially amorphous to very finely crystalline RE-TM-B alloys.
  • hot-forming shall mean the application of heat and pressure to a workpiece to cause consolidation thereof and may or may not include hot-working.
  • preferred RE-TM-B compositions of magnetic interest comprise, on an atomic percentage basis, 50-90% of iron or mixtures of cobalt and iron, 10-40% rare-earth metal that necessarily includes neodymium and/or praseodymium and at least about one-half percent boron.
  • iron makes up at least 40 atomic percent of the total composition, and neodymium and/or praseodymium make up at least 6 atomic percent of the total composition.
  • the preferred boron content is in the range of from about 0.5 to about 10 atomic percent for the total composition, but the total boron content may be higher than this without unacceptable loss of permanent magnetic properties. It is preferred that iron makes up at least 60% of the non-rare earth metal content, and it is also preferred that neodymium and/or praseodymium make up at least 60% of the rare-earth content.
  • Permanently magnetic alloys of particular interest are those which contain a predominant RE2TM14B1 phase. This phase tolerates the presence of substantial amounts of elements other than those mentioned above such as aluminium, silicon, phosphorus, gallium, and transition metals other than iron or iron and cobalt, without destruction of permanent magnetic properties.
  • the presence of other elements may be used to tailor magnetic properties. For example, the addition of the heavy rare-earth elements improves magnetic coercivity, and the addition of cobalt has been found to increase Curie temperatures.
  • alloy particles with a substantially amorphous to very finely crystalline microstructure are disposed in a thin-walled container which is flexible at hot-forming temperatures.
  • the particles and container together comprise a workpiece for rapid omni-directional compaction.
  • a container may be made out of a material such as mild steel, stainless steel, copper, tin, aluminium, nickel, glass, or any other material which is plastic at hot-forming temperatures and is not severely degraded by the fluid or semi-fluid present in the die cavity. Similarly, the material of the container should not degrade the RE-TM-B alloy contained therein.
  • the workpiece is then positioned in a die cavity which is larger than the workpiece and is surrounded by a medium which is a substantially incompressible fluid at hot-forming temperatures. This may be accomplished by surrounding the container with a low-melting alloy such as Cu-10Ni or a glass which is molten at hot-forming temperatures, for example.
  • a pre-compact of suitable green strength can be used as the workpiece without a container.
  • the workpiece and compression medium are heated to the desired hot-forming temperature for the RE-TM-B powder.
  • Compaction is preferably accomplished by ramming the medium in a forge or other hot-forming apparatus at a pressure of about 20-80 tons per square inch (276-1,100 MPa). It is preferred that the forming dwell time be limited to reduce the chilling effect of the ram on the compression medium in the die cavity.
  • the preferred temperature range for compaction is above about 700°C but low enough to prevent grain growth beyond about 800 nanometres, and preferably below about 400 nm, during the time needed for rapid compaction in the medium.
  • a suitable RE-TM-B powder is similarly dispersed in a container which is sized to seal with the die walls near the bottom of the die.
  • a compression medium is disposed above the container.
  • An empty cavity portion is provided for the material in the container to flow into when pressure is applied to the medium fluid by a ram.
  • the RE-TM-B powder deforms and moves into the empty cavity. This causes substantial orientation of the grains in the RE-TM-B alloy resulting in magnetic anisotropy.
  • particles 2 of a suitable RE-TM-B alloy with a substantially amorphous to finely crystalline microstructure are placed in a thin-walled, malleable container 4.
  • Container 4 is preferably sealed with respect to the compression medium by welding, brazing or some other suitable method.
  • a compression medium 6 may be cast around the container and allowed to solidify or medium 6 may be contained in another container (not shown).
  • the RE-TM-B container 4 is supported by suitable props such as stilts 7.
  • the combination of the RE-TM-B alloy particles 2, container 4 and the medium 6 (workpiece 18) are then heated to forming-­temperature. This may be done partially or completely outside the forming-die, if desired, to increase cycle time in the press.
  • Die cavity 8 shown in the drawings is heated by electrical resistance coils 10 located in die 12.
  • the medium is located between upper ram 14 and lower ram 16. Both rams are free to reciprocate in die 8.
  • medium 6 and workpiece 18 are heated to the desired forming-temperature.
  • a temperature of about 650°C to 800°C is particularly suited. Extended periods at high temperatures are preferably avoided to prevent excessive grain growth and deterioration of magnetic properties. Deterioration generally begins at grain growth larger than about 400 to 800 nanometres.
  • Compression medium 6 is chosen to be plastic but substantially incompressible at such forming-­temperatures.
  • a suitable material would be lead, a glass-ceramic blend with a softening temperature of about 650°C or any other composition or alloy with an appropriate melting or softening temperature.
  • top ram 14 or bottom ram 16 or both are moved to compress the workpiece 18 in the die cavity. Since medium 6 is substantially incompressible, the force of the movement is transferred isostatically to the powder 2 in container 4.
  • Container 4 shown in Figures 1 and 2 initially has a right-circular cylindrical shape.
  • rapid isostatic pressing causes the top, bottom and sides of the workpiece to indent as shown at detail 20.
  • Alloy particles 2 inside container 4 are consolidated to substantially 100% of the theoretical alloy density.
  • the consolidated alloy has substantially isotropic magnetic properties: i.e., it can be magnetized to equal magnetic strength in any direction.
  • Workpiece 18 can be very large depending on the tonnage of the hot press or forge. Therefore, this invention is particularly useful for making big blocks of material suitable for cutting into smaller magnets of a desired shape.
  • the workpiece could also be shaped to deform non-uniformly when compacted in the medium. Such deformation would result in magnetic anisotropy in the workpiece with the crystallographic c-axes of the RE-TM-B particles being perpendicular to the direction of material flow.
  • Container 30 is sized to form a substantially fluid-tight seal 32 between first chamber 34 and second chamber 36 of die cavity 38.
  • Second chamber 36 is initially empty except for the presence of the container 30.
  • First chamber 34 is filled with an incompressible medium 40 as described above.
  • Die 42 is heated by means of electrical resistance coils 44.
  • a top ram 50 is actuated causing a downward force on the top 52 of workpiece 48 causing it to deform into and fill the second chamber 36.
  • the crystallographic c-axis (the preferred axis of magnetic orientation) of the RE-TM-B particles would be parallel to the direction of applied pressure and normal to the direction of workpiece flow.
  • Each sample was made by filling a mild steel can of the dimensions indicated in the Table with melt-spun, overquenched, roughly crushed, magnetically isotropic Nd .13 (Fe .95 B .05 ) .87 ribbon particles.
  • the particles were densified by tapping to about 45% of the theoretical alloy density of about 7.55 g/cc.
  • the cans were welded shut without evacuation since negligible oxygen contamination would occur from air left in the container.
  • the cans had average wall thicknesses of about 3 mm.
  • Samples 1 to 4 had right-circular cylindrical shapes while samples 5 and 6 were square.
  • the cans were cast in a blend of glass and ceramic that was viscous at temperatures between about 650°C and 800°C. They were heated for the times indicated to elevate the temperature of the can and its contents prior to hot-forming. They were heated outside the die until near the softening temperature and heating was completed in the die cavity.
  • a knuckle press with a double-acting ram was used to very rapidly compact the heated samples at about 750 MPa. The samples were removed from the press and rapidly quenched in an oil-bath. The compression medium was melted away from the samples with a blow-torch. A small segment was cut away from the outside edge and centre of each hot-formed sample.
  • the overquenched starting alloy was magnetically-soft having very little coercivity. All of the rapidly-compacted samples showed good coercivities and energy products. The highest energy product was measured in the sample heated to about 690°C for the shortest time, 40 minutes. It would probably be advantageous to achieve uniform heating in shorter times by using induction, microwave, or some other heating means.
  • An important advantage of the subject method over conventional hot, isostatic compaction in a gaseous medium is the faster cycle time in the compacting press.
  • the sample need be retained in the press only long enough to cycle the rams.
  • the workpieces can be heated outside the press if desired.
  • a fast cycle time in the press is desirable to prevent chilling of the compacting medium by the rams.
  • the cycle time is directly related to the rather slow, controlled pressure build-up time which may be several hours for a large sample.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Powder Metallurgy (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
EP89300871A 1988-03-03 1989-01-30 Schnellverdichtung einer Seltenerd-Übergangsmetallegierung in einer mit Flüssigkeit gefüllten Matrize Withdrawn EP0331286A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16355888A 1988-03-03 1988-03-03
US163558 1988-03-03

Publications (2)

Publication Number Publication Date
EP0331286A2 true EP0331286A2 (de) 1989-09-06
EP0331286A3 EP0331286A3 (de) 1989-11-02

Family

ID=22590556

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89300871A Withdrawn EP0331286A3 (de) 1988-03-03 1989-01-30 Schnellverdichtung einer Seltenerd-Übergangsmetallegierung in einer mit Flüssigkeit gefüllten Matrize

Country Status (2)

Country Link
EP (1) EP0331286A3 (de)
JP (1) JPH01287204A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002100580A1 (en) * 2001-06-13 2002-12-19 Höganäs Ab Method of preparation of high density soft magnetic products

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL68071A (en) * 1982-04-28 1985-12-31 Roc Tec Inc Method of consolidating material with a cast pressure transmitter
CA1236381A (en) * 1983-08-04 1988-05-10 Robert W. Lee Iron-rare earth-boron permanent magnets by hot working
JPS6089533A (ja) * 1983-10-20 1985-05-20 Namiki Precision Jewel Co Ltd Ｃｏ−Ｆｅ系永久磁石合金の製造方法
US4612161A (en) * 1983-10-20 1986-09-16 The United States Of America As Represented By The United States Department Of Energy Fabrication of metallic glass structures
JPS6199605A (ja) * 1984-10-18 1986-05-17 Hitachi Zosen Corp 熱間静水圧圧縮焼成法
JPS61195903A (ja) * 1985-02-25 1986-08-30 Nippon Denso Co Ltd 非晶質成形体の製造方法
DE3518706A1 (de) * 1985-05-24 1986-11-27 Kernforschungszentrum Karlsruhe Gmbh, 7500 Karlsruhe Verfahren zur herstellung von formkoerpern mit verbesserten, isotropen eigenschaften
JPS62176700A (ja) * 1986-01-29 1987-08-03 Mitsubishi Heavy Ind Ltd 静水圧加圧処理装置及び静水圧加圧処理方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002100580A1 (en) * 2001-06-13 2002-12-19 Höganäs Ab Method of preparation of high density soft magnetic products
US6503444B1 (en) 2001-06-13 2003-01-07 Höganäs Ab High density soft magnetic products and method for the preparation thereof
RU2292987C2 (ru) * 2001-06-13 2007-02-10 Хеганес Аб Способ получения магнитно-мягких продуктов высокой плотности
CN1326648C (zh) * 2001-06-13 2007-07-18 赫加奈斯公司 制备高密度软磁产品的方法

Also Published As

Publication number Publication date
EP0331286A3 (de) 1989-11-02
JPH01287204A (ja) 1989-11-17

Similar Documents

Publication Publication Date Title
US8545641B2 (en) Method and system for manufacturing sintered rare-earth magnet having magnetic anisotropy
US5039292A (en) Device for manufacturing magnetically anisotropic magnets
US4808224A (en) Method of consolidating FeNdB magnets
US4925501A (en) Expolosive compaction of rare earth-transition metal alloys in a fluid medium
JP4391980B2 (ja) 磁気異方性希土類焼結磁石の製造方法及び製造装置
EP0231620A2 (de) Dauermagnetherstellung aus einer Seltenerd-Übergangsmetall-Bor-Legierung sehr niedriger Koerzivität
US5009706A (en) Rare-earth antisotropic powders and magnets and their manufacturing processes
EP0599365A1 (de) In der Hitze gepresste Magneten aus anisotropen Pulvern
KR102147715B1 (ko) 희토류 자석의 제조 방법, 및 그에 사용되는 제조 장치
CA1319309C (en) Die-upset manufacture to produce high volume fractions of re-fe-b type magnetically aligned material
EP1011113B1 (de) Herstellungsverfahen eines Seltenerd-Dauermagnets
US4920009A (en) Method for producing laminated bodies comprising an RE-FE-B type magnetic layer and a metal backing layer
US5085716A (en) Hot worked rare earth-iron-carbon magnets
EP0348038B1 (de) Herstellungsverfahren eines Dauermagnetes
US6136099A (en) Rare earth-iron series permanent magnets and method of preparation
EP1770177B1 (de) Verfahren zur Herstellung eines magnetostriktiven Materials
EP0306599B1 (de) Verfahren zur Herstellung von magnetisch anisotropem Magnetmaterial aus Nd-Fe-B
CN100394521C (zh) 磁场中成型方法及稀土类烧结磁铁的制造方法
EP0331286A2 (de) Schnellverdichtung einer Seltenerd-Übergangsmetallegierung in einer mit Flüssigkeit gefüllten Matrize
US4869869A (en) Method of consolidating FeNdB magnets
US4950450A (en) Neodymium iron boron magnets in a hot consolidation process of making the same
GB2206241A (en) Method of making a permanent magnet
EP0443647A1 (de) In der Hitze bearbeitete Magnete aus Seltenerd-Eisen-Kohlenstoff
SU1760563A1 (ru) Способ получени заготовки посто нного магнита
Koper et al. Methods to Improve Other Properties and Characteristics of Magnets and Magnetic Materials

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB

18W Application withdrawn

Withdrawal date: 19890922