EP0480722A2 - Procédé de préparation d'un matériau à aimantation permanente du type Nd-Fe - Google Patents

Procédé de préparation d'un matériau à aimantation permanente du type Nd-Fe Download PDF

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Publication number
EP0480722A2
EP0480722A2 EP91309316A EP91309316A EP0480722A2 EP 0480722 A2 EP0480722 A2 EP 0480722A2 EP 91309316 A EP91309316 A EP 91309316A EP 91309316 A EP91309316 A EP 91309316A EP 0480722 A2 EP0480722 A2 EP 0480722A2
Authority
EP
European Patent Office
Prior art keywords
mixture
heating
permanent magnetic
temperature
elements
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.)
Granted
Application number
EP91309316A
Other languages
German (de)
English (en)
Other versions
EP0480722A3 (en
EP0480722B1 (fr
Inventor
Victor Ching-Wah Lee
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0480722A2 publication Critical patent/EP0480722A2/fr
Publication of EP0480722A3 publication Critical patent/EP0480722A3/en
Application granted granted Critical
Publication of EP0480722B1 publication Critical patent/EP0480722B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
    • C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
    • 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
    • B22F3/10—Sintering only
    • B22F3/1017—Multiple heating or additional steps
    • 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 a method of making a material with permanent magnetic properties.
  • the specification discloses a method of combining these elements to make a magnetic material comprising the steps of forming a mixture of iron and one or more rare earth elements; heating said mixture to form a homogeneous molten alloy; and quenching said molten alloy at a rate such that it solidifies substantially instantaneously to form an alloy having an inherent room temperature magnetic coercivity of at least about 5,000 Oersteds as quenched.
  • the specification also discloses the product resulting from the above method.
  • Objects of the present invention are to provide an alternative and improved method of making a permanent magnetic material including the aforementioned less expensive and less scarce elements, and to provide an alternative and improved product.
  • the invention provides a method of making a material with permanent magnetic properties at room temperature comprising the steps of :-
  • the low oxygen environment mentioned at step (g) above is a vacuum or an inert gas environment.
  • the invention also provides a material with permanent magnetic properties made by the above method.
  • the resulting material has improved properties.
  • the material in accordance with the invention has greatly improved magnetic properties and in particular the magnetic coercivity is doubled.
  • the material lends itself to electroplating which prevents corrosion and greatly increases its lifespan.
  • the material can withstand significantly higher temperatures.
  • the method lends itself to automation.
  • One or more than one of the following elements may be added, the amount of these elements is limited to not more than the value specified atomic weight percent as follows:-
  • the above atomic elements are ground and mixed to a powder form by a jet pulveriser, the partccle sizes being between one tenth and ten microns.
  • the mixture is then pressed to form the desired final shape and is then magnetized. Grinding, mixing and pressing are carried out in a nitrogen environment.
  • the formed shape is then heated by application of heat so that the temperature rises in the manner shown in Figure 1 until the sintering temperature is reached after which the temperature is allowed to cool naturally. Finally, the resulting permanent magnet is electroplated.
  • Relatively slow cooling means cooling slowly relative to the disclosure of US 4 496 395.
  • the sintered material is cooled no faster than 75°C/min, especially no faster than 50°C/min, more especially no faster than 35°C/min.
  • a resin may be included in the mixture before heating, and most of the resin is then removed by heating in a vacuum leaving some residual resin, for example 2% by weight, in the finished magnetic material.
  • Figure 2 is a chart of the magnetic properties of materials made from the above constituents by the above method, the differences between the materials arising from the different proportions of the various constituents and Figures 3c to 3f give further details.
  • Figure 4 is a short comparing the properties of the magnetic materials in accordance with the invention (sintered Nd-Fe-B) with the magnetic materials described in the later Croat specification (bonded Nd-Fe-B) and with traditional magnetic materials (SmCo5 and Sm2Co17).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Hard Magnetic Materials (AREA)
EP19910309316 1990-10-10 1991-10-10 Procédé de préparation d'un matériau à aimantation permanente du type Nd-Fe Expired - Lifetime EP0480722B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB909022033A GB9022033D0 (en) 1990-10-10 1990-10-10 A method of making a material with permanent magnetic properties
GB9022033 1990-10-10

Publications (3)

Publication Number Publication Date
EP0480722A2 true EP0480722A2 (fr) 1992-04-15
EP0480722A3 EP0480722A3 (en) 1992-08-05
EP0480722B1 EP0480722B1 (fr) 1994-09-14

Family

ID=10683502

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910309316 Expired - Lifetime EP0480722B1 (fr) 1990-10-10 1991-10-10 Procédé de préparation d'un matériau à aimantation permanente du type Nd-Fe

Country Status (5)

Country Link
EP (1) EP0480722B1 (fr)
DE (1) DE69104004T2 (fr)
ES (1) ES2064050T3 (fr)
GB (1) GB9022033D0 (fr)
HK (1) HK28896A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4331563A1 (de) * 1992-09-18 1994-03-24 Hitachi Metals Ltd Nd-Fe-B-Sintermagnete
DE19541948A1 (de) * 1995-11-10 1997-05-15 Schramberg Magnetfab Magnetmaterial und Dauermagnet des NdFeB-Typs

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4601875A (en) * 1983-05-25 1986-07-22 Sumitomo Special Metals Co., Ltd. Process for producing magnetic materials
JPS636808A (ja) * 1986-06-26 1988-01-12 Shin Etsu Chem Co Ltd 希土類永久磁石
JPS6328844A (ja) * 1986-07-23 1988-02-06 Toshiba Corp 永久磁石材料
ATE106599T1 (de) * 1988-10-17 1994-06-15 Philips Nv Verfahren zum herstellen eines dauermagneten.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4331563A1 (de) * 1992-09-18 1994-03-24 Hitachi Metals Ltd Nd-Fe-B-Sintermagnete
DE19541948A1 (de) * 1995-11-10 1997-05-15 Schramberg Magnetfab Magnetmaterial und Dauermagnet des NdFeB-Typs

Also Published As

Publication number Publication date
DE69104004T2 (de) 1995-03-09
ES2064050T3 (es) 1995-01-16
DE69104004D1 (de) 1994-10-20
EP0480722A3 (en) 1992-08-05
EP0480722B1 (fr) 1994-09-14
GB9022033D0 (en) 1990-11-21
HK28896A (en) 1996-02-23

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