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
  • H01F1/12—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 soft-magnetic materials
  • H01F1/14—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 soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
  • H01F1/14708—Fe-Ni based alloys
  • H01F1/14733—Fe-Ni based alloys in the form of particles
  • H01F1/14741—Fe-Ni based alloys in the form of particles pressed, sintered or 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
  • H01F1/0571—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
  • H01F1/058—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IVa elements, e.g. Gd2Fe14C

Definitions

• the invention relates to a method for producing a sintered SEFe permanent magnet with a high proportion of a tetragonal magnetic phase of the SE 2 Fe 14 B and / or SE 2 Fe 14 C type and with high corrosion resistance.
• Such high-energy magnets are pressed and sintered, as shown in EP-PS 0 101 552.
• This excess leads to large proportions of SE-rich non-magnetic phases that accumulate around the magnetic phase.
• These SE-rich non-magnetic phases in conjunction with the magnetic SE 2 Fe 14 B and / or SE 2 Fe 14 C phases lead to a non-corrosion-resistant permanent magnet, since these phases assume different electrochemical potentials, are sensitive to corrosion and influence each other.
• This object is achieved according to the invention in that a proportion of 1.5 to 8 percent by volume of glass powder is added to the alloy on which the permanent magnet is based.
• the glass powder can be ground together with the starting melt for the alloy and can thus be easily introduced into the alloy.
• the sintering and magnetization process takes place in the usual way.
• the non-magnetic phase made of glass includes the corrosion-sensitive, magnetic SE 2 Fe 14 B and / or SE 2 Fe 14 C phases.
• the glass phase is absolutely corrosion-resistant, but worsens the magnetic one
• SEFe permanent magnet Properties of the SEFe permanent magnet are negligible. Since the components of the glass phase have a greater affinity for oxide formation than SE, excess SE can be released in metal form, which easily oxidize on the surface of the permanent magnet can, while it is embedded corrosion-resistant in the glass phase inside the permanent magnet. The tetragonal magnetic crystalline phase is also embedded in glass in a corrosion-resistant manner.
• the permanent magnet of this type also has an increased electrical specific resistance and is particularly suitable for use in motors, magnetic clutches or the like, in which less self-heating due to eddy current formation is important.
• the glass phase can be ensured in the manufacture of the permanent magnet by adding a proportion of 1.5 to 8 percent by volume of glass powder to the alloy.
• the glass powder can be ground together with the raw materials for the alloy. Since glass generally contains a proportion of boron or boron oxide, it can be provided that the glass powder contains a proportion of boron or boron oxide, which is taken into account in the production of the alloy.
• the formation of the glass phase can also be ensured by adding a proportion of 1.0 to 5% by volume of metallic cerium to the starting melt for the alloy, or by a proportion of 1.0 to 5% by volume to the starting melt for the alloy is added to metallic yttrium.
• a sintering temperature of about 900 to 1,100 ° C. is selected to form the permanent magnet. Since the components of the glass phase generally have a lower melting temperature, it is ensured that the sintering is used for the formation de Glass phase required chemical reactions take place.
• the melting temperature of the glass powder can also be influenced by the proportion of boron in the glass and adapted to the manufacturing process.
• Pressing, sintering and any post-heat treatment and magnetization are carried out in a known manner, it being possible for the pressure, the sintering temperature and the treatment tents to be varied.
• Nd and / or Pr with a sufficient oxygen content are preferably used as rare earth metals (SE).
• This oxygen is reduced by yttrium or cerium and forms a glass with other elements.
• Additional glass formers such as Bi 2 O 3 , SiO 2 , B 2 O 3 , CaO, Al 2 O 3 , K 2 O, Na 2 O, Y 2 O 3 , Ce 2 O 3 can also be added to the alloy.
• the alloy can also contain other components, such as Co, Al, Cy, Mo, Ga, C, O 2 .

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

Applications Claiming Priority (2)

Publications (1)

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ID=6401821

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Citations (3)

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• 1990
  • 1990-03-09 DE DE4007533A patent/DE4007533C1/de not_active Expired - Fee Related
• 1991
  • 1991-02-28 WO PCT/DE1991/000176 patent/WO1991014273A1/de not_active Ceased

Patent Citations (3)

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