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
• • 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 hard magnetic material comprising a rare earth metal, iron and carbon.
• the invention also relates to a magnet on the basis of hard magnetic material.
• a hard magnetic material of the type described in the opening paragraph is known from, inter alia , J. Appl. Phys. 61 3574-3576 (1987).
• the authors of the article classify the compound Nd2Fe14C described therein as not stable. Consequently, this material cannot be used as a starting material for a permanent magnet.
• a hard magnetic material which is further characterized in that the material contains a hard magnetic phase the composition of which corresponds to the formula RE2Fe 14-x Mn x C, wherein RE is at least one element selected from the group formed by Nd (Neodymium), Pr (Praseodymium), Ce (Cerium) and La (Lanthanum), and wherein 0.2 ⁇ x ⁇ 2. It has been found that the value of x cannto be selected randomly. The materials in which x is smaller than 0.2 were found to be insufficiently stable.
• the Curie temperature of the materials in which x is larger than 2 is about room temperature or below room temperature, which is problematic for the magnetic application of these materials.
• the Curie temperature can be raised by substituting a part of the iron present in the material with cobalt.
• the absence of B in the compounds according to the invention is an advantage because as a consequence thereof no toxic, volatile boroncompounds can be formed during the preparations of said compounds.
• the hard magnetic phase of the compounds according to the invention has a tetragonal crystal structure of the ThMn12 type, which is also the case with the known Nd2Fe14B.
• the Curie temperature (T c ) of the compounds according to the invention is between 300 and 550 K.
• the Curie temperature of compounds according to the invention having an identical rare earth metal is lower as the Mn content is higher.
• the hard magnetic materials according to the invention can be obtained in a customary way by melting together suitable starting materials in ratios corresponding to the compositional formula, after which they are subjected to an annealing treatment in a temperature range from 800° C - 950° C in a protective gas or a vacuum for two days; during which treatment recrystallization occurs.
• this stable material can also be prepared by melt spinning a composition with formula Nd2Fe14C, followed by an annealing treatment of the ribbon formed, during which treatment recrystallization occurs.
• Both known methods have the disadvantage that they are less suitable from an economical point of view.
• the hard magnetic properties of the compounds in accordance with the invention are comparable with those of materials on the basis of Nd2Fe14B.
• the magnetization measured at Nd2Fe 13.7 Mn 0.3 C powder at room temperature is approximately 100 Am2/kg.
• This value is comparable with the saturation magnetization which is measured at Nd2Fe14B powder at room temperature. It is noted that this value cannot be regarded as the saturation magnetization, since the material under consideration is magnetically very anisotropic.
• magnets in the form of shaped bodies can be manufactured from said materials in the usual manner.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=19851992

Family Applications (1)

Country Status (5)

Cited By (1)

• 1988
  • 1988-03-24 NL NL8800739A patent/NL8800739A/nl not_active Application Discontinuation
• 1989
  • 1989-03-20 CN CN89101680A patent/CN1036101A/zh active Pending
  • 1989-03-20 EP EP89200693A patent/EP0334445A1/de not_active Withdrawn
  • 1989-03-21 KR KR1019890003486A patent/KR890015303A/ko not_active Withdrawn
  • 1989-03-22 JP JP1067766A patent/JPH028345A/ja active Pending

Non-Patent Citations (3)

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