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
  • H01F1/032—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
• • 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 invention relates to a permanent magnet of the FeNdB type, which contains at least one rare earth metal, at least one transition metal and boron and carbon.
• a permanent magnet of this type is known from EP 0 101 552 B1, wherein Nd is preferably used as the rare earth metal and Fe is used as the transition metal.
• Nd is preferably used as the rare earth metal
• Fe is used as the transition metal.
• Such a permanent magnet has good magnetic properties only if the main part of the magnetic structure has a tetragonal crystal structure. This presupposes that the starting materials for the alloy powder contain no impurities or additives or only contain a negligible proportion. Such starting materials are very expensive in terms of the required purity, so that the permanent magnet cannot be produced inexpensively.
• rare earth metals such as Nd
• transition metals such as Fe
• a pure Nd2Fe14C phase ie a pure carbon phase, is produced by melt metallurgy and not powder metallurgy.
• a suitable alloy powder and suitable processes for producing the alloy powder and the permanent magnet are also to be specified.
• the permanent magnet contains two alloy phases, each of which is suitable for the formation of magnetic phases with a tetragonal crystal structure.
• the proportions of B and C are matched to one another in such a way that processing in the presence of oxygen is facilitated.
• the oxygen can be contained in the form of rare earth oxides.
• the carbon added to the known reduction can at least partially be present as an impurity in the transition metal and contributes to the formation of a carbon-rich magnetic phase, so that the non-magnetic phase is reduced proportionately. Since heavy rare earth metals in particular are much cheaper than oxides, the permanent magnets with the two magnetic phases can be produced more cheaply than the known permanent magnets with only a single magnetic phase with a tetragonal crystal structure.
• the essence of the invention is therefore essentially to use two alloy phases suitable for the formation of magnetic phases for the production of a permanent magnet with different magnetic phases, but the same crystal structure, and thereby the advantages of producing a permanent magnet from an oxygen-enriched alloy, the proportion of which when sintering is stabilized to a predetermined value with the help of carbon.
• the knowledge of DE 36 37 521 A1 is combined with the knowledge of EP 0 101 552 B1 and EP 0 320 064 A1 in a sensible manner in order to create a permanent magnet that has high stable values has, can be produced from inexpensive, partially loaded with oxygen or carbon starting materials and the starting materials can be easily processed during production.
• non-magnetic phases of the composition (R) 1Fe4B4 and (R) 1Fe4C4 as well as oxides of the light rare earth metals (LSE2O3) used as metals are also formed, which are also non-magnetic.
• the proportion of rare earth metals (R) in the permanent magnet is preferably chosen so that (R) is the sum of R1 and R2, where R1 is at least one heavy rare earth metal (SSE) and / or an oxide of at least one heavy rare earth metal (SSE2O3).
• the oxide of the heavy rare earth metal becomes metal, while the released oxygen (O2) combines with the light rare earth metal (LSE) to form the non-magnetic LSE2O3 phase, with an O2 content of approximately 0.06 to 1.3 in the permanent magnet % By weight remains.
• the proportion of the transition metal TM is chosen so that it consists of at least 98% iron and / or cobalt.
• magnetic tetragonal phases of the following composition can also form, if as light Rare earth metal neodymium nd is used Nd2 (FeCo) 14B1 or Nd2 (feCo) 14C1.
• the transition metal can also contain additives in an amount of up to 2% of at least one or more of the elements from the group Al, Ti, V, W, Mn, Ni, Si, Cu, Zr, Nb, Ta, Hf, Sn and Pb have.
• the elements Al, Nb, Mo, W, Ta have proven to be advantageous and accumulating in the border phase.
• An alloy powder for producing a sintered permanent magnet with the two tetragonal magnetic phases is characterized in that it consists of an alloy powder with the boron-containing phase and an alloy powder with the carbon-containing phase, at least one rare earth metal with additives and / or oxides and at least one transition metal Impurities exist, the proportion of B being about 0.9 to 1.2% by weight and the proportion of C being about 0.05 to 0.15% by weight.
• a proportion of O2 bi to 1.5 wt .-% may be present.
• the oxides of the heavy rare earth metals and the carbon enable the formation of the two tetragonal phases with cheap starting materials. If necessary, additional carbon and oxygen can be added to obtain the specified proportions.
• the proportion of rare earth metals in the respective alloy phase is characterized in that it contains a first portion (R1) of a light rare earth element LSE with approximately 28 to 34% by weight and a second portion (R2) of at least one oxide of a heavy rare earth element (SSE2O3) about 0.1 to 5 wt .-%, which is used for the preparation of the alloy powder.
• carbon-containing iron (Fe) and / or carbon-containing cobalt (Co) is used as the starting material for the production of the C-containing alloy powder.
• a method which is characterized in that the respective alloy powder the phases containing boron and carbon are prepared in such a way that the starting materials are melted, homogenized after cooling and ground to alloy powder, that additional oxygen (O2) is added to a final concentration of about 1.5% by weight during grinding , and that the alloy powder is aligned in the magnetic field, pressed and, like conventional RE magnets, sintered into a permanent magnet with an energy product of 20 MOe to 40 MOe.
• the master alloy from the light rare earth metals LSE, the oxides, the heavy rare earth metals SSE2O3, the carbon-containing transition metals Fe and / or Co is melted with the additives, the boron or ferroboron and any added carbon, homogenized and ground to alloy powder. Additional oxygen O2 can be added to a final concentration of up to about 1.5% by weight during grinding.
• the carbon content in the alloy powder is brought up to about 0.2% by weight and the powder is then further processed in air.
• the alloy powder is aligned in a constant field of about 14 kOe and at a pressure of about 1 kbar Grünlingen pressed. Green compacts treated in this way have an oxygen content of up to 1.24% by weight.
• the green compacts are heated to about 1,030 ° C. in a vacuum oven and kept at this temperature for about 3 hours.
• Part of the carbon of the alloy combines with the excess oxygen and escapes in the form of CO and / or CO2, which is sucked in and removed with vacuum pumps.
• the subsequent sintering brings the permanent magnet to a final density of around 7.3 to 7.6 g / cm3.
• Part of the carbon escapes and achieves a reduction in the oxygen content and / or the proportion of oxides of the rare earth metals, while the remaining proportion of carbon forms a magnetic phase, which contributes to the excellent properties of this magnet.
• the permanent magnet has excellent mechanical and thermal stability and the oxygenation during the manufacturing process makes the processing of the alloy much easier and easier.
• the main phases of the permanent magnet are tetragonal and magnetic, while only a small proportion of non-magnetic phases are created in the magnetic structure, and no pure, expensive starting materials were used to produce the alloy and the permanent magnet.
• the alloy is homogenized. After homogenization, rapid cooling is carried out, preferably at a cooling rate of approximately 1,000 ° C./min. This is the only way to ensure that the tetragonal magnetic phase with C, e.g. Nd2 (FeCo) 14C1 forms.

Landscapes

• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Hard Magnetic Materials (AREA)
• Powder Metallurgy (AREA)
• Manufacturing Cores, Coils, And Magnets (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6388032

Family Applications (1)

Country Status (4)

Families Citing this family (3)

Family Cites Families (8)

• 1989
  • 1989-08-28 DE DE3928389A patent/DE3928389A1/de active Granted
• 1990
  • 1990-08-27 JP JP2512098A patent/JPH05500134A/ja active Pending
  • 1990-08-27 EP EP90912788A patent/EP0489784B1/de not_active Expired - Lifetime
  • 1990-08-27 WO PCT/DE1990/000653 patent/WO1991003823A1/de not_active Ceased
  • 1990-08-27 DE DE90912788T patent/DE59004054D1/de not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events