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
  • B22F3/006—Amorphous articles
  • B22F3/007—Amorphous articles by diffusion starting from non-amorphous articles prepared by powder metallurgy
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/10—Alloys containing non-metals
  • C22C1/1084—Alloys containing non-metals by mechanical alloying (blending, milling)
• • 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

Definitions

• the invention relates to a method for producing a permanent magnet material of a metal-metal-metalloid system, in which the at least one powdery starting component of the metals mixed together with a powdery component of elemental boron or a boron compound or alloy, optionally compacted and finally subjected to an annealing treatment to form the crystalline phase of the permanent magnet material.
• a method for producing a permanent magnet material of a metal-metal-metalloid system in which the at least one powdery starting component of the metals mixed together with a powdery component of elemental boron or a boron compound or alloy, optionally compacted and finally subjected to an annealing treatment to form the crystalline phase of the permanent magnet material.
• Such a method is e.g. in the publication "Journal of Applied Physics", Vol. 57, No. 1, April 15, 1985, pages 4149 to 4151.
• the object of the present invention is therefore to improve the method of the type mentioned in such a way that it can be used in a simple manner to produce a powder of the material system mentioned, which has an extremely fine microstructure similar to that of rapidly quenched material and, if appropriate, also known methods can be compacted into a body made of magnetically oriented material.
• the powder mixture from the starting components is first subjected to a grinding process in the manner of crystalline mechanical alloying, a mixed powder of the at least one metallic starting component being formed with embedded or attached fine particles of the boron component and then that on the other hand, compacted mixed powder is transferred directly into the permanent magnet material with the crystalline phase by means of the annealing treatment.
• powders should also include bodies, particles or particles such as Filings can be understood that only have powder-like shapes.
• the advantages associated with this design of the method are then to be seen in particular in the fact that the mixed powder obtained in this way can be compacted in a known manner without difficulty and can be subjected to an annealing treatment at a relatively low temperature in order to form the desired hard magnetic phase. A previous sintering or melting process with subsequent comminution of the material is therefore not necessary. Nevertheless, extremely fine powders can be obtained with the grinding process.
• M 2 is selected from the group of late transition metals that can be found in the periodic table of the elements.
• M 1 is a rare earth metal or an actinide.
• the corresponding metallic starting components should be in powder form or at least have a powder-like appearance, whereby they can preferably be in elemental form or, if appropriate, also in the form of alloys or compounds.
• Mi and M 2 can in particular be the metals neodymium (Nd) and iron (Fe). Accordingly, the ternary alloy NdFeB is assumed below as an exemplary embodiment.
• powders of the two metallic starting components Fe and Nd and B powder together with hardened steel balls are first placed in a suitable grinding bowl, the ratio of the three types of powder of this powder mixture being determined by the predetermined resulting atom re concentration of the material to be produced from these powders is determined.
• the quantitative ratio of the three elementary types of powder of this powder mixture can be selected such that the composition Ndi 5 Fe 77 B 6 is formed after a diffusion reaction to be carried out.
• the proportion of Nd can be between 10 and 20 atomic% and that of B between 2 and 10 atomic%, with the Fe fraction making up the rest.
• the size of the individual powders can be arbitrary; However, a similar size distribution of the two involved metallic starting components is lm in a range between 5 I and 1 mm, in particular between 20 microns and 0.5 mm advantageously. According to the selected embodiment, Fe powders with a size of the powder particles below 40 ⁇ m and Nd filings with a size of less than 0.5 mm are used.
• the B powder should be as fine as possible, the particles of which are advantageously expanded to less than 10 ⁇ m, preferably less than 1 ⁇ m. In particular, this can be largely amorphous B powder.
• the grinding speed and the ratio of the steel balls to the amount of powder are further parameters that determine the necessary grinding time.
• the mill's steel grinding container is kept under protective gas such as argon or helium and only opened again after the grinding process has ended.
• finely layered powder grains which consist of Fe and Nd layers, form after only about 2 hours of meal.
• the B-particles are embedded or attached to the Fe / Nd interfaces as well as in the elemental metals.
• this layer structure becomes ever finer until it can no longer be resolved by light microscopy after about 10 to 30 hours of eating.
• This then gave rise to powder particles of a mixed powder which consist of an intimate mixture of Fe and Nd with embedded or attached B-particles, the size of which is significantly smaller than 1 ⁇ m.
• the powder particles themselves have a diameter of approximately 1 to 200 ⁇ m. In X-ray examinations of this mixed powder, only strongly broadened intensity maxima of Fe can be seen. There is no evidence of the formation of amorphous FeNd or an FeNd phase.
• the subsequent reaction annealing must also take place under protective gas or under vacuum.
• the annealing can be carried out at one or more different temperatures. A continuous change in temperature is also possible.
• an annealing treatment of, for example, 1 hour at 600 ° C.
• the desired Nd 2 Fe 14 B phase is formed by a diffusion reaction and has excellent hard magnetic properties.
• the reacted powder shows a coercive force of over 10 kOe after embedding in plastic.
• the real advantage of the method according to the invention is that there is an extremely intimate mixing of the elements involved with the grinding process in the manner of mechanical alloying. In the subsequent diffusion reaction, therefore, only very short diffusion paths are required, which can be overcome at relatively low temperatures or short times. This makes it possible to achieve an extremely fine microstructure of the Nd 2 Fe 14 B phase, which corresponds, for example, to that of rapidly quenched material.
• the magnetic hardening of this material is carried out accordingly by Blochwand anchoring.
• a particular advantage is that the annealing can take place at temperatures below 640 ° C, the lowest eutectic temperature in the binary FeNd phase diagram. Above this temperature, a rapid grain enlargement would occur due to the presence of a liquid phase. For the ternary hard magnetic material mentioned, a reaction temperature between approximately 400 ° C. and 640 ° C. appears most suitable.
• annealing at higher temperatures such as 900 ° C for one hour also leads to good values for the coercive force.
• the powder formed is relatively coarse-grained, has foreign phases at the grain boundaries and shows a magnetic hardening mechanism characterized by the blocked domain nucleation. It thus resembles the material which is produced in accordance with the aforementioned EP-A1 and can then be further processed in a known manner to form an anisotropic magnet.
• the temperature treatments known from EP-A1 can also be used advantageously for this.
• this powder can e.g. can be used as a plastic-bonded isotropic magnet.
• composition of the material on which the exemplary embodiment is based can be of the stoichiometric composition when the sample is weighed out tongue Nd 2 Fe 14 B deviate, approximately in the manner as is customary for the processes known from the publications mentioned.
• one or more of the three elements involved can be partially or optionally even completely substituted by other elements.
• Nd can be partially or completely replaced by an element of heavy rare earths, such as Dy or Tb, for example, or completely.
• an element of heavy rare earths such as Dy or Tb, for example, or completely.
• another element of the late transition metals for example Co or Ni, can be provided. Partial replacement with AI is also possible.
• B can be partially substituted by another metalloid.
• the starting powders used depend on the desired compositions.
• the diffusion process it is particularly advantageous for thermodynamic reasons if elemental powders are used, since the driving force for the diffusion reaction is greatest here.
• amorphous B powder is particularly advantageous.
• the elements involved can also be added in the form of pre-alloyed powder, for example as Fe 2 B or as an NdFe phase or an NdFe alloy with 20 to 40 atomic% Fe.
• metastable phases are again preferable to the equilibrium phases for the thermodynamic reasons mentioned.
• At least two metallic starting components M i and M 2 are provided in powder form, each of these two components consisting of a metallic (chemical) element or of an alloy or compound with this element. If necessary, however, it is also possible to start from only a single powdery alloy of the two starting metals Mi and M 2 ; ie, the alloy M 1 - M 2 alone then supplies the two metallic components of the permanent magnet material to be produced. In the case of Nd 2 F 814 B, this would be the alloy Nd 16 Fe 84 in powder form, which together with the B powder forms the powder mixture to be ground.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Power Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Hard Magnetic Materials (AREA)
• Powder Metallurgy (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6297448

Family Applications (1)

Country Status (4)

Families Citing this family (6)

Citations (1)

Family Cites Families (8)

• 1987
  • 1987-03-16 EP EP87103787A patent/EP0243641B1/de not_active Expired - Lifetime
  • 1987-03-16 DE DE8787103787T patent/DE3763888D1/de not_active Expired - Fee Related
  • 1987-03-23 US US07/028,240 patent/US4844751A/en not_active Expired - Lifetime
  • 1987-03-24 JP JP62071322A patent/JPH0645841B2/ja not_active Expired - Lifetime

Patent Citations (1)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events